3.2.1 rated voltage of a motor fed directly or indirectly from a contact system including motors of motor-generator sets highest value of voltage excluding transients which can appear
General
Machine specifications should generally include characteristic curves as outlined in the following subclauses These curves, referred to as the "specified characteristics," must be plotted up to the designed operating limits for each variable.
When the first few machines of a type have been tested, "declared characteristics" shall be produced from the results in accordance with 8.2
Unless otherwise specified, the characteristics of machines that are electromagnetically identical to previously manufactured models for the same user or application will be based on the existing machines In such cases, compliance with these characteristics must be verified through routine testing only.
Efficiency characteristics
Efficiency characteristics must consider losses in external resistances found in the main or excitation circuits Any power utilized for separate excitation should be included in the losses unless specified otherwise, such as being classified as an auxiliary load, in which case this exclusion must be clearly stated.
Commutator type traction motor characteristics
The characteristic curves typically illustrate motor speed, torque, and efficiency as functions of current Alternatively, they may depict vehicle speed and tractive effort at the rail based on current, requiring the specification of gear ratio, wheel diameter, and transmission losses If conventional values are applied, they must align with Figure B.10.
Curves must be created for each excitation condition used in the application; however, if continuously variable field control is utilized, only the maximum and minimum curves are necessary Additionally, the effective machine resistance for each effective field ratio should be specified.
The characteristic curves of traction motors, whether powered directly or indirectly from a contact system or a vehicle-mounted battery, should be plotted at the rated voltage However, if the circuit includes components like transformers or inductors that cause a current-dependent voltage drop at the motor terminals, the curves must reflect a motor voltage that aligns with the nominal supply voltage In such cases, a motor voltage current curve should also be included in the characteristics If this specific information is unavailable, the curves can be drawn using the rated voltage.
The characteristic curves of traction motors in thermo-electric vehicles are typically plotted at the lower voltage of the generator at its continuous rating; however, alternative voltages can be used if agreed upon.
The characteristic curves of a.c commutator motors shall be plotted for the rated frequency and shall show the power factor as a function of current
For motors utilized in rheostatic or regenerative braking, it is essential to present the performance characteristics specific to this mode Unless otherwise specified, the regenerative braking characteristics should be based on a motor voltage that is 1.1 times the nominal system voltage.
The declared braking characteristics may be derived either by calculation from the results of motoring tests or directly from tests in the braking mode.
Main generator characteristics
The characteristic curves illustrate the relationship between voltage and load current For an a.c generator designed to work with a rectifier, these curves will also display the rectifier's output It is important to consider a brushless alternator and its exciter as a unified machine.
Characteristic curves will be created to represent the generator input power available for traction at both maximum and minimum engine speeds If the engine features several predetermined intermediate speed notches, additional curves will be drawn for a sufficient number of these speeds to effectively illustrate the generator's performance.
Each curve will be labeled according to its excitation condition, input power, generator speed, and, if relevant, notch number Furthermore, the efficiency at full power must be displayed for a minimum of two continuous ratings.
NOTE See 5.3 concerning the inclusion of excitation power in the losses when determining the efficiency
Similar characteristics shall be drawn for the generators of main motor-generator sets, due account being taken of the characteristics of the driving motor and regulating equipment.
Auxiliary motor characteristics
The characteristic curves of speed, torque (or output power), efficiency, and power factor for a.c machines should be plotted against motor current at the rated voltage and frequency.
Alternatively, and through agreement between the manufacturer and user, the characteristics may be plotted as a function of speed or output power
Curves shall be drawn for each excitation condition employed in the application.
Auxiliary generator characteristics
The output voltage, power, and efficiency characteristic curves will be plotted against output current at the rated speed, as well as at the minimum and maximum speeds for variable speed machines Additionally, the frequency of the AC outputs will be specified.
In the case of generators operating with a voltage regulator the characteristics shall be plotted at the nominal voltage and the range of excitation current stated
A brushless alternator and its exciter shall be regarded as a single machine.
Auxiliary motor-generator set and rotary converter characteristics
The output voltage, output power, machine speed, and input current will be plotted against output current for the machine operating at minimum, rated, and maximum voltage levels Additionally, the overall efficiency at continuous rating will be provided, and the characteristics of a.c machines will include the power factor.
Machines equipped with a voltage or frequency regulator must have their characteristics defined at nominal voltage or frequency levels Additionally, the range of excitation current should be clearly specified.
When a machine operates an external load, like a blower, the power consumed by that load must be specified Additionally, the overall efficiency statement should be updated to reflect the total input power to the machine at its continuous rating.
Nameplate
All machines addressed in this section of IEC 60349 must have a clearly visible nameplate when located on the workshop floor This nameplate should include essential information such as the manufacturer's name, the machine type designation, the serial number, and the year of manufacture.
The machine serial number and, if applicable, rotation arrow, shall also be easily read when the machine is installed in the vehicle
A serial number, or unique identification number, shall be punched on both the rotor and the stator of each machine.
Terminal and lead markings
Terminal and lead markings shall be in accordance with IEC 60034-8, unless otherwise agreed
7 Test categories and summary of tests
Test categories
General
There are three categories of tests:
Type tests
Type tests are designed to determine the ratings, characteristics, and performance of new machine types If there are changes in the manufacturing location or method, both the user and manufacturer must agree on the type tests to be repeated Additionally, tests to verify the declared characteristics must be conducted on additional machines as specified in section 8.2.
Unless otherwise agreed, the fully tested machine shall be one of the first ten manufactured
A machine can be exempt from type tests if the manufacturer provides a user-acceptable record of previously conducted type tests on a machine with the same electromagnetic design, environmental conditions, and ratings.
Before testing begins, the manufacturer must provide the user with a test specification detailing the tests required to ensure compliance with the standard After the type tests are completed, the manufacturer is obligated to deliver a comprehensive type test report to the user.
By agreement between manufacturer and user, more machines may be fully or partially type tested at intervals
Type tested machines shall also be routine tested.
Routine tests
Routine tests are intended to demonstrate that each machine is sound both electrically and mechanically, and that it is essentially identical with the machine which has been type tested
Routine tests outlined in Clause 9 are typically performed on all machines; however, alternative testing methods can be negotiated between the user and the manufacturer It is also possible to agree that only a random selection of machines from the order will undergo full routine testing, provided that overspeed and dielectric tests, as specified in sections 9.4 and 9.5, are conducted on every machine.
Investigation tests
Investigation tests are optional assessments conducted to gather extra information and should only be performed if there is prior agreement between the user and the manufacturer before placing an order The outcomes of these tests will not affect the acceptance of a machine unless a different agreement has been established.
Summary of tests
Table 1 lists the tests required for compliance with this standard
Table 1 – Summary of tests T est Te m - p e ra tu re ri se
S ou nd- n ess C h ar acter isti cs C o mmu tati o n T ra n s ie n t Star ti n g N o ise Over sp eed D iel ectr ic Vi b rati o n C o tato run- O pt iona l
In te rn a lly ge ne ra te d ch ar ac- ter isti c
Im ba la nc e O pt Ty p e R o ut in e Ty p e R o u ti n e Ty p e R o u ti n e Ty p e Ty p e Ty p e Ty p e R o ut in e R o ut in e Ty p e R o ut in e R o
C lass o f mach in e (s ubc la us e 1 3) T est categ o ry (su b cl a u se 7 1) C lau se o r su b cl au se T rac ti on mo to rs (1 3 1 )
C o mmu ta to r W ound rot or C age rot or
8 6 2* NA NA Annex C NA NA 8 7
NA NA Annex C NA NA
9 6 9 6 Ma in mo to r- generat or se ts ( 1 3 3 ) Mo to r Generat or 8 1 8 1 9 1 9 1 8 2 2 8 2 3 9 2 2 9 2 3 8 3 2* 8 3 3* 9 3 2* 9 3 3* 8 4 2* 8 5 8 6 3 NA Annex C NA NA 9 4 5 9 4 5 9 5 9 5 8 8 8 8 9 6 9 6 9 9 Aux ilia ry mo to rs (1 3 4 )
C o mmu ta to r W ound rot or C age rot or
9 6 9 6 9 6 Aux ilia ry generat ors (1 3 5 )
NA NA Annex C NA NA
9 6 9 6 Aux ilia ry mo to r- generat or se ts R o ta ry co n v e rte rs (1 3 6 )
Not applicable (N/A) to all machines in the class; please refer to the relevant clause All machines, including those tested, must undergo routine testing.
Temperature-rise tests
General
Tests will be conducted at guaranteed ratings, but the user and manufacturer may agree to alternative testing methods for main alternators These methods include: a) testing at rated frequency with terminals short-circuited, adjusting excitation to achieve an output current that simulates the stator winding temperature rise of a load test at continuous rating and lower voltage; b) testing at rated frequency on open circuit, with excitation set to the specified value for continuous rating at higher voltage.
When the output of an alternator is rectified, it shall be type tested with its rectifier or with one having similar characteristics
If one or more of the following conditions apply, the tests shall be carried out with voltage and current waveforms closely resembling those in service:
1) if the ripple factor of the load current in service exceeds 10 % of the guaranteed rating;
2) if the excitation is pulse controlled
If meeting this requirement is not feasible, the user and manufacturer must agree on a method that considers the impact of the differences between the test and service supplies.
NOTE 1 In the case of machines operating on rectified single-phase alternating current at power frequency (50 Hz or 60 Hz) the tests may be carried out using the supply frequency of the place of manufacture whether or not this differs from that of the place of use, provided that the current ripple factor is not less than that in service The error in the results will be negligible and correction will not be necessary
NOTE 2 In the case of continuous rating tests, the time to attain steady temperatures may be shortened by commencing the tests at an increased load or reduced ventilation provided that the rated conditions are subsequently maintained for at least 2 h or until it is demonstrated by appropriate means that steady temperatures have been reached
NOTE 3 Steady temperature is defined as a change in temperature rise of less than 2 K during the final hour of test
NOTE 4 If the declared excitation current differs from the specified value, the tests have to be carried out with the declared value.
Ventilation during temperature-rise tests
Machines must be tested under service conditions, ensuring that all components affecting temperature rise, such as ducting and filters, are in place This includes configurations that provide equivalent conditions for accurate assessment.
In systems utilizing forced ventilation for cooling, it is essential to measure both the static pressure and air flow at the machine's air inlet to establish a table that illustrates the relationship between these two parameters.
Typically, no additional cooling from vehicle motion is provided; however, in specific situations, such as with fully enclosed traction motors where cooling is crucial, it may be utilized if there is mutual agreement between the manufacturer and the user.
Judgement of results
The temperature rises of the windings, commutators or slip rings at the "commencement of cooling" shall not exceed the values given in Table 2.
Limits of temperature rise
The different thermal classes of insulating materials are defined in IEC 60085
Table 2 outlines the allowable temperature rise limits, measured on the test-bed above the cooling air temperature, for windings and other components insulated with materials from the current thermal classes used in machine construction relevant to this standard.
If different parts of the same machine have different classes of insulation, the temperature- rise limit of each part shall be that of its individual class
Table 2 – Limits of temperature rise for continuous or other ratings
Thermal class of Insulation system, Part of machine Method of measurement 130(B) 155(F) 180(H) 200
Stationary winding or rotating field windings of alternators or synchronous motors Resistance 130 K 155 K 180 K 200 K
All other rotating windings Resistance 120 K 140 K 160 K 180 K
Damping windings Electrical thermometer The temperature rise shall not be sufficient to endanger any windings or other parts
For totally enclosed machines, limits of Table 2 are increased by 10 K
In situations where machines are exposed to heat from an engine or other sources, users and manufacturers may agree to adopt temperature rises that are lower than those specified in Table 2.
NOTE Commutator temperature is only one of many factors affecting commutation and, whilst in general commutation improves with reduction in temperature, this is not invariably the case.
Short-time overload temperature-rise test
If short-time overload ratings are specified, they shall be verified by one or more tests carried out as follows
To determine the starting temperature rise from the previous rating test, continue plotting the cooling curve for the critical winding until the temperature rise reaches the "start" value indicated in Table 3 This prediction should be made by extrapolating the curve for no more than 5 minutes beyond the last reading At this predicted time, apply the specified overload under normal ventilation conditions and maintain it for the designated duration The test will conclude at this point, and the temperature rise will be measured using resistance measurement as outlined in Clause A.5.
If the observed temperature increase is within 20 K of the final value specified in Table 3, adjustments to the rated current or duration can be calculated to achieve the temperature rise indicated in Table 3.
If the measured temperature rise differs from the Table 3 value by more than 20 K, the test shall be repeated with amended values of either current or duration
Table 3 – Temperature rise for short-time overload rating
Thermal class of Insulation Part of machine
Stationary windings or rotating field windings of alternators or synchronous motors
NOTE 1 The critical winding of commutator type machines is normally the armature For polyphase machines it is normally the stator
NOTE 2 If agreed between user and manufacturer, the temperature of other parts (e.g the rotor cage, commutator, bearings, etc.) may be measured
NOTE 3 For totally enclosed machines the temperature rises given in Table 3 should be increased by 10 K
NOTE 4 An alternative method of obtaining the starting temperature rise may be employed if agreed between manufacturer and user.
Characteristic tests and tolerances
General
Tests to demonstrate compliance with the specified characteristics may be by any suitable method (examples being given in Annex B), load tests being carried out with the machine hot
Direct measurement of input and output should only be conducted with high-accuracy measuring equipment Efficiency values obtained from tests must be adjusted to the reference temperature, along with other results if the correction is deemed significant.
Characteristic tests on pulsating current machines can be performed using direct current (d.c.), but it is essential to consider additional resistance losses caused by the pulsating current, as outlined in Annex B, when calculating efficiency.
Efficiency or loss tests are required only on those machines which are to be fully type tested as defined in 7.1.2
Reversible machines shall be tested in both directions of rotation.
Commutator type traction motors
8.2.2.1 Sufficient test readings (for example four or five for each curve) shall be taken to enable declared characteristic curves corresponding to the specified characteristics to be plotted
Declared speed/current curves are generated by averaging the speeds of the first four tested machines These averages must adhere to the specified values within the design tolerances outlined in Table 4 Additionally, the speed of any individual machine should not deviate from the declared speed beyond the manufacturing tolerances specified in the same table.
The declared torque/current curves shall be calculated from the speed/current curves using efficiency values derived from the type test
NOTE 1 As stated in 5.4, declared braking characteristics may either be calculated from the declared motoring characteristics or be derived from tests in the braking mode Braking characteristics are not toleranced, compliance of the machine with the specified basic electro-magnetic characteristics having been demonstrated in the motoring mode
Table 4 – Tolerances on the speed of commutator type traction motors
Excitation condition or effective field ratio
Point Ch1 Point Ch2 Point Ch1 Point Ch2
Point Ch1 represents the current displayed on the specified curve at 80% of the maximum working speed If the speed at that point is lower, it indicates the minimum current shown.
80 % of the maximum working speed (see Figure 1)
Point Ch2 is at 90 % of the maximum current shown on the relevant curve (see Figure 1)
Between these points the tolerances shall be linearly graded with respect to current
Where the characteristics of a separately excited machine differ from Figure 1 such that
Table 4 cannot be applied (for example a rising characteristic) the tolerance shall be agreed between manufacturer and user
NOTE 2 Such a machine could be treated similarly to a main generator (see 8.2.3) in that the speed/current characteristic may be modified following the type test with the tolerance on speed for the routine test at the modified values Any adjustment to the specified excitation should be within the capability of the control system and of the field winding guaranteed rating(s)
The tolerances shall be increased by 1 % in the case of motors with a guaranteed rated output below 75 kW
The excitation currents of a separately excited motor and the effective field ratios of a series excited motor can vary from the specified values, as long as they stay within the limits of the excitation control equipment's capacity.
8.2.2.3 The losses at the guaranteed rating shall not exceed the value derived from the specified characteristic by more than 15 %
NOTE When a conventional rather than a measured value is used for the transmission losses, the comparison between specified and declared losses should be based on the machine losses only.
Main generators (refer to Figure 2)
8.2.3.1 Alternators designed to operate with rectified output shall normally be tested with a suitable rectifier A brushless alternator and its exciter shall be regarded as a single machine
When full power testing of main alternators is impractical, appropriate open-circuit and short-circuit tests must be conducted to verify characteristics and assess efficiency using the summation of losses method, as outlined in Annex B The specifics of these tests should be mutually agreed upon by the user and the manufacturer.
8.2.3.2 In the case of a regulated generator, sufficient readings shall be taken to enable declared characteristic curves corresponding to the specified characteristics to be plotted directly from the readings or by calculation from the results of open-circuit and short-circuit tests The curves shall be based on the average of tests on the first four machines
At this stage, the manufacturer is allowed to adjust the excitation values, which will be used for all future tests Additionally, it must be shown that the excitation needed to achieve the specified characteristics is compatible with the capacity of the regulating equipment.
The maximum current and voltage on the regulated section of the full power characteristic (points Ch1 and Ch2) must not deviate from the specified curve values by more than ±5%.
8.2.3.3 In the case of an inherent characteristic generator, sufficient readings shall be taken on the first four machines tested to enable the declared characteristics to be plotted as the average of the four results The excitation values may be modified from those of the specified curves, but the revised values shall then be retained for all subsequent tests
The declared maximum current, the voltage at the rated current and the open-circuit voltage
(points Ch1, Ch2 and Ch3) shall not vary from the corresponding values on the specified curve by more than ±5 %
8.2.3.4 For both regulated and inherent characteristic generators the losses at the two continuous ratings (defined in 3.1.2) shall not exceed the specified value by more than 15 %.
Auxiliary motors
To derive the characteristic curves for the specified features, adequate readings must be collected from the first four tested machines, allowing for the average of these readings to be calculated.
In addition, declared speed and torque (or output) curves shall be determined at the maximum and minimum machine voltages if these differ by more than ±5 % from the rated value
The declared characteristic curves for current values between 0,8 and 1,2 times the guaranteed rating shall not differ from the specified characteristics by more than ±5 %
The losses at the guaranteed rating shall not exceed the specified value by more than 15 %.
Auxiliary generators
To derive the characteristic curves for the first four tested machines, sufficient readings must be collected to reflect the specified characteristics accurately For machines equipped with a voltage regulator, it is essential to conduct at least one test with the regulator in operation.
The declared output voltage of an unregulated generator shall not differ by more than ±5 % from the specified characteristic at any point between open circuit and the guaranteed rating
The voltage tolerance of a regulated generator depends on the characteristics of the regulator rather than the machine itself While excitation currents can vary from the specified values, they must stay within the regulator's capacity.
The losses at the guaranteed rating shall not exceed the specified value by more than 15 %
The open-circuit and short-circuit characteristics of alternators must be measured at the rated speed, with the average characteristics being compiled to establish a foundation for routine test evaluations.
Auxiliary motor-generator sets and rotary converters
To derive the characteristic curves for the first four tested machines, sufficient readings must be taken to ensure accuracy based on the average of these readings For regulated machines, it is essential to conduct at least one test with the regulators in operation.
For unregulated machines, the output voltage must not deviate from the specified characteristic by more than ±5% across all points from open circuit to rated current Additionally, unless stated otherwise, the speed-current characteristic does not have a tolerance.
The tolerances on the voltage and frequency of a regulated machine are functions of the characteristics of the regulators and not those of the machine
A regulated machine's operating current must remain within the declared range of its characteristic curve, although it may vary from the specified range as long as the revised values are still within the regulator's capacity.
The machine's losses at the guaranteed rating must not exceed the specified value by more than 15% However, for machines that drive an external load, the input at the guaranteed rating should not exceed the specified value by more than 5%.
Commutation tests
General
Commutation test results must be documented in compliance with IEC 60638 standards The machines should endure the tests without experiencing mechanical deterioration, flashover, or any permanent damage that could impair their satisfactory operation post-test.
Tests should be conducted with the machine at elevated temperatures, with each test point lasting no longer than 30 seconds If excessive heating occurs during high current tests, the machine can be operated at a lower current to allow it to cool to a more typical operating temperature.
Machines which operate with separate or compound excitation shall be tested with the appropriate excitation conditions for each point
Machines must undergo testing in all directions of rotation relevant to their specific application It is essential that the brushes remain undisturbed between tests conducted in different rotational directions.
Tests can be conducted in any preferred order of currents and rotations When the rotation direction is reversed, the machine should operate in the new direction for a maximum of 15 minutes, using a current and speed that ensure optimal contact between the brushes and the commutator.
Machines tested in one direction only shall have run for a sufficient time to ensure that the brushes are fully bedded in before each test point
Alternating and pulsating current motors are typically tested at their rated frequency for a.c motors and at the service pulsation frequency along with the current ripple factor for pulsating current motors In specific instances, adjustments to the frequency may be made as outlined in Note 1 to 8.1.1.
Traction motors (refer to Figure 1)
Commutation tests shall be made at the following points
– Commutation point number 1 (Com1): at the maximum speed shown on the characteristic with the motor taking the highest current which can normally be drawn at this speed in service
– Commutation point number 2 (Com2): at the guaranteed rating current
– Commutation point number 3 (Com3): at the maximum current shown on the relevant curve
Tests Com2 and Com3 shall be carried out at the maximum and minimum excitation used at these points in service
The test voltage shall be chosen as follows:
– for motors supplied either directly or indirectly from a contact system:
• the voltage corresponding to the highest voltage of the system;
– for motors for thermo-electric vehicles:
• the voltage at the motor terminals when operating on the full power characteristic of the main generator;
– for motors supplied from a battery:
• the voltage corresponding to the no-load voltage of a fully charged battery
When conducting tests Com2 and Com3 at the specified voltage, if the motor speed exceeds that of Com1, the voltage must be decreased to achieve the speed of Com1.
In cases where the maximum voltage applied to the motor is restricted by control mechanisms, testing must be conducted at this limited voltage.
For series excited motors that are permanently connected in series without mechanical coupling or automatic anti-slip protection, a commutation test must be conducted This test should be performed at maximum field conditions, with the load current set to ensure the motor operates at its maximum working speed when supplied with 1.5 times its rated voltage for line or battery-operated motors.
1,5 times its maximum voltage for a thermo-electric vehicle motor
NOTE Equipment which only indicates the presence of wheelslip and leaves corrective action to the driver is not sufficient to give exemption from the test
Motors designed for regenerative or rheostatic braking must undergo testing at several key values of speed and current, typically four or five, to ensure they operate effectively within the defined braking characteristic curves.
In cases where the regenerative or rheostatic braking circuit exhibits a unidirectional current ripple exceeding 10%, it is essential to conduct commutation tests in the braking mode under conditions that closely mimic actual service scenarios.
Main generators (refer to Figure 2)
Commutation tests shall be made at the following points on the full power characteristic as shown in Figure 2
– Com2: the current at the continuous rating at lower voltage;
– Com3: the current at the unloading point or, for an unregulated generator, 50 % of the current for test Com2.
Auxiliary motors and generators and motor-generator sets
Commutation tests must be conducted at no more than four strategically selected points to encompass the entire range of the machine's characteristics at both maximum and minimum voltages, as specified in section 3.5.
Transient tests
General
Transient tests are essential for d.c and pulsating current motors connected to a contact system, whether directly or indirectly However, these tests are unnecessary if the machine's power supply incorporates electronic equipment that restricts the current during reconnection after an interruption or voltage spike, ensuring it does not exceed the maximum specified in the characteristic.
The machine shall withstand each test without mechanical deterioration, flashover or permanent damage, permanent damage being that which would prevent successful operation of the machine after the test
For high-power motors, the constraints of the testing facility may hinder complete adherence to the designated testing protocol In these situations, it is essential for the manufacturer and the user to reach a consensus on an alternative testing procedure.
Traction motors and motors of main motor-generator sets
The test will utilize a manual or automatic switch to cut off the supply from the contact system while the motor is drawing its guaranteed rated current, followed by reconnection approximately 1 second after the interruption.
In circuits equipped with an automatic device for inserting resistance or protecting against excessive current during reconnection, testing must be conducted with this device in the circuit or after a time interval that matches the device's operating time.
The speed of rotation of the motor shall be maintained as constant as possible during the period of interruption
Field weakening should be tested using a single method—such as field diversion, tap changing, or current regulation in separate excitation—by conducting three tests at maximum field and three at minimum field These tests should be spaced a few minutes apart and utilize field weakening devices that are identical or equivalent to those used in actual service.
Field weakening can be achieved through various methods on different notches In such cases, testing must be conducted three times at both maximum and minimum excitation levels for each field weakening method used.
A suitable transient recorder must confirm that, at the moment of reconnection, the motor terminal voltage (or the voltage across the motor and inductor if one is permanently connected in series) is at least equal to the highest system voltage Additionally, it is essential that the voltage does not drop below 0.9 times the nominal system voltage thereafter.
Auxiliary motors, auxiliary motor-generator sets and auxiliary rotary
The tests will be conducted with the motor fitted with control and protective equipment to replicate standard operating conditions For motor-generator sets, the circuit must incorporate both voltage and frequency regulators.
The supply will be interrupted and restored four times consecutively, ensuring normal load conditions are re-established between each interruption The motor will operate at its guaranteed rating using the weakest field achievable during service Two tests will be conducted with an interval of about 1 second between interruptions and restorations, while the other two tests will have an interval slightly shorter than the operating time of the protective equipment.
The supply voltage conditions shall be as defined in 8.4.2
For machines capable of feeding back into a vehicle's main circuits during supply interruptions, this scenario should be simulated by short-circuiting the machine or using other appropriate methods However, this simulation is unnecessary if the normal circuit incorporates components, like a diode, that effectively prevent feedback.
Voltage jump test on auxiliary motors, auxiliary motor-generator sets
The machine will be supplied with its minimum voltage via a series resistance, which, when short-circuited, allows the voltage to reach its maximum value Additionally, the circuit will include the machine's standard control and protective equipment, such as the generator voltage regulator.
The test will be conducted five consecutive times, ensuring that minimum voltage conditions are reinstated between each voltage increase A transient recorder will verify that the supply voltage, after short-circuiting the resistance, remains above the nominal system voltage.
Auxiliary motors driving mechanical loads shall be tested at the load normally imposed on the motor when operating at minimum voltage and field
Motor-generator sets must undergo testing to ensure the generator delivers its guaranteed rated power or the maximum power it can supply at the minimum input voltage, provided this is lower than the guaranteed rating.
Short-circuit tests on main and auxiliary alternators
Main and auxiliary alternators must undergo testing that simulates fault conditions, utilizing a test circuit that incorporates the protection and excitation systems used in service or their equivalents.
Each test shall consist of a short circuit applied for 5 s with the machine operating at its rated speed on open circuit with the guaranteed rated value of excitation current
At the conclusion of each test, it shall be shown that the protection has operated and that the machine has suffered no electrical or mechanical damage
The short circuit shall be applied as follows:
– alternators supplying a mainly rectified output: one test shall be made with the full rectifier bridge short-circuited and another with one bridge arm short-circuited;
Alternators that primarily supply alternating current (A.C.) loads require two specific tests: one involving a short circuit across all phases simultaneously, and another focusing on a single line-to-line short circuit In systems with a solidly earthed neutral, a single line-to-neutral short circuit is also tested.
Starting tests
General
Starting tests are required for specific types of machines, including single-phase a.c commutator motors designed for locomotives and similar vehicles, main motor-generator sets, and various auxiliary motors, motor-generator sets, and rotary converters.
Single-phase a.c locomotive motors
When placing an order, it is essential to run the motor at its maximum current for one minute while hot, unless otherwise specified The power supply must maintain the rated frequency, with the voltage adjusted to ensure the motor operates at approximately 5% of its maximum working speed Additionally, the ventilation should match the conditions experienced during normal service.
The test will be conducted in both rotational directions and must not result in any permanent damage to the commutator, where permanent damage is defined as any impairment that could hinder the machine's future satisfactory performance.
Main motor-generator sets
The tests shall be carried out with the normal starting and protective gear and, in the case of a.c motors, at the rated frequency
Machines intended to operate on pulsating current or with pulse control shall be tested with supply conditions closely resembling those in service
The motor will undergo two consecutive starts at minimum voltage, followed by two starts at maximum voltage, with a 5-minute interval between each attempt It will be loaded to ensure that the torque produced is comparable to that experienced during normal service conditions.
The initial performance of the machine must be satisfactory, ensuring that no part experiences excessive temperature rise, flashover, or permanent damage to the commutator During testing at maximum voltage, the machine's voltage should not drop below 0.9 times the specified maximum value If limitations of the testing facility hinder this requirement, the manufacturer and user may mutually agree on an alternative testing procedure.
Auxiliary motors, auxiliary motor-generator sets and auxiliary rotary
The tests shall be carried out with the normal starting and protective gear and, in the case of a.c motors, at the rated frequency
Machines intended to operate on pulsating current or with pulse control shall be tested with supply conditions closely resembling those in service
The motor will undergo five consecutive starts at minimum voltage, followed by five starts at maximum voltage, with a two-minute interval between each start It will be loaded to ensure that the torque produced closely resembles that experienced during normal service conditions.
The performance and supply capacities shall be as specified in 8.6.3.
Overspeed tests
Unless agreed otherwise, overspeed tests are type tests only on machines other than commutator and wound rotor machines Details of the tests are given in 9.4.
Vibration tests
Internally generated vibration characteristics
A quantitative vibration measurement is to be taken as a type test
For vibration measurement during type test the machine can simply be placed on the test board without any mounting equipment The velocity of vibration at machine speeds up to
3 600 rev/min shall be within the limit of 3,5 mm/s For speed above 3 600 rev/min the velocity shall be less than 5,25 mm/s
If the machine design has no fixed bearing the longitudinal velocity of vibration could be excluded
For additional information see IEC 60034-14
Measurements on variable speed machines shall be taken at a number of speeds covering the whole working range
Excessive vibration velocities may occur due to resonances in the test mountings; however, these should be ignored if they do not align with a specific working speed and if the overall velocity levels remain within acceptable limits across the speed range.
Should such a resonance occur at a discrete working speed the test shall be repeated with an alternative mounting arrangement
NOTE The effect of externally generated vibrations on the machine is outside the scope of this standard
Reference should be made to IEC 61373
Short-time soundness test
General
A short-time soundness test shall be carried out on all machines except those with cage-type rotors.
Test conditions
The machine will operate under load for approximately 1 hour from a cold start, with test conditions such as voltage, current, excitation, and ventilation selected to achieve final winding temperature rises that closely align with those observed at the conclusion of the guaranteed rating type test.
Motors which operate in service on pulsating current shall be tested on direct current
AC generators may be tested on short circuit If the output of an a.c generator is to be rectified, the test may be carried out without the rectifier
Machines may be tested in pairs, one acting as a motor and the other as a generator
The method of measuring temperature and resistance shall be in accordance with Annex A, except that the plotting of heating and cooling curves shall be as detailed in 9.1.3.
Plotting of heating and cooling curves
Heating or cooling curves must be plotted for the first ten machines of an order, following the type test procedure The curves from each winding of the first four machines will be averaged to establish a temporary acceptance or rejection criterion for subsequent machines until all ten have been tested The final "declared heating or cooling curve" for each winding will be determined as the average of the ten tests conducted.
If machines are tested in pairs, separate averages shall be established for generators and motors
For subsequent tests, a single resistance value or temperature measurement taken within 1 minute of cooling initiation is adequate It is essential to record the time of this reading to facilitate comparison with the corresponding declared curve, and the measurement period may be extended beyond 1 minute as specified in Clause A.4.
Judgement of results
A machine passes the routine soundness test if the temperature increase, measured from the start of cooling, does not deviate from the specified curve values in section 9.1.3 by more than ±8% or ±10 K, whichever is greater.
If the declared curve temperature increases approach the limits specified in Table 2, it is acceptable for individual routine test results to exceed these limits.
If a machine surpasses the specified temperature rise limit, it can undergo a type test at its guaranteed rating and will be accepted upon passing this evaluation.
Variations in material quality within acceptable limits can lead to significant changes in average temperature increases within an order If these variations cause repeated failures in routine tests, even after passing type tests, a new declared curve may be set, which cannot exceed 5% above the previous curve.
Characteristic tests and tolerances
General
Tests can be conducted using any appropriate method while the machine is hot Readings do not require correction to the reference temperature unless failing to do so would lead to the rejection of the machine.
Efficiency tests are not required, nor are tests in the braking mode
Machines which operate, in service, on pulsating current shall be tested on direct current and machines intended for a synthesized polyphase supply shall be tested on sinusoidal alternating current
Reversible machines shall be tested in both directions of rotation.
Commutator type traction motors (see Figure 1)
Speed measurements should be conducted at points Ch1 and Ch2 under both maximum and minimum excitation conditions For separately excited motors, it is adequate to take a reading at point Ch2 only, while curves should be plotted for constant excitation.
The speeds shall not vary from the declared values by more than the manufacturing tolerances given in Table 4.
Main generators (refer to Figure 2)
For a regulated generator, measurements must be recorded at specific points along the full power regulated curve, using the separate excitation currents set by the type test.
– Ch1: at the maximum current on the regulated portion of the declared characteristic;
– Ch2: at the maximum voltage on the regulated portion of the declared characteristic
The maximum current and maximum voltage shall not vary from the corresponding values on the declared curve by more than ±5 %
If the maximum current indicated on the declared characteristic falls within the regulated portion, the current tolerance is not applicable It is sufficient to show that the excitation current remains within the declared limits at the maximum load current.
In the case of an inherent characteristic generator, readings shall be taken at the following three points on the highest power curve:
– Ch1: the voltage corresponding to maximum current;
– Ch2: the rated current at lower voltage;
The maximum current at point Ch1 and the voltages at points Ch2 and Ch3 shall not vary from the declared values by more than ±5 %.
Alternative tests for alternators
These shall consist of open-circuit and short-circuit tests
The open-circuit voltage and short-circuit current shall not vary from the values established during type testing by more than ±5 %.
Auxiliary motors
The speed of commutator type machines shall be measured at the guaranteed rating with maximum field and shall not differ from the declared value by more than ±5 %
The slip of asynchronous machines shall be measured at the guaranteed rating and shall not vary from the declared value by more than ±20 %.
Auxiliary generators
For unregulated DC generators, the open circuit voltage and the voltage at rated current must be measured while the machine operates at its rated speed These voltages should not deviate from the specified values by more than ±5%.
For regulated d.c generators, the excitation currents required to generate the rated voltage at open circuit at maximum speed and at maximum load and minimum speed shall be measured
They shall not vary from the declared values by more than ±5 %
For a.c generators, the open-circuit voltage and short-circuit current at rated speed shall be measured at two specified values of excitation which, unless otherwise agreed, shall be
100 % and 50 % of the maximum excitation current The voltages and currents shall not vary from the values established during type tests by more than ±5%
Machines using a regulator can have their tolerance expanded as long as the specified output voltage characteristic is achievable within the regulator's capacity and the temperature rise of the field winding complies with soundness test standards.
Auxiliary motor-generator sets and converters
For unregulated sets, it is essential to measure the output voltage and machine speed at both maximum and minimum voltage levels with the generator in open circuit, as well as when delivering its rated output current In the case of an a.c generator, the output must adhere to the specified power factor Additionally, the output voltage and frequency, if applicable, should not deviate from the declared curve values by more than ±5%.
For regulated sets, a maximum of four readings should be taken at selected points to ensure that any declared characteristic can be achieved within the regulating equipment's capacity Typically, measurements at maximum supply voltage with no load and at minimum supply voltage with maximum load are adequate; however, additional measurements may be necessary in certain situations The tolerances for voltage and frequency are determined by the regulators rather than the machine itself Furthermore, the input current at the load test points must not deviate from the declared value by more than ±5%.
Commutation routine tests
General
The general requirements for commutation routine tests are the same as those given in 8.3 for type tests except that pulsating current motors may be tested on direct current.
Traction motors (refer to Figure 1)
Traction motors shall be tested at points Com1, Com2 and Com3 at the minimum excitation used at these points in service
An additional test for motors connected permanently in series is not required nor are braking tests.
Main generators (refer to Figure 2)
Main generators shall be tested at points Com1 and Com2.
Auxiliary motors and generators and motor-generator sets
Motors must undergo testing at their maximum voltage, with a current set at 1.5 times the guaranteed rating or at the maximum current for the specific application, whichever is lower The testing speed should reflect the maximum achievable speed under normal service conditions.
Generators (including those forming part of a motor-generator set) shall be similarly tested but at the nominal output voltage for the test conditions
Motors of motor-generator sets shall be tested at their minimum voltage with the generator supplying the maximum output attainable in normal service for the test conditions.
Overspeed tests
General
Overspeed tests are standard procedures for commutator and wound-rotor machines, and they are considered type tests for other machine types unless otherwise agreed During these tests, machines must operate for 2 minutes at the speeds outlined in sections 9.4.2 to 9.4.5 while hot, ensuring that they exhibit no permanent deformation and successfully pass the dielectric tests specified in section 9.5.
Traction motors
Traction motors shall be tested at 1,2 times the maximum working speed as defined in 3.7.1
When multiple series-excited motors are permanently connected in series without mechanical coupling, the overspeed limit should be raised to 1.3 However, if wheelslip protection is implemented, this factor can remain at 1.2, provided there is mutual agreement between the user and the manufacturer.
NOTE Equipment which only indicates the presence of wheelslip and leaves corrective action to the driver is not sufficient to give exemption from the increased overspeed factor.
Main or auxiliary engine-driven generators
Main or auxiliary engine-driven generators shall be tested at 1,2 times the maximum working speed as defined in 3.6.2.
Generators driven by a vehicle axle
Generators driven by an axle shall be tested at 1,2 times the maximum working speed defined in 3.6.3.
Main or auxiliary motor-generator sets, auxiliary converters and
Main or auxiliary motor-generator sets, auxiliary converters and auxiliary motors shall be tested at 1,2 times the maximum working speed defined in 3.6.4.
Dielectric tests
The test voltage is typically applied using an alternating current (a.c.) with a near sinusoidal waveform, within a frequency range of 25 Hz to 100 Hz However, direct current (d.c.) testing can be utilized if there is prior agreement between the user and the manufacturer before the order is placed.
The test voltage must be applied between the windings of each circuit and the frame, with all other circuit windings connected to the frame This testing procedure is applicable solely to new machines, ensuring that all components are in place as they would be during normal operation.
The test shall be carried out immediately after the routine tests specified in the preceding clauses
The test voltage should be applied gradually, starting at no more than one-third of the final value specified in Table 5 Once the final value is achieved, it must be sustained for a duration of 60 seconds.
1 a) Windings directly connected to the contact system b) Windings connected to the contact system through a transformer rectifier or chopper without an intermediate circuit
2 Windings not connected to the contact system
AC test: 2 U 2 + 1 000 V with a minimum of
DC test: 3,4 U 2 + 1 700 V with a minimum of 2 550 V
AC test: 10 U 3 with a minimum of 1 500 V and a maximum of 3 500 V
DC test: 17 U 3 with a minimum of 2 550 V and a maximum of 5 950 V
U 1 is the highest voltage to earth which can be applied to the winding when the contact system is at nominal voltage
U 2 is the highest voltage to earth which can be applied to the winding in normal service
U 3 is the highest excitation voltage
NOTE 1 Motors supplied by a transformer/rectifier from an a.c supply or by a chopper from a d.c system are within group 1
The test voltages, including U 1, U 2, and U 3 for alternating voltages, are expressed as root mean square (r.m.s.) values In the case of unidirectional voltages, such as those from pulse control systems, U 1, U 2, and U 3 represent the arithmetic means of the waveforms.
If the winding voltage is not typically referenced to earth, then U₁, U₂, and U₃ should be considered as the maximum voltage that may occur on the winding if any point in its circuit is connected to earth.
When determining \$U_1\$ and \$U_2\$, it is essential to consider the voltage that may arise within the circuit as a result of the control system and the characteristics of the protection devices.
Vibration tests (imbalance)
Each machine must be inspected for vibrations caused by imbalance It is generally sufficient to show that the machine operates smoothly across its entire speed range while on the test bed, with the balancing standard being that it is successfully achieved.
In applications where machine vibration is considered critical, if agreed between user and manufacturer, the test detailed in 8.8 can be carried out on each machine.
Commutator radial run-out measurement
After completing the routine test, a commutator radial run-out measurement should be taken as specified by the user Whenever possible, this measurement should be conducted with an instrument that provides a permanent record of the results.
Radial run-out refers to the variation in height between the highest and lowest points of each bar on the commutator It is essential that these measurements remain within specified limits to ensure optimal performance.
Table 6 and there shall be no abrupt changes in profile
In specific situations, it may be essential to establish lower limits that differ from those listed in Table 6 For certain applications, like low-speed auxiliary machines, acceptable commutation can be achieved with higher run-outs In these instances, modified limits should be mutually agreed upon by the manufacturer and the user.
Table 6 – Limits of commutator radial run-out
Commutator diameter Maximum radial run-out mm
Over 800 mm and all single-bearing or overhung machines
Figure 1a) – Series motor supplied from a contact system
Figure 1b) – Separately excited or compound motor supplied from a contact system
• Type and routine test point
Figure 1 – Commutator type traction motor test points
Figure 2c) – Alternative characteristic test for large alternators
• Type and routine test point
Figure 2 – Main generator test points
A.1 Temperature of the machine parts
Two temperature measurement methods for machine parts will be employed: the resistance method for insulated windings and the electrical thermometer method for commutators, slip rings, and permanently short-circuited uninsulated windings.
Temperature corrections for measured rises are not permitted when the cooling air temperature is between 10 °C and 40 °C during testing However, if the cooling air temperature falls outside this range during a type test, the user and manufacturer may agree on a correction to the measured temperature rises.
Before conducting a short time test, it is essential to verify that the windings are within 4 K of the cooling air temperature using either thermometer or resistance measurements When calculating the temperature rise of the windings, any initial temperature difference of up to 4 K should be adjusted accordingly: subtract from the results if the winding is hotter, or add if it is cooler.
In this method, the temperature rise of the windings is determined by their increase in resistance
For copper windings, the temperature rise at the end of a test is determined by the following formula:
R t R t − = + − + where t 1 is the initial temperature of the winding in degrees Celsius;
R 1 is the initial resistance of the winding at temperature t 1 ; t 2 is the temperature of the winding at the end of the test in degrees Celsius;
R 2 is the resistance of the winding at the end of the test; t a is the temperature of the cooling air at the end of the test in degrees Celsius
NOTE For materials other than copper, the value 235 in the above formula should be replaced with the reciprocal of the temperature coefficient of resistance at 0 °C for the material considered
In this method, the temperature is determined by means of electrical thermometers applied to the hottest accessible spots of the relevant parts immediately after the machine is stopped
A.2 Temperature of the cooling air
For totally enclosed machines lacking external fan ventilation, it is essential to measure the cooling air temperature using at least four thermometers These thermometers should be strategically placed around the machine, positioned between 1 meter and 2 meters away to ensure accurate readings.
The temperature of the cooling air must be measured at its entry point to the machine, and if there are multiple entry points, the average of these measurements should be used.
To ensure accurate temperature readings, thermometers must be shielded from radiated heat and drafts, allowing them to measure the true air temperature surrounding the machine Additionally, it is essential to implement measures that minimize fluctuations in the cooling air temperature to prevent errors.
The cooling air temperature at the conclusion of a test will be determined by averaging measurements taken every 15 minutes during the final hour of a continuous rating test or throughout the entire duration of a short time test.
The initial cold resistance measurement should utilize the same instruments as those used for subsequent hot measurements, without the need for repetition at the start of each test The windings' temperatures will be considered as their surface temperature, as indicated by the thermometer during the resistance measurement, and must not differ from the ambient air temperature by more than 4 K.
To accurately assess the resistance of a winding carrying direct current, it is essential to measure the voltage drop while the machine is in operation These measurements should be taken at regular intervals during the test when the winding is under the test current.
Resistance should be measured promptly after the machine is stopped at the conclusion of the test, utilizing the voltmeter and ammeter method for accurate results.
(volt-amp method), by using a bridge or by other suitable methods, but the same method shall be employed for all readings, including the initial cold one, on a given winding
When using the voltmeter and ammeter method, it is essential to ensure that the current is sufficiently high to achieve the required accuracy without significantly affecting the temperature rise, typically not exceeding 10% of the rated current For measuring armature resistance, the current should be supplied to the commutator via the brushes, and the voltage should be measured between a designated pair of bars located between two brush arms, covering at least half the number of commutator bars per pole.
When utilizing a bridge, voltage probes must be positioned according to the volt-amp method For windings that feature equalizing connections, current probes should be placed at the brush positions next to the voltage probes.