INTERNATIONAL STANDARD IS0 5867 l Fi rst ed i t i on 1 996 02 01 Aircraft Electromagnetic relays and contactors Part 1 General requirements ABronefs Relais et contacteurs &ectromagn&iques Partie I Exi[.]
Detail specification sheets
Individual item requirements must adhere to the specifications outlined in this part of ISO 5867 and the corresponding detail specification sheets In case of any discrepancies between the general requirements and the detail sheets, the specifications in the detail sheets will take precedence, ensuring clarity and compliance.
The manufacturer shall prepare an individual specifi- cation sheet for each type of device produced The
IS0 5867-1 :1 996(E) 0 IS0 individual specification sheet shall define the values for parameters given in annex A.
Temperature class
The temperature classes which define the maximum and minimum temperatures for use shall be as fol- lows:
Sealing
Enclosure design shall be classified as follows:
Altitudes
Class 1 and 2 sealed relays and contactors shall be suitable for use up to an altitude of 25 000 m
Class 3 contactors shall be suitable for use up to an altitude of 1 5 000 m.
Dimensions
Relay and contactor dimensions shall be as defined in the detail specification sheet (see 4.1 ).
Design requirements
The relays and contactors shall operate satisfactorily when mounted in any attitude The size and mass shall be the minimum compatible with the required performance, reliability and strength
The relays and contactors shall be of the single-pole or multi-pole (main contacts) type, with or without auxiliary contacts
The auxiliary contacts shall be mechanically linked to the main contacts and shall indicate the position of the main contacts
Suitable barriers shall be placed between the ter- minals of the contactors in order to prevent an acci- dental short-circuit These barriers shall be sufficient to prevent the short-circuiting of all the terminals through the presence of a flat conducting part
The coil of the relay or contactor shall operate from either, but not both, a 28 V d.c or 1 1 5 V a.c., 400 Hz system having the characteristics specified in IS0 1 540
The contacts of relays or contactors shall be capable of switching 28 V d.c and/or 1 1 5 V/200 V a.c.,
400 Hz having a system characteristic specified in IS0 1 540.
Sealing enclosures
Sealing enclosures must possess adequate mechanical strength to endure handling, transit, storage, and installation without malfunction or distortion Additionally, the enclosure should not be part of the electrical contact or coil circuit to ensure safety and proper operation.
NOTE 1 The case may be a part of the magnetic circuit 4.7.1 Hermetically sealed enclosures
Hermetically sealed enclosures shall be constructed as a gastight enclosure that has been completely sealed by fusion of glass or ceramic to metal, or bonding of metal to metal Hermetically sealed relays and contactors shall be purged of all air Relays shall be filled with a suitable inert gas The fill gas shall have a dew point of at least 5 “C below the lowest temperature rating of the device
NOTE 2 Contactors may be filled with air or with inert gas
To ensure compliance with environmental sealing standards, enclosures must be constructed using methods other than those outlined in section 4.7.1 to meet the specified degree of seal as detailed in the project specifications Environmentally sealed relays and contactors should be thoroughly purged of all air and filled with a suitable inert gas to prevent moisture ingress The inert fill gas must have a dew point at least 5°C below the lowest operating temperature of the device, ensuring reliable performance in harsh environmental conditions Proper sealing and inert gas filling are critical for maintaining the durability and functionality of electronic components in demanding environments.
NOTE 3 Contactors may be filled with air or with inert gas
Ventilated contactors must be fully enclosed to ensure mechanical protection, dust resistance, and explosion-proof operation The enclosure should allow the contactor to operate seamlessly even after removing the cover, with a design that prevents pressure differentials that could promote moisture buildup The cover should be rugged, made from high-impact materials, and securely attached to ensure durability and safety.
Installation clearances
Adequate clearance shall be provided for installation of terminals and mounting hardware Clearance for standard socket wrenches shall be provided Special installation tools shall be avoided where possible
The mounting shall provide an effective electrical contact to ground when the relay or contactor is mounted
Metal covers shall be provided with a means for grounding Relays and contactors shall have electrical terminals as specified in the detail specification (see
No rotation or other loosening of a terminal shall occur throughout the relay or contactor life
Power terminals of greater than 25 A rating shall be of the threaded stud type Terminals rated at 25 A or less may be plug-in, solder hook, stud or screw ter- minals
4.1 0.1 1 Threaded terminals and mounting studs
Stud terminals are designed to accept connections using crimped type lugs made of copper or aluminium, or copper bars for reliable electrical contact Each terminal should be secured with a flat washer, with a diameter at least equal to the base of the terminal, to ensure proper load distribution A self-locking nut or a standard nut combined with a suitable locking washer must be used on each terminal to ensure secure and vibration-resistant connections Proper connection methods using these components are essential for maintaining electrical safety and performance.
No rotation or other loosening of a terminal, or any fixed portion of a terminal, shall be caused by any mechanical forces specified in table 1 involved in the connection or disconnection, throughout the life of the relay or contactor
These are maximum values which shall not be ex- ceeded
NOTE 4 For installation torque values, see the detail specification (4 I)
Table 1 - Strength of threaded terminals (static value of pull and torque) Thread size
No IO-24 UNC l/4-28 UNC 5/l 6-24 UNF 3/8-24 UNF 7/l 6-20 UNF l/2-20 UNF
Each terminal must be equipped with a terminal seat that ensures a reliable current-conducting path, built to handle specified electrical loads The diameter of the seat should be at least large enough to prevent current density from exceeding 1.55 x 10^6 A/m² (1,000 A/in²), ensuring safe and efficient operation Proper sizing of the terminal seat is essential for maintaining electrical safety and preventing overheating in electrical installations.
NOTE 5 The seat does not include the cross-sectional area of the stud
Stud terminals must be designed to accommodate two lugs with the specified hardware, ensuring secure connections At least 1.5 threads should remain visible above the nut once all parts are properly tightened, promoting safety and reliability Proper installation of stud terminals is essential for optimal electrical performance and compliance with industry standards.
4.1 0.1 2 Solder hook or straight terminals
Solder terminals shall be tin plated The terminal de- sign shall allow for at least two wires of relay rating to be connected (see 4.1 )
Plug-in terminals shall conform to the arrangement and dimensions necessary for proper mating with the associated socket or connector
For plug-in relays, the mounting design must ensure that the entire relay weight is supported independently of the electrical terminals, with stability provided by an auxiliary mounting means It is essential that relays with plug-in terminals undergo electrical and environmental testing with the specified socket assembled to the unit Additionally, plug-in terminals should be gold plated to ensure reliable electrical contact and durability.
Screw terminals must be supplied with the specified hardware outlined in the detailed specifications (see 4.1) The seat diameter should be equal to or greater than the diameter of the corresponding lug designed for the specific current Additionally, its area must be sufficient to prevent the current density from exceeding 1.55 x 10^6 A/m² (1,000 A/in²), ensuring safe and reliable electrical connections.
NOTE 6 The seat area does not include the cross- sectional area of the stud
Terminal identification must be durably and clearly marked according to the specifications in tables 2 to 4 For dual coil relays, the connection details between the coils and contacts are outlined in table 5 The positive end of the coil (XI) should be distinctly identified on the header using a contrast bead for easy recognition.
Table 2 - Contact arrangements, svmbols and terminal marking
Form “C” Form “K” normally closed (two position) three position centre off
NOTE - Contacts are shown with coil(s) de-energized
Normally open Normally closed Change over
Table 4 - Symbols and marking for terminals
Single coil terminals Dual coil terminals
Relays and contactors equipped with stud or screw terminals must feature appropriate coverings or separation measures to ensure the protection of terminal parts This is essential to prevent accidental short circuits, grounding issues, or contact by personnel, thereby enhancing safety and compliance with electrical standards.
Terminal covers and barriers must be engineered to meet specific performance standards for relays and contactors, ensuring reliable operation Enclosures should allow the relay or contactor to function properly without any adjustments when the cover is removed Additionally, cover designs must prevent pressure differentials between the interior and exterior, maintaining safety and system integrity.
NOTE 7 Barriers may be removable, or may be integral with removable covers
Contact arrangements, symbols and terminals mark- ing shall be in accordance with tables 2 to 4
Materials must conform to the requirements outlined in sections 4.1.2.1 and 4.1.2.2 of ISO 5867, ensuring compliance with specific standards When no specific material is designated, the manufacturer has the discretion to select suitable materials The chosen materials should enable relays and contactors to meet the specified performance criteria and product characteristics, ensuring reliable and standards-compliant operation.
Metals used in electrical components must be corrosion-resistant and properly plated or treated to prevent deterioration Specifically, zinc, cadmium, or unfused pure tin plating should not be applied to internal parts of hermetically sealed relays and contactors, ensuring reliable performance and longevity in demanding environments Proper corrosion protection is essential for maintaining the integrity and safety of electrical equipment.
Unless otherwise specified in the detail specification (see 4.1 1 , the use of dissimilar metals shall conform to table6
4.1 2.2 Non-metals Non-metals, including protective finishes, shall a) be moisture-resistant; b) be non-toxic; c) be arc-resistant; d) be flame-resistant; e) be self-extinguishing; f) not support fungus growth
They shall not be adversely affected by loss of char- acteristics of composition in aircraft fluids at the tem- peratures specified in 4.2
Materials in hermetically sealed envelopes are not re- quired to meet the moisture- and fungus-resistance requirements
Hot-dip-zinc plate; galvanized - 1 ,05 1 20 steel
Zinc, wrought; zinc-base die-casting - 1 ,lO 1 25 alloys; zinc, plated
Magnesium and magnesium-base - 1 ,60 1 75 alloys, cast or wrought (most 0 anodic)
1 ) Comoatible coudes: Potential difference of 0.25 V max between grouts
4.1 2.2.1 Plastic material 5 Performance detail requirements
Plastic material shall conform to 4.1 2.2 In addition, when subjected to any of the tests in this part of
ISO 5867 specifies that plastic materials must not support combustion or emit noxious gases in harmful quantities Additionally, these materials should not release gases in quantities that could cause an explosion within a sealed housing, ensuring safety and compliance with hazardous environment standards.
1 ) cause contamination of the contacts or other parts of the component,
2) form current-carrying tracks when subjected to arcing conditions
Ceramic insulating material shall conform to the detail specification (see 4.1 and 4.1 2 2) External ceramic surfaces shall be glazed
Magnet wire shall conform to the detail specification
Rubber shall conform to the detail specification (see
Semiconductors shall conform to the detail specifi- cation (see 4.1 )
Relays and contactors manufactured according to ISO 5867 must undergo rigorous testing and meet the qualification inspection criteria outlined in section 7.2 Only products that pass these quality assessments, produced using certified production tools, are qualified for use Ensuring compliance with these standards guarantees reliability and performance in their applications.
Relays and contactors supplied in accordance with ISO 5867 Part 8 can be qualified by similarity to other relays or contactors within their generic family This qualification process may necessitate additional testing to ensure compliance and performance consistency across similar devices.
When relays or contactors are examined and tested in accordance with 6.1 , they shall conform to require- ments for materials, design, construction, physical di- mension, weight, item marking and workmanship as specified in this part of IS0 5867 and in the detail specification (see 4 I)
5.1 1 Dimensions Dimensions shall be in accordance with 4.5
5.1 2 Header glass of hermetically sealed enclosures