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How To Choose An Electromagnetic Relay ?

Part Numbering System

Our relays part numbering systems:

Amount of contacts - Main title – Current of contact – Serial Number/Environmental Rating – Input Voltage – Type of Installation – Failure Rate

This system is according to “Relays part numbering system of electronic equipment” set up by primary Aerospace Industry Standard QJ546-89 (China).

Notes:

• Amount of contacts consists of digit.
• Main title said the main feature of the relay, consists of two letters – first letter is settled with “J” while second letter said the type of relay; Both are based on Chinese words.
• Current of contact consists of digit, said the current of relay main contact rated resistive load.
• Serial Number is settled by manufacturers with digit.
• Environmental Rating consists of five levels with Roman numerals according QJ546-89 and , which are Ground Equipment (I), Satellite and Missile (Normal condition II; Special class III, IV, V). Details see below:

	Item		Level	I	II	III	IV	V
1	Ambient Temperature		℃	-55~85				-65~125
2	Relative Humidity			When +40℃, 90%~95%
3	Atmospheric Pressure		Pa	1x105~266		1x105~1.3
4	Sinusoidal Vibration		Hz	10~500	10~2000			10~3000
			m/s2	100	150		200	300
5	Impact		m/s2	300	500	750		1000
			ms	11	11	6		6
6	Constant Acceleration		m/s2	200	500	750		1000
7	Collision		m/s2	250   4000 times			400   4000 times
81)	Vacuum Hot Soak		Pa		+55℃ 1.3x10-3~1.3x10-4
91)	Vacuum Cold Soak		Pa		-40℃ 1.3x105~1.3x10-4
101)	Vacuum Cold Welding		Pa		1.3x10-7remove the shell
111)	Particle Radiation	Proton	MeV		Energy Level J>0.01
			1/cm2d		Integrated flux2.8x1011~2.4x1012
		Electron	MeV		Energy Level J>0.1
			1/cm2d		Integrated flux1.5x1012~1.9x1012
121)	Noise		dB		50Hz~10KHz, 140~160

Note: 1) means Special environmental conditions

• Input Voltage said the nominal value of relay coil excitation voltage.
• Type of Installation , there are five types of installation.
  • A - Welding directly
  • B - Horizontal plate
  • C - Vertical
  • D - Nut mounting
  • E - Horizontal PCB soldering installation

For example,

How To Choose

When choosing an Electromagnetic Relay, you will consider the quantity, price and delivery; besides these economic factors, you may need to pay more attention to actual use requirements and do as it. First, please make sure what kind of electromagnetic relay you need, then fix the part number carefully by following below three requirements of features and physical characteristics.

1. Requirements of environmental Adaptability

For the item of environmental adaptability, you may need to define the level of environmental adaptability, test method and cycling time, installation type and status during test, failure criterion. Etc. Specific including:

a) Mechanical stress – vibration, impact, centrifugal acceleration, etc.

b) Atmospheric Environmental Stress – temperature, humidity, Atmospheric pressure, etc.

c) Special environmental stress - Vacuum hot and cold soak, Vacuum cold welding, radiation, Salt spray, mold, oil mist, electromagnetic interference, transient, etc

2. Main parameters of necessary features and performance

a) parameter of input (parameter of control the wilding groups) - coil resistance（or power consumption）rated coil excitation voltage（current）, fluctuation range, operation type, etc.

b) parameter of output (parameter of control the wilding groups) - number of contact group, open/breaking voltage, working mode, the kind of load, contact voltage drop (contact resistance), etc. (power frequency of output current defaults to 400Hz. Please contact us for technical support if any power frequency change. )

c) parameter of time – time of picking/releasing, contact bounce, etc.

d) safety guideline - insulation resistance, dielectric strength, etc.

e) lifetime of contact and guideline of its failure rate.

f) the failure mode when it is necessary to remove or suppress.

3. Parameters of physical characteristics

Volume, quality, dimension, installation type, number of contact group, type of output port, shell is grounded, hermetical, etc.

Please search for the product according your demand of features and physical characteristics. If you are not able to find out the right one, you are welcomed to contact us for new product task or make some agreement of advancement, OEM, etc.

General Notes

a) please make sure you have offered the right part number when you enter your order.

b) For some special environment, we would like to insist that an agreement need to be singed or proper test needed to be made before both us confirm the order.

c) When encountered non-resistive load or low load, we would like to insist that an agreement need to be singed or proper test needed to be made before both us confirm the order.