Quick check list of relay failure causes

- Dec 20, 2019-

Quick check list of relay failure causes


Refer to the following table for failure phenomena, possible failure modes and causes of relays.

Failure phenomenon

Failure mode

Failure causes

Relay does not operate

No voltage at coil end

-Open circuit of power supply line

-Circuit wiring error or short circuit condition

-Poor welding of lead out foot

Insufficient voltage at coil end

-Low supply voltage

-Power cord too long

-The voltage specification of the selected relay is too high

The coil is blocked

-Poor welding

-Coil disconnection

Relay failure


-Falling, or under strong impact

-Contact failure

The polarity of the voltage at the coil end of the polarization relay is not correct

-The transportation process is impacted and the state changes

-Circuit wiring error

Relay does not release

Residual voltage at coil end is too high

-Influence of other energy storage elements on coil end

-Leakage current or bypass current on the coil

-Residual voltage of semiconductor circuit is too high

Relay failure

-Falling, or under strong impact

-Contact failure

Unstable relay operation

Unstable power supply


-Too large power ripple

-Under voltage

-Coil resistance out of tolerance

Unstable relay parameters

-Falling or strong impact

-Coil turn to turn short circuit

Relay misoperation

-Whether the control procedure is wrong

-Excessive vibration in service environment

NC or NO contact sticked

Overcurrent

-Too much load

-Excessive surge current

Abnormal contact jitter

-Large external vibration

-AC relay does not work stably and there is a beep

-Unstable relay action

Relay action frequency too high

--

High ambient temperature

The number of times the relay has been used has exceeded the expected life

No contact NC contact not picke-up

Contact resistance is too high

-Poor welding

-Foreign matter between contacts

-The contact is oxidized or vulcanized due to the poor service environment

No current at contact end

-Load line open circuit

-Circuit wiring error or short circuit condition

-Poor welding of lead out foot

The number of times the relay has been used has exceeded the expected life

--

Note: in case of relay failure, if you still have some unclear points after preliminary analysis, please contact MEISHUO for analysis.