Quick check list of relay 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

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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

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