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How misuse of contactor result in Coil Durability (endurance) ?

Aging is accelerated when operational condition environment stress etc. is more than normal

operational condition. Endurance decrease of coil or main cause of burnout are shown


• Insertion fault

Coil is burned out by excitation rush current (10~15 times of holding current) flowing into the coil,

if you opperate it continuously without perfect inhalation after the power voltage decrease abnormal material penetrates

into magnetic contact pole.

• Overcurrent

Excitation current increases when permitted voltage is too high for coil and, the coil endurance is reduced. In case of high

current,coil will sometimes burn out.

• Application mistake of voltage and frequency

It can be cause of coil burnout when coil rated voltage is higher or lower than the power voltage.

Coil is burnt out when frequency application is wrong in case of coil which has middle tap of terminal three or terminal four.

• Excessive switching frequency

It can be the cause of burnout when it is used more than designated on/off frequency.

• Closing installation

Heating emmitance installation is accellerated for heating aging by the central coil is the highest temperature when magnetic

switch is used at continuous flow current.

• Chattering

If contact point has severe chattering by control voltage variation or coil terminal release, it causes coil burnout by drive current flowing into the coil.

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