Chatter describes contacts that bounce in and out because coil voltage is hovering near pickup, the coil supply is low or distorted, a measured value sits right at a relay setting, or vibration shakes the armature. It burns contacts, floods the alarm list and can set breakers pumping. Fixes include restoring proper coil voltage, adding hysteresis or a time delay, and cleaning pole faces or replacing broken shading rings on AC contactors.
Contactor chatters every time the compressor starts, the supply sags to 170 volts and the coil can't hold in.
Also heard as
- contact chatter
- relay chatter
Related terms
Pickup
Threshold at which a protection element starts to operate, and the moment the measured value crosses it.
Sag
Brief drop in RMS supply voltage, usually to between 10 and 90 percent of nominal, lasting up to about a minute.
Kick
Shop verb for a breaker, overload or relay tripping, as in the breaker kicked.