1
Low control voltage
CheckMeasure coil voltage while attempting pull-in. Must be ≥85% of rated.
FixCheck transformer, control wiring length, dropping resistors.
2
Pitted / welded tips
CheckVisual; measure mV drop across closed tips.
FixReplace tips or contactor.
3
Undersized contactor for FLA
CheckVerify NEMA/IEC rating ≥ motor FLA.
FixUpsize.
4
Loose terminations causing arcing
CheckIR camera; torque check.
FixRe-torque to spec.
Safety
Lockout/tagout before opening enclosures. Verify zero energy. Bleed system pressure before opening any pneumatic connection.