TECH TIP
TECH TIP
Contactor Trouble Shooting
David Duckworth
David Duckworth is the Director of Training and Development at Commercial Kitchen Parts & Service in San Antonio , Texas .
THERE are two types of noises Electro mechanical contactors make that require two different repair solutions .
“ Chattering contactor ” - The movable contact bar will not stay engaged with the stationary contacts . It is pulling in and releasing rapidly multiple times .
The problem lies within the control circuit supplying voltage to the contactor coil . Some examples of these are :
a ) Lower voltage supplied to the coil than it is rated for b ) An intermittent drop in the supply voltage c ) Slow opening and closing contacts on a solid state control board d ) Door reed switches that are failing
This is the area you will need to trouble shoot . You do not have to replace the contactor in this case unless there are other signs of wear .
“ Buzzing contactor ” - The movable contact bar is pulled in to the stationary contacts , but the coil is struggling to hold the contact bars armature down causing the contactor to buzz .
The problem is the contactor itself . It is simply wearing out . The only solution is to replace the contactor . Be sure to use the correct rated contactor when replacing .
FLA = full load amperage for motor duty only .
Resistive = full load amperage for none motor applications . e ) Loose wire connections
SPRING 2016
8