If one of the voltages is hi ghe r than 2 v, but the voltages of th e 3 power poles are
approximately equal, the starter is probably st ill in current limit. If the v ol tage is higher than 2 v
on only 1 or 2 power poles, not all S CR s are firing properly. Ma k e s ur e t he gate lead
connections are ti ght. If all 3 power po les have less than a 2 v drop from line sid e to load side of
each starter power pole wh en the motor is up to speed, any c ur r e nt unbalance in the motor is
caused by the motor or an un bal anced line voltage.
Electronic Protection Relay (EPR)
On Cutler-Hammer soli d- s t ate starters, the EPR is de signed to provide an alter na tive to
conventional mot or protection du e to overcurre nt. See Figure 50. It performs the following
functions:
Test Button
— The TEST button provides test ing of the EPR’s ability to det ec t overload, test
relay operation, and simulate mo tor load.
Click here for Figure 47 — Resistance Check
Click here for Figure 48 — SCR and Power Poles
Click here for Figure 49 — Typical Cu tler-Hammer ® Solid-State Starter
(Internal Vi ew)