If one of the voltages is higher than 2 v, but the voltages of the 3 power poles are
approximately equal, the starter is probably still in current limit. If the voltage is higher than 2 v
on only 1 or 2 power poles, not all SCRs are firing properly. Make sure the gate lead
connections are tight. If all 3 power poles have less than a 2 v drop from line side to load side of
each starter power pole when the motor is up to speed, any current unbalance in the motor is
caused by the motor or an unbalanced line voltage.
Electronic Protection Relay (EPR)
On Cutler-Hammer solid-state starters, the EPR is designed to provide an alternative to
conventional motor protection due to overcurrent. See Figure 50. It performs the following
functions:
Test Button
— The TEST button provides testing of the EPR’s ability to detect overload, test
relay operation, and simulate motor load.
Click here for Figure 47 — Resistance Check
Click here for Figure 48 — SCR and Power Poles
Click here for Figure 49 — Typical Cutler-Hammer® Solid-State Starter
(Internal View)
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