Carrier PC211 Start-Up, Operation And Maintenance Instructions Manual page 307

Table 13 — Cutler-Hammer Solid-State Starter Troubleshooting Guide
Problem
CB trips (electrically
operated disconnecting
means opens) as it is
closed.
CB trips while motor is
running.
CB trips when STOP is
pressed.
Starter does not pick up
and maintain.
Starter maintains but
motor does not acceler-
ate or does not attain
full speed (stalls).
Insufficient Torque.
Motor accelerates too
slowly.
Probable Cause
Motor is not connected.
Incorrect phase sequence to the starter, 3-
phase power not connected, or terminal
loose.
Shorted SCR.
Shunt trip contact between terminals closes
due to shorted SCR.
Shunt trip latching relay not reset (if used).
Microprocessor detected non-standard
operation.
Voltage drop across SCR (looks like
shorted SCR).
Line voltage is not applied.
Overload is not reset.
120 v control voltage is not present.
Heatsink overtemperature switches are
open.
Current limit is too low.
Improper current feedback.
High breakaway torque required.
Current limit is too low.
Ramp time is too long.
Broken current feedback resistor.
Area of Correction
Connect motor to starter.
Switch two incoming power leads. The 50
and 51 corresponding motor leads must
also be switched to maintain the same
motor rotation.
Perform shorted SCR check.
Perform shorted SCR check.
Reset STR relay by pushing RESET but-
ton on relay.
Check wiring to logic module or replace
logic module.
Check SCR.
Check incoming lines for proper voltage.
Reset overload.
Check control transformer fuse. Check
control circuits.
Check for continuity through overtemper-
ature switches. Check that all fans are
rotating freely. Check for excessive motor
current draw.
Increase current limit setting clockwise.
Set ramp time to minimum (counterclock-
wise).
Check current feedback resistor for
proper calibration.
Load is not suitable for reduced voltage
starting.
Increase current limit setting clockwise.
Decrease ramp time setting counterclock-
wise.
Check by recalibrating CFR.