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Table 11 — Benshaw, Inc. Solid-State Starter Troubleshooting Guide
PROBLEM PROBABLE CAUSES AREA OF CORRECTION
AK board phase correct not
on.
1. L1 and L3 switch phases
reversed.
2. Missing phase voltage.
3. Improper line voltage.
1. Switch incoming phases L1 and L3 at top of CD1 or CB1.
2. Check for missing phase voltage.
3. Verify proper line voltage applied against synchronizing transformer
voltage.
AK board relay not on. Ribbon cable not properly
seated.
Check ribbon cable for proper seating. Replace board if necessary.
AK board power
+15 vdc not on.
1. Improper line voltage.
2. Transformer malfunction.
1. Make sure proper line voltage is present at primary synchronizing
transformer.
2. Check synchronizing transformer secondary voltage as follows: On
the BC board, measure from TB11-1 to TB11-2 and TB11-1 to
TB11-3. Both readings should be within 30 to 36 vac. On the BC
board, measure from TB11-1 to TB11-4 and TB11-2 to TB11-4. Both
readings should be within 18 to 24 vac. Replace synchronizing
transformer if voltages are not within the specified tolerances.
1L boards LEDs not on. 1. A short exists between line
and load terminals.
2. An SCR is shorted in the
phase assembly.
1. Remove power and check resistance with ohmmeter.
Locate and remove stray wire strands if required.
2. Remove power. Use ohmmeter to measure the resistance or each
SCR phase assembly from anode to cathode. The reading should
be 50,000 ohm or greater. If not, replace phase assembly.
BC board over-temperature
LED (L3) on prior to run
command.
1. Temperature switch not
functioning properly.
2. BC board not functioning
properly.
1. Disconnect power and check for continuity between TB11-10 and
TB11-11. If no continuity exists, the overtemperature switch is not
functioning properly. Replace defective switch if necessary.
2. Make sure BC board is functioning properly. Replace board if
necessary.
BC board LEDs on prior to run
command.
BC board not functioning
properly.
Board not functioning properly. Replace board, if necessary.
BC board LEDs not on after
run command but before
starter reaches full voltage.
1. Phase assembly malfunction.
2. BC board not functioning
properly.
1. Remove power and check SCRs. Ohmmeter reading of each SCR
gate to cathode resistance at terminals is 8 to 20 ohm. If not,
replace the phase assembly.
2. Replace board, if necessary.
1L board LEDs remain on after
starter reaches full voltage.
Imbalance between phases
exists in motor terminal voltages.
Check for loose SCR gate lead or open SCR gate. Replace phase
assembly, if necessary.
BC board run LED (L5) not lit. BC board not functioning
properly.
Measure 24 vdc at TB11-8 to TB11-4. If voltage is present, replace
board. If not present, replace relay 1CR.
AK board power applied, run
command given, starter at full
voltage, but aux LED not lit.
AK board not functioning
properly.
Replace board.
1L boards LEDs lit. Motor terminal voltage phase
imbalance exists.
Check motor terminal voltages for imbalance between phases. If an
imbalance exists, check for loose SCR gate or open SCR gate.
Replace phase assembly, if necessary.
BC board LED L4 and L5
not lit.
BC board not functioning
properly.
Replace board.
BC board LED L3 lit. 1. FU5 and FU6 fuses not
functioning properly.
2. Phase assembly not
functioning properly.
3. Fan not functioning properly.
1. Check fuses FU5 and FU6. Replace if necessary.
2. Verify that bypass is pulling in by measuring the voltage drop
across the contacts. The reading should be 50 mV or less.
Replace phase assembly, if necessary.
3. Verify fan operation on each phase for 200 amp units. Replace
fan, if necessary.
BC board L2 lit. SCR phases not functioning
properly.
Measure resistance from anode to cathode for each SCR phase
assembly. Replace shorted phase, if necessary.
BC board L1 lit. Motor lead grounded. Megger motor to test for motor lead going to ground.
Start command given. Motor does not begin rotation. Turn ‘Starting Torque’ potentiometer RV2 clockwise until motor
rotation begins.
Motor does not reach full
speed within 25 seconds.
Ramp up setting is not correct. Turn ‘Ramp’ potentiometer RV1 counterclockwise. Restart motor
and verify that motor reaches full speed within 25 seconds.
115 vac missing from LL1
and LL2.
1. CB2 is not on.
2. Fuse no. 4 (FU4) blown.
1. Verify CB2 is on.
2. Check FU4 for continuity. Replace, if necessary.
SMM not responding. 1. CB4 is not on.
2. Potentiometer RV1 needs
adjustment.
1. Verify CB4 is on.
2. Adjust potentiometer RV1 for 24 vac at SMM terminals J3-23 and
J3-24.
LEGEND
AK — Vendor Board Designation
BC — Vendor Board Designation
CB — Circuit Breaker
CD — Disconnect Switch
CR — Control Relay
FU — Fuse
LED — Light-Emitting Diode
L1, L3 — Terminal Board
LL1, LL2 — Control Power Terminals
RV1 — Line Voltage Signal Calibration
SCR — Silicon Control Rectifier
SMM — Starter Management Module
TB — Terminal Board
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