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Table 12 — Benshaw, Inc. Solid-State Starter Troubleshooting Guide
Problem Probable Causes Area of Correction
AK board phase cor-
rect 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-temper-
ature 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 over-
temperature 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 neces-
sary.
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.