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 L 1 and L3 at top of CD1 or
CB1.
2. Check for missing phase vol tage.
3. Verify proper line volta ge applied against syn chronizing
transformer voltage.
AK board relay not on. Ribbon cable not properly
seated. Check ribbon cabl e for proper seating. Rep lace board if
necessary.
AK board power +15
vdc not on. 1. Improper line voltage.
2. Transformer
malfunction.
1. Make sure proper line volt age is present at prim ary
synchronizing transformer.
2. Check synchronizing transformer secondary voltage as
follows: On the BC boar d, measure from TB11-1 t o
TB11-2 and TB11-1 to TB11 -3. Both readings shou ld
be within 30 to 3 6 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 transform er 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 wi re strands if required .
2. Remove power. Use ohmm eter to measure the
resistance or each SCR phase assembly from anode to
cathode. The reading shou ld be 50,000 ohm or greater.
If not, replace phase ass embly.
BC board over-temper -
ature LED (L3) on
prior to run comm and.
1. Temperature switch not
functioning properly.
2. BC board not
functioning properly.
1. Disconnect power and check for continuity betw een
TB11-10 and TB11-11. If no continuity exists, the ov er-
temperature switch is not functio ning properly. Replace
defective switch if necess ary.
2. Make sure BC board is fun ctioning properly. Repl ace
board if necessary.
BC board LEDs on
prior to run comm and. BC b oard not functioning
properly. Board not func tioning 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 readi ng of
each SCR gate to cathode r esistance at terminals is 8
to 20 ohm. If not, replace the phase assembly.
2. Replace board, if necessa ry.
1L board LEDs remain
on after starter reaches
full voltage.
Imbalance between phases
exists in motor terminal
voltages.
Check for loose SCR gate l ead or open SCR gate.
Replace phase assembly, if necessary.
BC board run LED
(L5) not lit. BC b oard not functioning
properly. Measure 24 vdc a t TB11-8 to TB11-4. If vo ltage is present,
replace board. If not p resent, replace relay 1CR.