Carrier 19XL Start-Up, Operation And Maintenance Instructions Manual page 84

Table 11 — Benshaw, Inc. Solid-State Starter Troubleshooting Guide
PROBLEM
AK board phase correct not
on.
AK board relay not on.
AK board power
+15 vdc not on.
1L boards LEDs not on.
BC board over-temperature
LED (L3) on prior to run
command.
BC board LEDs on prior to run
command.
BC board LEDs not on after
run command but before
starter reaches full voltage.
1L board LEDs remain on after
starter reaches full voltage.
BC board run LED (L5) not lit.
AK board power applied, run
command given, starter at full
voltage, but aux LED not lit.
1L boards LEDs lit.
BC board LED L4 and L5
not lit.
BC board LED L3 lit.
BC board L2 lit.
BC board L1 lit.
Start command given.
Motor does not reach full
speed within 25 seconds.
115 vac missing from LL1
and LL2.
SMM not responding.
AK — Vendor Board Designation
BC — Vendor Board Designation
CB — Circuit Breaker
CD — Disconnect Switch
CR — Control Relay
FU — Fuse
LED — Light-Emitting Diode
PROBABLE CAUSES
1. L1 and L3 switch phases
reversed.
2. Missing phase voltage.
3. Improper line voltage.
Ribbon cable not properly
seated.
1. Improper line voltage.
2. Transformer malfunction.
1. A short exists between line
and load terminals.
2. An SCR is shorted in the
phase assembly.
1. Temperature switch not
functioning properly.
2. BC board not functioning
properly.
BC board not functioning
properly.
1. Phase assembly malfunction.
2. BC board not functioning
properly.
Imbalance between phases
exists in motor terminal voltages.
BC board not functioning
properly.
AK board not functioning
properly.
Motor terminal voltage phase
imbalance exists.
BC board not functioning
properly.
1. FU5 and FU6 fuses not
functioning properly.
2. Phase assembly not
functioning properly.
3. Fan not functioning properly.
SCR phases not functioning
properly.
Motor lead grounded.
Motor does not begin rotation.
Ramp up setting is not correct.
1. CB2 is not on.
2. Fuse no. 4 (FU4) blown.
1. CB4 is not on.
2. Potentiometer RV1 needs
adjustment.
LEGEND
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
AREA OF CORRECTION
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.
Check ribbon cable for proper seating. Replace board if necessary.
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.
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.
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.
Board not functioning properly. Replace board, if necessary.
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.
Check for loose SCR gate lead or open SCR gate. Replace phase
assembly, if necessary.
Measure 24 vdc at TB11-8 to TB11-4. If voltage is present, replace
board. If not present, replace relay 1CR.
Replace board.
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.
Replace board.
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.
Measure resistance from anode to cathode for each SCR phase
assembly. Replace shorted phase, if necessary.
Megger motor to test for motor lead going to ground.
Turn 'Starting Torque' potentiometer RV2 clockwise until motor
rotation begins.
Turn 'Ramp' potentiometer RV1 counterclockwise. Restart motor
and verify that motor reaches full speed within 25 seconds.
1. Verify CB2 is on.
2. Check FU4 for continuity. Replace, if necessary.
1. Verify CB4 is on.
2. Adjust potentiometer RV1 for 24 vac at SMM terminals J3-23 and
J3-24.
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