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OM-2065 / Operation and Maintenance Manual
90SB51 / Spec. 7015-3 / Frequency Converter
Section 2. Troubleshooting Charts
Fault Indicators
Trouble, Sympton and Condition
1. Input circuit breaker will not
stay on
2. UV- Undervoltage on ALARM II
3. OV- Overvoltage on ALARM II
4. OC(SH)- Overcurrent/Short
Circuit on ALARM II
5. OC 125%- Overcurrent by
125% on ALARM II
6. OC 150%- Overcurrent by
150% on ALARM II
CAUTION
Nov 1/90
Probable Cause
a. Front or rear door open
b. Door safety switch(s) not
functioning (not depressed)
c. Shorted input rectifiers.
a. Misadjustment on AMP
card or faulty AMP card.
a. Misadjustment on AMP
card.
b. Faulty AMP card
c. Faulty voltage feedback
transformers (T7, T8, T9) or
open interconnecting wires
from these transformers to
card cage connection.
a. Short circuited outputs
(Phase to phase or phase
to neutral) more than 200%
overload.
a. Load exceeds 125% of
rated current more than 5
minutes.
a. Load exceeds 150% of
rated current more than 10
seconds.
When the unit is connected to AC input, dangerous voltages are present inside
the unit. Turn off input power and disconnect output cable from aircraft. Check
to be sure that no voltage remains on DC filter capacitors before attempting any
repairs inside the unit.
Test, Check, And Remedy
Close door(s).
Check switch(s) for circuit
breaker shunt trip operation.
Adjust if needed.
Test input rectifiers with
suitable voltohm meter.
Replace ifnecessary. (Observe
torque values in Section 2-1).
Adjust VOLTAGE up. (See
para. 2, A) on procedure for
restoring to operation.
Adjust VOLTAGE down. (See
para.2, B on procedure for
restoring to operation).
Replace, (See para.2B on
restoring to operation).
Replace transformer and/or
repair wires.
Remove short or reduce load,
(See para.2C on restoring to
operation).
Normal safeguard, reset and
operate. (See para.2, D on
procedure for restoring to
operation).
Normal safeguard, reset and
operate. (See para.2, E on
procedure for restoring to
operation).
Chapter 3-2.
Page 1
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