Card Cage - Hobart POWER MASTER Operation And Maintenance Manual With Illustrated Parts List

OM-2065 / Operation and Maintenance Manual
90SB51 / Spec. 7015-3 / Frequency Converter
2. Procedure for Restoring Unit to Operation After a Fault
Fault shutdowns are indicated on ALARM I, II and III. Following a fault shutdown of the unit, the fault
alarm is reset by pushing the STOP/RESET button on the control panel. The unit can be restarted by
pushing the START button on the control panel, however, other adjustments and corrections may be
necessary as noted below.
a. UV- Undervoltage Fault
If an undervoltage fault shuts the unit down (indicated by UV light on ALARM II), disconnect the
load, reset the alarm, and restart the unit. Check the output voltage on the panel voltmeter to see
that the reading is normal. If the reading is low, attempt to adjust the voltage with the VOLTAGE
potentiometer on the AMP card. If there is no response to rotation of the potentiometer, replace the
AMP card and repeat the test.
b. OV- Overvoltage Fault
If an overvoltage fault shuts the unit down (indicated by OV light on ALARM II), disconnect the load
and restart the unit after resetting the alarm. Check the output voltage. Since response to an
overvoltage condition is instantaneous, there may not be time to read output voltage on the panel
voltmeter. Attempt to adjust the voltage downward by turning the potentiometer, on the AMP card,
counterclock-wise. If no effect is seen, replace the AMP card. Since any interruption in the feedback
loop will have the same effect as an overvoltage condition, there is a chance that the fault could be
in the voltage feedback transformers or in a broken wire connecting the feedback transformers to
the AMP card.
c. OC (SH)- Overcurrent (Short) Fault
When alarm indicator light OC (SH) on ALARM II comes on, this indicates that a short circuit on the
output has occurred. A short circuit is here defined as an overload exceeding 200% of maximum
current rating for the converter. Disconnect load and restart unit after resetting the alarm.
Chapter 3-1
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Card Cage

Figure 2
Nov 01/90