Hobart 6T28-600CL Operation And Maintenance Manual page 41

OM-2244 / Operation and Maintenance Manual
DCS-600/ Series 500082 / Solid State Transformer-Rectifiers
Trouble, Symptom, Condition
Output Voltage Not Proper Level
1. Poor voltage regulation
2. Output voltage too high (above
32 Volts)
3. Unstable voltage
Trouble, Symptom, Condition
Output Contactor Fault
1. Output contactor will not close.
December 15, 2014
Probable Cause
a. Loose connection of voltage
sensing lead
a. Voltage calibration off
b. Voltage sensing lead open
a. Open filter capacitor
b. One or more SCRs not firing
properly
Probable Cause
a. Defective output switch (S2)
b. Defective input contactor
auxiliary contacts (K1)
c. Defective output voltage select
switch (S103) (if applicable)
Test, Check, and/or Remedy
Check connection at output
contactor and control circuit board.
Tighten connection as necessary.
Attempt calibration per Section 2-2. If
calibration isn't possible replace PC
control board.
Repair or replace voltage-sensing
lead.
Find and replace defective capacitor.
Adjust balance control or replace
defective SCR heat sink assembly if
oscilloscope shows faulty SCR
devices. Replace PC control boards
if oscilloscope shows no gate pulse
and the PC control board inputs and
controls are proper except for output.
Test, Check, and/or Remedy
With the unit turned off, place a
jumper between terminals 2 and 4 on
S2. Turn S1 on. If output contactor
closes, S2 is defective. Replace.
With the unit turned off, place a
jumper between terminals NO 1 and
COM 3 on input contactor. Turn S1
on, and place S2 in Close position.
If output contactor closes, K1 is
defective. Replace.
With the unit turned off, place a
jumper between terminals 4 and 5 on
S103. Turn S1 on, and place S2 in
Close position. If Output contactor
closes, S103 is defective. Replace.
Chapter 2-1
Page 9