UFC 3-570-06
JANUARY 31 2003
rectifier with a handheld multimeter on the AC volts scale. Measure voltage from F6 to
C6 (tap bars). One of two conditions may exist: voltage may be near zero (proceed to
paragraph 5-2.5.1), or near normal (proceed to paragraph 5-2.5.2).
5-2.5.1
Voltage Near Zero. This indicates loss of AC power to the rectifier, bad
fuses or circuit breakers, or a bad transformer (or connections) in the rectifier (proceed
to paragraph 5-2.6).
5-2.5.2
connections inside the rectifier (proceed to paragraph 5-2.7). If the rectifier does not
have taps, proceed to paragraph 5-2.6; if that test is normal, the rectifier must be
removed from the cabinet for checkout. Refer to specific rectifier manual to
troubleshoot the diodes/selenium plates and the transformer. For general reference,
see paragraph 5-2.7 for the stacks and paragraph 5-2.9 for the transformer.
5-2.6
Fuses. Check all fuses and measure AC voltage input to the rectifier. With
power OFF, remove all fuses at the rectifier and any fusible disconnect. Measure the
continuity of fuses with a handheld multimeter. Set scale to ohms; measure resistance
of each fuse. Corrosion on fuse end caps or fuse holders will also cause loss of
voltage. Replace any fuse with measurable resistance, or clean and reinstall fuses if
corrosion is found. If a disconnect exists, measure the AC voltage with a handheld
multimeter on the AC volts scale. Measure the voltage on the rectifier side of the
disconnect. If a disconnect does not exist, measure the AC voltage from the circuit
breaker of the rectifier with a handheld multimeter on AC volts scale. For 110/120 volt,
single-phase rectifiers turn power to the rectifier OFF, open cabinet and connect meter
to A3 (output of circuit breaker) and ground (cabinet). Turn power to the rectifier ON
and the rectifier circuit breaker ON; measure voltage from the rectifier circuit breaker.
For 220/240 volt, single-phase rectifiers, use the same procedures, but connect meter
to A4 and (instead of cabinet ground) the output side of the circuit breaker on the
second power lead (not shown on drawing). If voltage is present, proceed to paragraph
5-2.6.1. If voltage is not present, proceed to paragraph 5-2.6.2.
5-2.6.1
Voltage is Present. This indicates either the transformer or the connections
inside the rectifier are faulty (proceed to paragraph 5-2.9).
5-2.6.2
Voltage is Not Present. This indicates loss of AC Power to the rectifier.
Measure the AC voltage to the circuit breaker of the rectifier with a handheld multimeter
on the AC volt scale. For 110/120 volt, single-phase rectifiers turn power to the rectifier
OFF, open cabinet and connect meter to A1 and A4. Turn power to the rectifier ON;
measure voltage to rectifier. For 220/240 volt, single-phase rectifiers, use the same
procedures, but connect meter to A4 and input side of the circuit breaker (A1) on the
second power lead (not shown on drawing). If voltage is not present, proceed to
paragraph 5-2.10; or if voltage is present, replace circuit breaker or fuse.
5-8
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