HindlePower AT30 SERIES Operating And Service Instructions page 61

PROBABLE
SYMPTOM
CAUSE
AC INPUT 1. AC power
FAILURE failure
indicator is on
2. Upstream
feed
breaker/fuse is
tripped
3. Defective
wiring
4. Defective
Main Control PC
Board (A1)
POS GND or 1. Ground fault
NEG GND on external dc
indicator is on bus
2. DC circuit
breaker is open
and POS GND
indicator is on
3. Alarm needs
calibration
4. Defective
wiring
5. Defective
Main Control PC
Board (A1)
6. Paralleled
AT10.1(s) are
shut down
Summary 1. Defective
alarm relay is Main Control PC
in alarm Board (A1)
mode, but no
front panel
alarm indicator
is on
RECOMMENDED ACTION
1. If the ac input power fails, the front panel AC ON indicator goes
out, and the AC INPUT FAILURE indicator goes on.
2. Be sure the front panel ac circuit breaker (CB1) is closed.
Measure the ac voltage at the AT30 input terminals (TB1-L1, TB1-
L2 and TB1-L3). If it is zero, check the upstream distribution
breakers and fuses.
3. Measure ac voltage at the transformer primary taps (T1-H1, T1-
H2 & T1-H3). It should be the same as the ac supply voltage.
4. Turn off both front panel breakers. If the AT30 does not have
breakers (fuses instead), lock out ac and dc power to the AT30
externally. Wait one minute. Return dc power to the AT30 first,
followed by ac power. If the AC ON and AC INPUT FAILURE
indicators are both still on, replace the Main Control PC Board
(A1).
1. Shut down and disconnect the AT30 from the battery and dc
bus. Check the battery and dc bus for a ground fault. See
Application Note (JD5032-00) for assistance.
2. If the AT30 has been placed into "standby" by opening the dc
breaker (CB2), the ground detection circuit supplies an erroneous
alarm. This is considered an abnormal condition for the AT30,
and is not recommended. Close the dc breaker and the alarm
should end. To place the AT30 in "standby", open both front
panel circuit breakers (CB1/CB2).
3. Calibrate the AT30 ground detection sensitivity. See Section
2.3.4.
4. Turn off both front panel breakers. If the AT30 does not have
breakers (fuses instead), lock out ac and dc power to the AT30
externally. Wait one minute. Return dc power to the AT30 first,
followed by ac power. Measure the voltage from TB1(+) to
chassis, and from TB1(-) to chassis. The voltage readings should
be equal, each approximately half of the total output voltage. If
there is more than a 10% imbalance, turn the AT30 off and
inspect all wiring from TB1 to the dc circuit breaker (CB2), and the
rectifier bridge to the dc filter inductor (L1). Look for evidence of
insulation damage, insufficient spacing between terminals and
chassis, or wires run too close to metal edges.
5. Turn off both front panel breakers. If the AT30 does not have
breakers (fuses instead), lock out ac and dc power to the AT30
externally. Wait one minute. Return dc power to the AT30 first,
followed by ac power. If you are sure there is no ground fault on
the external bus or within the AT30, but the POS GND or NEG
GND indicator is still on, replace the Main Control PC Board (A1).
6. Restart all other AT30s connected in parallel with unit that is
experiencing ground fault. Otherwise, disconnect and lock out
from the dc bus all shut down AT30s.
1. Turn off both front panel breakers. If the AT30 does not have
breakers (fuses instead), lock out ac and dc power to the AT30
externally. Wait one minute. Return dc power to the AT30 first,
followed by ac power. If the relay remains in alarm mode, check
the Low Level Detect indicator on Main Control PC Board (A1).
See Section 2.3.8. If no other alarm is on, replace the Main
Control PC Board (A1).
SERVICING THE AT30
57