Unipower ARR Series, Руководство по эксплуатации продукта

Страница: 22 / 55

ARR Series Three Phase, Six Pulse SCR Charger Corrective Maintenance
RS-420, Rev. 7 5-4
PROBLEM POSSIBLE CAUSES SOLUTION
F. Low Output Voltage
Adjustable Within 10% of
Rated Voltage
1. Low AC Input Voltage
a. Unit Connected for 240 Volts AC
and Input is 190 Volts AC.
b. Unit is Connected for 480 Volts
AC and Input is Below 430 Volts
AC.
2. One SCR, SCR gate and/or one diode
open (however, not both in the same
leg of the stack).
3. Printed circuit boards defective.
4. Half-wave operation. If oscilloscope
is available, check voltage wave form
at AC inputs to Bridge rectifier; the
wave form should look like:
Input Should be
±
10% of Nameplate
Voltages. Input Voltage Must be
Increased to fall within
±
10% of
Nameplate Voltage.
a. See Instruction 5.4.2.
a. Replace or see 5.4.6.
a. If waveform shows only one break,
check aux. volt. trans. for voltage from
pt. 7 to 5 & 6 to 5. Each should read
45 VAC
±
15%.
b. If waveform is not correct, replace the
18 point printed circuit board.
c. See instruction 5.4.6.
G. Low Output Voltage
(approximately 50%
output and not adjustable)
with NON-Varying output
current that is less than
30% of charger current
rating. 1. Float and/or equalize potentiometers
open.
2. Defective printed circuit boards.
a. See Instruction 5.4.1.
a. Replace or:
1) Check transistors on 9 pt. board for
opens and shorts (see 5.4.6). Replace
if necessary.
2) Check resistor R2 or R12 for open
(see 5.4.6). Replace if necessary.
H. High Output Voltage
(above equalize value and
not adjustable) with high
output current (not
controlled by adjusting
current limit. 1. Diode (s) and/or SCR (s) shorted.
2. Defective printed circuit boards.
3. SCR (s) is turned on after it warms up
without a need for firing pulses.
a. See Instruction 5.4.6.
a. Replace.
a. Replace both SCR’s
(See instruction 5.4.2.)
I. High Output Voltage with
output current that can be
limited or is not greater
than normal load.
1. Defective printed circuit boards. a. Replace or see 5.4.6.