Manual

14
MAXIMUM OUTPUT CURRENT
NEVER EXCEED THE MAXIMUM OUTPUT CURRENT
RATING OF THE UNIT (Table 1). Excessive output current
can damage the variable auto-transformer.
Keep output current as low as possible; power only one piece
of equipment at a time. Use the ISOLATED OUTPUT only for
the equipment under test – not for the test equipment.
It is very important to observe the maximum current derating
(Table 1) above 130 volts, and to allow sufficient cooling time
when operating Model 1655A in the intermittent duty region.
Even at low voltages, the maximum output current should
never exceed 4 amps for Model 1655A or 2 amps for Model
1653A. Higher current may damage the variable auto-
transformer where the brush contacts the winding. A 3.15A
circuit breaker limits maximum input current to Model 1655A,
while a 3A fuse is used for Model 1653A. Additionally, output
fuses limit the output of the 1655A to 4 amps and the 1653A to 3
amps at low voltages that would not open the input protective
device. Never bypass the circuit breaker or fuses, or replace fuses
with a higher value.
Remove the overload to reset the circuit breaker or replace a
fuse. Turn off the unit when connecting or disconnecting
equipment from the ISOLATED OUTPUT receptacle(s).
For Model 1655A, the red portion of the 0-4A scale of the
meter indicates the caution zone (over 3A). This is a reminder
that only intermittent duty operation is permitted.
For Model 1635A, the output current should not exceed 2 amps
for continuous duty or intermittent duty operation. The full scale
meter indication of 2A is a reminder that this is the maximum
permissible output current.
CAUTION
Precautions
OPERATING INSTRUCTIONS
Table 1. Maximum Output Current Derating.