The electrical controls of the type 38-3AH3
vacuum circuit breaker should be checked
during inspection to verify absence of any
mechanical damage, and proper operation
of the automatic-spring charging and close
and trip circuits.
Unless otherwise noted, all of these tests
are performed without any control power
applied to the circuit breaker.
Wiring and terminals check
1. Physically check all of the circuit-
breaker wiring for evidence of
abrasion, cuts, burning or mechanical
2. Check all terminals to be certain they
are solidly attached to their respective
In addition to checking the terminals of the
secondary disconnect, the secondary
contact fingers need to be free to move
without binding. Depress each finger,
confirm presence of spring force (contact
pressure) and verify freedom-of-motion.
Automatic spring-charging check
(control power required)
Repeat the automatic spring-charging
check described in "Installation checks and
initial functional tests" (refer to pages
Hazardous voltage and high-speed moving parts.
Will cause death, serious injury and property damage.
Read instruction manuals, observe safety instructions and use
Primary tasks of this check are:
1. The circuit breaker is energized with
control power for this check.
2. De-energize the source of control
3. Install the circuit-breaker end of the
split-plug jumper over the secondary
disconnect of the circuit breaker. The
split-plug jumper has one male and
one female connector and cannot be
installed incorrectly (refer to Figure 5:
Split-plug jumper connected to circuit
breaker on page 13).
4. Install the switchgear end of the split-
plug jumper over the secondary-
disconnect block inside the switchgear
(refer to Figure 6: Split-plug jumper
connected to switchgear on page 13).
5. Energize the control-power source.
6. When control power is connected to
the circuit breaker, the closing springs
should automatically charge. Visually
verify the closing springs are CHARGED.
Note: A temporary source of control power
and test leads may be required if the
control-power source has not been
connected to the switchgear. When control
power is connected to the type 38-3AH3
vacuum circuit breaker, the closing springs
should automatically charge.