32
Testing the Tripping Actuator
If the device fails to trip the circuit breaker, the trouble may
be in the tripping actuator.
Testing the Actuator on the Circuit
Breaker
1.
Place the selector switch in the “Actuator Test” position.
This energizes the red and black five-way binding posts.
2.
Use the voltmeter lead 18-732-184-503 to connect the
five-way binding posts to the actuator leads on the
circuit breaker. These connect to the static trip terminals
7 and 8 on circuit breakers with STATIC TRIP II or first
generation static trip devices. These leads are con-
nected with “Faston Couplers” when Limitrip devices are
supplied; the red post connects to the red wire on the
actuator (terminal 8), the black post connects to the
black actuator wire (terminal 7). If the static trip is not
disconnected, do not exceed 12 volts DC input while
testing the actuator.
3.
Close the circuit breaker.
4.
Slowly increase the voltage from the internal supply with
the “Power Control” knob. Note the voltage at which the
circuit breaker trips. This should be somewhere be-
tween 4.5 and 10 volts.
5.
Rotate “Power Control” knob counterclockwise to re-
move power.
6.
Failure of the circuit breaker to trip at any voltage even
up to 12 volts may be due to the actuator plunger
binding. This can be checked manually. USE EXTREME
CAUTION WHEN WORKING ON THE CIRCUIT
BREAKER. THE ENERGY STORED IN THE CLOSING
AND/OR OPENING SPRINGS MUST BE RESPECTED.
ALWAYS DISCHARGE ALL SPRINGS BEFORE PLAC-
ING HANDS NEAR THE MECHANISM. See the circuit
breaker instruction book if any problem is evident in the
mechanical portion.
7.
Measure the actuator coil resistance. This measurement
should be made with the static trip disconnected from
the actuator. There are three types of actuators of the
“sealed” type. One has a resistance of 25 to 30 ohms
and should trip between 4.5 and 6 volts maximum. The
second type has a resistance of 30 to 40 ohms and its
tripping voltage should be between 4.5 and 10 volts. The
third type has three coil leads, from red to black has a
resistance of 15 to 20 ohms and trips at 3 to 5 volts. The
resistance from black to blue is 40 to 50 ohm and trips
at 13-20 volts with positive on the blue lead.
Bench Testing Actuators
1.
Set the selector switch to the “Actuator Test” position.
2.
Connect the red actuator lead to the red five-way
binding post and the black actuator lead to the black
five-way binding post.
3.
Manually reset the actuator plunger by pushing the rod
all the way in. Keep the actuator away from any steel
during the test since the steel will change the magnetic
circuit of the device.
4.
Slowly increase the voltage from the internal supply with
the “Power Control” knob. Note the voltage at which the
circuit breaker trips.
5.
Rotate “Power Control” knob counterclockwise to re-
move power.
6.
Check the actuator coil resistance and determine if the
tripping voltage satisfies the applicable maximum value
as stated in step 7 of the preceding section
