21
Instruction Book
IB182923EN September 2018 www.eaton.com
AMH-4.76-VR
+
VR-Series
+
Replacement Circuit Breaker
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WARNING
KEEP HANDS OFF THE TOP EDGE OF THE FRONT BARRIER WHEN PUSHING
A CIRCUIT BREAKER INTO A CELL. FAILURE TO DO SO COULD RESULT IN
BODILY INJURY, IF FINGERS BECOME WEDGED BETWEEN THE CIRCUIT
BREAKER AND THE CELL. USE THE HANDLES PROVIDED ON THE FRONT OF
THE CIRCUIT BREAKER FACEPLATE, OR USE BOTH FULLY OPENED HANDS
FLAT ON THE FRONT OF THE FACEPLATE.
These checks can be performed with the circuit breaker in its
withdrawn or disconnect position and connecting the circuit breaker
to a test cabinet or to the switchgear cell’s secondary receptacle
using the special extension cable designed for this purpose and
described in Section 3.
Perform electrical operations checks. Close and trip the circuit
breaker electrically several times to verify that the operation is
reliable and consistent. Check that the operation of the spring
charging motor is reasonably prompt and that the motor makes no
unusual noise.
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WARNING
DO NOT PERFORM ELECTRICAL OPERATION CHECKS WITH THE CIRCUIT
BREAKER IN THE “CONNECT” POSITION BECAUSE OF THE POSSIBILITY OF
CONNECTING DE-ENERGIZED LOAD CIRCUITS TO THE ELECTRICAL POWER
SOURCE, RESULTING IN DEATH, PERSONNEL INJURY OR EQUIPMENT
compressed spring length (measured in the open position) is
recorded if different than the dimension in this instruction book.
Sttp 11e:
After an adjustment is made, make sure that all nuts are
secured in place, prior to returning to service.
5.3 MANUAL OPERATION CHECK
Manual operational checks must be performed before the circuit
breaker is connected to an energized circuit. Tests must be
performed with the circuit breaker withdrawn from the cell or in the
disconnect position. While the circuit breaker is withdrawn or in the
disconnect position, place the maintenance tool into the manual
charge socket opening and charge the closing springs with about
36 up and down strokes of the handle. When charging is complete,
the closing crank goes over center with an audible “click” and the
springs Charged / Discharged Indicator shows “Charged”. Remove
the maintenance tool.
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NOTICE
IF THE SPRINGS ARE TO BE CHARGED ON A CLOSED CIRCUIT BREAKER,
NO CLICK IS HEARD AT THE END OF CHARGING OPERATION. DISCONTINUE
CHARGING AND REMOVE THE MAINTENANCE TOOL AS SOON AS
“CHARGED” FLAG IS FULLY VISIBLE. CONTINUE ATTEMPTS TO FURTHER
CHARGE MAY RESULT IN DAMAGE TO THE MECHANISM.
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WARNING
ALWAYS REMOVE THE MAINTENANCE TOOL AFTER CHARGING THE
SPRING. FAILURE TO REMOVE THE MAINTENANCE TOOL FROM THE
BREAKER COULD CAUSE INJURY TO PERSONNEL AND/OR EQUIPMENT
DAMAGE IF THE BREAKER WAS TO CLOSE.
Close and trip the circuit breaker by pushing the close lever then the
trip lever (Figure 3.3).
5.4 VACUUM INTERRUPTER INTEGRITY
Using a dry lint-free cloth or a paper towel, clean all the insulating
surfaces of the pole units. Conduct a vacuum interrupter integrity
check as described in Section 6.
5.5 LOW FREQUENCY WITHSTAND TEST (INSULATION
CHECK)
Check breaker primary and secondary insulation per Section 6.
5.6 CONTACT EROSION AND WIPE
Manually charge the closing springs and close the circuit breaker.
Check contact erosion and wipe as described in Section 6.
5.7 PRIMARY CIRCUIT RESISTANCE
Check the primary circuit resistance as described in Section 6. The
resistance should not exceed the values specified. Record the values
obtained for future reference.
5.8 ELECTRICAL OPERATIONS CHECK
After going through the above steps, the circuit breaker is now
ready to be operated electrically. It is preferred that this check be
made with the circuit breaker in the Test position in the breaker
compartment.
Since the Type AMH-4.76-VR+ Circuit Breaker is for use in existing
AMH Metal-Clad Switchgear, installation procedures are similar. If it
is necessary to reference anything in the breaker compartment, refer
to the original instruction books supplied with the assembly.
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WARNING
EXAMINE THE INSIDE OF THE CELL BEFORE INSERTING THE BREAKER
FOR EXCESSIVE DIRT OR ANYTHING THAT MIGHT INTERFERE WITH THE
CIRCUIT BREAKER TRAVEL.
Figurt 5.2. AMH-VR+ in tht Disconntct Position
