22
Instruction Book
IB182923EN September 2018 www.eaton.com
AMH-4.76-VR
+
VR-Series
+
Replacement Circuit Breaker
5.9 DESCRIPTION OF OPERATIONAL POSITIONS
This section of the instructional manual covers the AMH line of
Eaton vacuum replacement breakers. The AMH-4.76-VR+ has four
basic operational positions:
(1) Circuit breaker withdrawn from the cell.
(2) Circuit breaker in the cell in the disconnect position. (Figure
5.2)
(3) Circuit breaker in the test position. (Figure 5.4)
(4) Circuit breaker in the connect position. (Figure 5.6)
5.10 INSERTION PROCEDURE
m
WARNING
ARC FLASH INCIDENCES WITH MV SWITCHGEAR CAN OCCUR DURING THE
PROCESS OF INSERTING AND REMOVING POWER CIRCUIT BREAKERS IN
SWITCHGEAR CUBICLES. IT IS STRONGLY RECOMMENDED THAT PROPER
PPE (PERSONAL PROTECTIVE EQUIPMENT) BE WORN BY PERSONNEL
WHO RACK BREAKERS USING THE MANUAL LEVERING HANDLE OR
THE ROTARY RACKING HANDLE. EATON CORPORATION PROVIDES A
UNIVERSAL REMOTE POWER RACKING SYSTEM (RPR-2) WHICH IS
COMPATIBLE WITH THE INTERNAL ROTARY RACKING BREAKERS. THIS
SYSTEM MAY ALLOW PERSONNEL TO WEAR A LOWER LEVEL OF PPE
DURING THE INSERTION OR REMOVAL PROCESS AS LONG AS RACKING
CAN BE PERFORMED FROM OUTSIDE THE FLASH PROTECTION BOUNDARY.
a. Place the circuit breaker in the withdrawn position; verify
the breaker position indicator indicates the breaker is in the
“withdrawn” position.
b. From the withdrawn position, align the guide bar of the circuit
breaker with the guide rails of the cell. (Figure 5.2)
c. Check that the closing spring status indicator reads
“DISCHARGED” and that the main contact status indicator reads
“OPEN”.
d. Push the circuit breaker into the cell until the mechanical stop is
reached, this will be indicated by an audible click. At this point the
side plunger has fallen into the front slot of the guide rail. In this
position the breaker cannot be operated. Verify the circuit breaker
position indicator reads “disconnect”.
e. To further advance the circuit breaker into the cell, step on foot
pedal, and open racking access shutter. (Figure 5.3) When racking
nut is exposed, insert rotary racking handle and turn clockwise.
The breaker will travel approximately 1.5 inches to reach the test
position. (Figure 5.5) The circuit breaker may be stopped in the
test position, as indicated by the circuit breaker and cell position
decals, if electrical or mechanical testing is to be performed.
Remove rotary racking handle before performing any testing.
Figurt 5.3. Advancing tht AMH-VR Into tht Ctll
Figurt 5.5. Racking tht AMH-VR+ Into tht Ctll
Figurt 5.4. AMH-VR+ in tht Ttst Position
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NOTICE
ONCE THE SECONDARY DISCONNECT BLOCK IS ENGAGED IN THE “TEST”
POSITION, IT WILL REMAIN CONNECTED THROUGHOUT FURTHER INWARD
MOVEMENT AS THE CIRCUIT BREAKER ADVANCES FROM THE “TEST” TO
THE “CONNECT” POSITION.
THE SPRING CHARGING MOTOR WILL BEGIN TO RUN, IF THE MOTOR CUT-
OFF SWITCH IS IN THE “ON” POSITION (FIGURE 3.4), AND CHARGE THE
CLOSING SPRINGS AS THE SECONDARY CONNECTION IS MADE AS LONG
AS CONTROL POWER IS AVAILABLE.
f. From the test position, the circuit breaker can be advanced to
the connect position by reinserting the rotary racking handle and
stepping on the interlock pedal. Rotate racking handle clockwise
until the connect position is reached and the handle can no longer
be turned. This can be verified by the circuit breaker position
indicator. (Figure 5.6)
