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13

Instruction Book    

IB182923EN   September 2018   www.eaton.com

AMH-4.76-VR

+

VR-Series

 Replacement Circuit Breaker

m

 DANGER

FAILURE TO REPLACE THE VACUUM INTERRUPTER ASSEMBLY WHEN 

INDICATED BY THE CONTACT EROSION INDICATOR COULD CAUSE THE 

CIRCUIT BREAKER TO FAIL, LEADING TO DEATH, SEVERE PERSONAL 

INJURY, EQUIPMENT DAMAGE AND/OR IMPROPER OPERATION.

4.1.3   CONTACT WIPE AND STROKE

The circuit breaker mechanism provides a fixed amount of motion 

to the operating rods connected to the moving stem of the vacuum 

interrupter. The first portion of the motion, the stroke, is used to 

close the vacuum interrupter contacts; the remainder of that motion, 

the wipe, is used to further compress the pre-loaded wipe spring. 

Contact stroke and wipe are related; contact wipe is the indication 

of the force holding the vacuum interrupter contacts closed as well 

as the energy available to hammer the contacts open with sufficient 

speed for interruption. Stroke is the gap between the stationary and 

moving contact of the vacuum interrupter when the circuit breaker 

is open. As the stroke increases due to contact erosion inside the 

vacuum interrupter, the wipe decreases. Although these changes 

are taking place as operations accumulate on the vacuum interrupter, 

field adjustment of the wipe or stroke are not necessary during the 

lifetime of the vacuum interrupter. 

m

 WARNING

THERE IS NO PROVISION FOR IN-SERVICE ADJUSTMENTS OF CONTACT 

WIPE AND STROKE. ALL SUCH ADJUSTMENTS ARE FACTORY SET AND 

SHOULD NOT BE ATTEMPTED IN THE FIELD.

4.2   PHASE BARRIERS

Phase barriers are sheets of insulation located between the 

interrupter pole assemblies and on the sides of the breaker frame. 

The phase barriers are designed to isolate energized conductor 

components in each phase from the adjacent phase and ground.

m

 WARNING

ALL PHASE BARRIERS MUST BE IN PLACE BEFORE PLACING THE 

CIRCUIT BREAKER INTO SERVICE. FAILURE TO HAVE THEM IN POSITION 

CAN CAUSE DEATH, SERIOUS PERSONNEL INJURY AND/OR PROPERTY 

DAMAGE.

4.3   BUSHINGS AND DISCONNECTING CONTACT 

ASSEMBLIES

The line and load bushing assemblies, which are the primary 

circuit terminals of the circuit breaker, consist of six silver plated 

conductors. Solid stab type primary disconnecting contacts at 

the ends of the conductors provide means for connecting and 

disconnecting the circuit breaker to the bus terminals in the 

switchgear compartment.

4.4   STORED ENERGY MECHANISM

The spring-type stored energy operating mechanism is mounted 

on the circuit breaker frame and in the front of the circuit breaker. 

Manual closing and opening controls are at the front cover (Figure 

Set 3.3). They are accessible while the circuit breaker is in any of its 

basic installation positions. (See Section 5 in this manual)
The mechanism stores the closing energy by charging the closing 

springs. Spring charging is automatically accomplished when control 

power is applied to the circuit breaker secondary disconnect contact. 

When released, the stored energy closes the circuit breaker, charges 

the wipe and resets the opening springs. The mechanism may rest 

in any one of the four positions shown in Figure 4.6 as follows:
a. Circuit breaker open, closing springs discharged.
b. Circuit breaker open, closing springs charged.
c. Circuit breaker closed, closing springs discharged.
d. Circuit breaker closed, closing springs charged.

m

 DANGER

KEEP HANDS AND FINGERS AWAY FROM CIRCUIT BREAKER’S INTERNAL 

PARTS WHILE THE CIRCUIT BREAKER CONTACTS ARE CLOSED OR THE 

CLOSING SPRINGS ARE CHARGED. THE CIRCUIT BREAKER CONTACTS 

MAY OPEN OR THE CLOSING SPRINGS DISCHARGE CAUSING CRUSHING 

INJURY. DISCHARGE THE SPRINGS AND OPEN THE CIRCUIT BREAKER 

BEFORE PERFORMING ANY MAINTENANCE, INSPECTION OR REPAIR ON 

THE CIRCUIT BREAKER.

THE DESIGN OF THIS CIRCUIT BREAKER ALLOWS MECHANICAL CLOSING 

AND TRIPPING OF THE CIRCUIT BREAKER WHILE IT IS IN THE ‘CONNECT’ 

POSITION. HOWEVER, THE CIRCUIT BREAKER SHOULD BE CLOSED 

MECHANICALLY ONLY IF THERE IS POSITIVE VERIFICATION THAT LOAD 

SIDE CONDITIONS PERMIT. IT IS RECOMMENDED THAT CLOSING THE 

CIRCUIT BREAKER IN THE ‘CONNECT’ POSITION ALWAYS BE DONE WITH 

THE CUBICLE DOOR CLOSED. FAILURE TO FOLLOW THESE DIRECTIONS 

MAY CAUSE DEATH, SEVERE PERSONAL INJURY, EQUIPMENT DAMAGE 

AND/OR IMPROPER OPERATION.

ELECTRICAL TRIPPING CAN BE VERIFIED WHEN THE CIRCUIT BREAKER IS 

IN THE ‘DISCONNECT / TEST’ POSITION.

4.4.1   CLOSING SPRING CHARGING

Figure 4.5 shows schematic section views of the spring charging 

parts of the stored energy mechanism.
The major component of the mechanism is a cam shaft assembly 

which consists of a shaft to which are attached two closing spring 

cranks (one on each end), the closing cam, drive plate, and a free-

wheeling ratchet wheel.
The ratchet wheel (6) is actuated by an oscillating ratchet lever 

(12) and drive pawl (10) driven by the motor eccentric cam. As the 

ratchet wheel rotates, it pushes the drive plates which in turn rotate 

the closing spring cranks and the closing cam on the cam shaft. 

The motor will continue to run until the limit switch “LS” contact 

disconnects the motor.
The closing spring cranks have spring ends connected to them, 

which are in turn coupled to the closing springs. As the cranks 

rotate, the closing springs get charged.
The closing springs are completely charged, when the spring cranks 

go over dead center and the closing stop roller (9) comes against the 

spring release latch (1). The closing springs are now held in the fully 

charged position.
The closing springs may also be charged manually as follows: Insert 

the end of the maintenance tool into the manual charge socket 

opening and charge the closing springs by moving the handle up 

and down the full range of motion. When charging is complete the 

ratchet will no longer advance and the spring charged / discharged 

indicator displays ‘Charged’. (Figure Set 3.3). Any further motion of 

the maintenance tool will not result into advance of charging.

4.4.2   CLOSING OPERATION

Figure 4.6 shows the positions of the closing cam and tripping 

linkage for four different operational states. In Figure 4.6.a the 

circuit breaker is open and the closing springs are not charged. In 

this state, the trip latch (8) is disengaged from the trip “D” shaft (9) 

(unlatched). After the closing springs become charged, the trip latch 

snaps into the fully reset or latched position (Figure 4.6.b)

The mechanism is a mechanically “trip-free” design. Trip-free is 

defined in Section 4.3.4 (Trip-Free Operation).
In normal operation the closing spring is charged by the spring 

charging motor, and the circuit breaker is closed electrically by the 

switchgear control circuit signal to energize the spring release coil. 

Tripping is caused by energizing the trip coil through the control 

circuit.
For maintenance inspection purposes the closing springs can be 

charged manually by using the maintenance tool and the circuit 

breaker can be closed and tripped by pushing the “Push to Close” 

and “Push to Open” operators on the front cover.

Summary of Contents for VR+ Series

Page 1: ...September 2018 Instruction Book IB182923EN AMH 4 76 VR VR Series Replacement Circuit Breaker Effective AMH 4 76 VR 1200A Shown...

Page 2: ...f further information is required an Eaton sales office should be consulted Sale of the product shown in this literature is subject to the terms and conditions outlined in appropriate Eaton selling po...

Page 3: ...NTERLOCKS 14 4 7 1 ANTI CLOSE INTERLOCK 14 4 7 2 RACKING SYSTEM TRIP AND SPRING RELEASE INTERLOCKS 14 4 7 3 ACTIVE INTERLOCK 15 4 7 4 SHUTTER INTERLOCK 15 4 8 MISCELLANEOUS ITEMS 15 4 8 1 OPERATIONS C...

Page 4: ...important that this installation and maintenance instruction booklet be read and followed closely to achieve optimum performance and a long useful circuit breaker life in its application 1 1 VISUAL IN...

Page 5: ...ted Voltage Factor Rated Withstand ANSI Test Voltage Rated Short Circuit Maximum Sym Interrupting Capability Closing and Latching Momentary Capabilities kV MVA Amps K Low Freq kV RMS Impulse kV Peak I...

Page 6: ...R VR Series Replacement Circuit Breaker E H I G F J H D B C C A Table 2 AMH 4 76 VR Dimensions Breaker Type Existing Breaker Rated Continuous Current at 60 Hz Amps A B C D E F G H I J AMH 4 76 VR 250...

Page 7: ...injury and or property damage Do not work on a breaker with the secondary test coupler engaged Failure to disconnect the test coupler could result in an electrical shock leading to death personnel inj...

Page 8: ...ker Style 94C9506G01 Racking Handle The racking handle is used to drive the racking mechanism which moves the circuit breaker into and out of the cell The original OEM racking handle will interface wi...

Page 9: ...d indicator Push the manual trip button The breaker will trip as shown by the breaker contacts open green indicator After completing this initial check leave the closing springs discharged and breaker...

Page 10: ...ernal View of AMH 4 76 VR AMH 4 76 VR 250 1200A Shown Front External View 1 Manual Charging Socket 5 Guide Bar 9 Push to Open Button 2 Push To Close Button 6 Breaker Contacts Indicator 10 MOC Actuator...

Page 11: ...ment Circuit Breaker Figure 3 4 Rear External View of AMH 4 76 VR AMH 4 76 VR 250 1200A Shown Rear External View 1 Shutter Actuator 4 SURE CLOSE Spring 7 Secondary Disconnect 2 Primary Disconnect 5 Gu...

Page 12: ...R ASSEMBLY Each vacuum interrupter assembly also referred to as pole unit is assembled at the factory as a unit to assure correct dimensional relationships between working components Three interrupter...

Page 13: ...ND FINGERS AWAY FROM CIRCUIT BREAKER S INTERNAL PARTS WHILE THE CIRCUIT BREAKER CONTACTS ARE CLOSED OR THE CLOSING SPRINGS ARE CHARGED THE CIRCUIT BREAKER CONTACTS MAY OPEN OR THE CLOSING SPRINGS DISC...

Page 14: ...ct opens the SR circuit so that even though the circuit breaker would subsequently open it could not be reclosed before CS C was released and remade This is the anti pump function 4 5 1 TIMING The ope...

Page 15: ...ted by the circuit breaker shutter actuator that opens the shutter as the circuit breaker is racked into the circuit breaker compartment and closes the shutter as the circuit breaker is racked out of...

Page 16: ...pt between Test and Connect positions OPERATION C and NO C and NC C and NO C and NO C and NC C and NO Brown Switch Black Switch Black Switch Brown Switch SWITCH TERMINAL LS1 bb LS2 aa LS2 bb LC PS1 PS...

Page 17: ...ront Faceplate Removed VR Series Circuit Breaker Element Mechanism 1 LH Closing Spring 5 Spring Release Assembly 9 Manual Charge Socket 2 Motor Cutoff Switch 6 Shunt Trip Assembly 10 Ratchet wheel 3 L...

Page 18: ...nkage 1 Spring Release Close Latch 6 Ratchet Wheel 11 Anti Close Interlock 2 Pole Shaft 7 Spring Crank 12 Motor Ratchet Lever 3 Closing Spring Fixed End 8 Cam Shaft 13 Spring Release Close Clapper 4 C...

Page 19: ...Closing Spring Discharged 4 9 c Breaker Closed and Closing Spring Discharged 4 9 b Breaker Open and Closing Spring Charged 4 9 d Breaker Closed and Closing Spring Charged Charging Schematic 1 Main Li...

Page 20: ...does not fully open or close it is time to maintain the MOC in the cell Maintenance usually means cleaning and lubricating the MOC mechanism If the MOC has seen a large number of cycles however worn c...

Page 21: ...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 m NOTICE IF THE...

Page 22: ...s 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...

Page 23: ...uit breaker can be operated either electrically or mechanically Remove rotary racking handle before performing any testing b To further remove the circuit breaker to the disconnect position continue t...

Page 24: ...lace Insulation Integrity Main circuit to ground Withstand 15kV 60Hz for 1 Minute 5kV Rating 27kV 60Hz for 1 Minute 8 25kV and 15kV Ratings Hi pot Tester Clean and retest or replace Control circuit to...

Page 25: ...t is recommended that the equipment be capable of delivering 25 milliamperes for one minute The current delivery capability of 25 mA ac applies when all three vacuum interrupters are tested in paralle...

Page 26: ...from Ohm s Law and is expressed in micro ohms Repeat for the remaining two poles The resistance should not exceed the factory test levels more than 200 as stated in IEEE C37 09 Factory test levels ar...

Page 27: ...e Tool Mounting Testing Locations by Circuit Breaker Type CIRCUIT BREAKER DESIGNATION APPROXIMATE MECHANISM CHASSIS WIDTH INCH LOWER MOUNTING HOLE LOWER MOUNTING HOLE MARKER PLACEMENT HOLE AM4 16 VR 1...

Page 28: ...on a sheet of paper that can be kept as a record of the test Record the date of the test person conducting the test circuit breaker serial number and the operations counter on the tape or paper Figur...

Page 29: ...Marker CloSure Tool TM 15O 15O Figure 6 13 Determining the Distance Traveled Figure 6 14 Illustrative Testing Tape Sample Figure 6 12 Evaluate the CloSure Performance Date of Breaker Operations CloSu...

Page 30: ...lement requires maintenance only once every ten years or ten thousand operations which ever comes first After a ten year service interval or when ten thousand operations have been reached contact your...

Page 31: ...or burned Motor Cut Off Contacts open or burned Trip Coil Assembly Clapper fails to reset Closing sound but no close Pole Shaft Not open fully Trip Latch Reset Spring Damaged or missing Trip Bar D Sha...

Page 32: ...SWITCH Breaker Auxiliary Switch 94C9525G13 5 BREAKER POSITION SWITCH Breaker Position Switch PS1 94C9525H06 6 BREAKER POSITION SWITCH Breaker Position Switch PS2 94C9525H07 7 LATCH CHECK SWITCH Latch...

Page 33: ...33 Instruction Book IB182923EN September 2018 www eaton com AMH 4 76 VR VR Series Replacement Circuit Breaker...

Page 34: ...vard Cleveland OH 44122 United States Eaton com 2018 Eaton All Rights Reserved Printed in USA Publication No IB182923EN September 2018 Eaton is a registered trademark All trademarks are property of th...

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