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26

Instruction Book    

IB182923EN   September 2018   www.eaton.com

AMH-4.76-VR

+

VR-Series

 Replacement Circuit Breaker

6.5   INSULATION

In VR-Series

+

 circuit breakers, insulation maintenance primarily 

consists of keeping all insulating surfaces clean. This can be done 

by wiping off all insulating surfaces with a dry lint free cloth or 

dry paper towel. In case there is any tightly adhering dirt that will 

not come off by wiping, it can be removed with a mild solvent or 

distilled water. But be sure that the surfaces are dry before placing 

the circuit breaker in service. If a solvent is required to cut dirt, use 

Isopropyl Alcohol or commercial equivalent. Secondary control wiring 

requires inspection for tightness of all connections and damage to 

insulation.

6.6   INSULATION INTEGRITY CHECK

PRIMARY CIRCUIT:

The integrity of primary insulation may be checked by the ac high 

potential test. The test voltage depends upon the maximum rated 

voltage of the circuit breaker. For the circuit breakers rated 4.76 kV 

the test voltage is 15 kV RMS 60Hz, 27kV RMS 60 Hz for circuit 

breakers rated 8.25 kV and 15 kV.  Conduct the test as follows:
Close the circuit breaker. Connect the high potential lead of the 

test machine to one of the poles of the circuit breaker. Connect 

the remaining poles and circuit breaker frame to ground. Start 

the machine with output potential at zero and increase to the 

test voltage. Maintain the test voltage for one minute. Repeat for 

the remaining poles. Successful withstand indicates satisfactory 

insulation strength of the primary circuit.
Open the circuit breaker. Connect the high potential lead of the 

test machine to one of the terminals of the circuit breaker. Connect 

the remaining terminals and circuit breaker frame to ground. Start 

the machine with output potential at zero and increase to the 

test voltage. Maintain the test voltage for one minute. Repeat for 

the remaining poles. Successful withstand indicates satisfactory 

insulation strength of the primary circuit.

SECONDARY CIRCUIT:

Isolate the motor by disconnecting the two motor leads from the 

terminal block. Connect all points of the secondary disconnect 

contact pins with a shooting wire. Connect this wire to the high 

potential lead of the test machine. Ground the circuit breaker 

frame. Starting with zero, increase the voltage to 1125 RMS, 60 Hz. 

Maintain the voltage for one minute. Successful withstand indicates 

satisfactory insulation strength of the secondary control circuit. 

Remove the shooting wire and reconnect the motor leads.

6.7   PRIMARY CIRCUIT RESISTANCE CHECK

The main contacts of the VR-Series

+

 circuit breaker are inside 

the vacuum chamber where they remain clean and require no 

maintenance at any time. 
The dc electrical resistance of the primary circuit may be calculated 

by measuring the voltage drop across the circuit. This test should 

be performed with a low voltage, direct current (dc) power supply 

capable of delivering no less 100A dc. 

• 

To check the primary circuit resistance:

• 

Remove the circuit breaker from the circuit breaker 

compartment

• 

Close the circuit breaker

• 

Pass at least 100A dc from terminal to terminal of each pole 

unit in the closed position 

• 

Measure the voltage drop across the terminals. 

The resistance can be calculated 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 are recorded 

on the circuit breaker test form, which is included with the circuit 

breaker. If measurements exceed 200%, contact the manufacturer.

Resistance conversion for Temperature

R

conversion 

= R

Factory

(1 + (T

Field

 - T

Factory

)

r

)

R

conversion 

= Resistance correction for temperature based from the 

factory resistance measurement.

R

Factory 

= Resistance measurement from the factory.

T

Field 

= Temperature measurement in the field.

T

Factory 

= Temperature measurement from the factory.

r

 = Copper resistivity temperature coefficient.

r

 = 0.0039 Copper Resistivity Temperature Coefficient / Deg C

r

 = 0.002167 Copper Resistivity Temperature Coefficient / Deg F

6.8   VR-SERIES

+

 

CIRCUIT BREAKER ELEMENT MECHANISM 

CHECK

Make a careful visual inspection of the mechanism for any loose 

parts such as bolts, nuts, pins, rings, etc. Check for excessive wear 

or damage to the circuit breaker components. Operate the circuit 

breaker several times manually and electrically. Check the closing 

and opening times to verify that they are in accordance with the 

limits in Table 4.

6.8.1   CLOSURE™ TEST

Introductione:

 The CloSure™ Test is a simple yet extremely effective 

means to determine and monitor the ability of the mechanism to 

close the circuit breaker contacts fully. It provides a quantitative 

measure of the extra energy available in terms of over travel in 

inches to close the circuit breaker contacts to their full extent. It may 

be used periodically to monitor the health of the mechanism.

Gtntral Informatione:

 The CloSure™ Test can be performed on all 

VR-Series

+

 circuit breakers. (Refer to Table 6.2.) If the CloSure™ 

travel obtained is as specified, the mechanism performance is 

satisfactory. If the CloSure™ travel does not conform as shown 

in Figure 6.14, contact Eaton’s Electrical Engineering Services & 

Systems for further information. (See Step 14).

m

 DANGER

DO NOT ATTEMPT TO INSTALL OR PERFORM MAINTENANCE OR TESTS ON 

THE EQUIPMENT WHILE IT IS ENERGIZED. NEVER PUT YOUR HANDS NEAR 

THE MECHANISM WHEN THE CIRCUIT BREAKER IS IN THE CHARGED OR 

CLOSED POSITION. DEATH OR SEVERE PERSONAL INJURY CAN RESULT 

FROM CONTACT WITH ENERGIZED EQUIPMENT. ALWAYS VERIFY THAT 

NO VOLTAGE IS PRESENT BEFORE PROCEEDING WITH THE TASK, AND 

ALWAYS FOLLOW GENERALLY ACCEPTED SAFETY PROCEDURES.

Saftty Prtcautionse:

 Read and understand these instructions before 

attempting any maintenance, repair or testing on the circuit breaker. 

The user is cautioned to observe all recommendations, warnings and 

cautions relating to the safety of personnel and equipment. 

otte:

N

Htaring prottction is rtcommtndtd as tht circuit brtaktr is 

optntd and clostd.

The recommendations and information contained herein are based 

on Eaton experience and judgment, but should not be considered to 

be all-inclusive or covering every application or circumstance which 

may arise. If further information is required, you should consult 

Eaton’s Electrical Services & Systems.

Ttsting Proctdurtse:

 Assuming that the circuit breaker is safely 

removed from the circuit breaker compartment enclosure and 

positioned in an area outside the arc fault boundary, follow this 

procedure to perform the CloSure™ test. For further instructions on 

removal of the circuit breaker from the circuit breaker compartment, 

refer to the appropriate section of this manual.

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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