28
Instruction Book
IB182012EN March 2017 www.eaton.com
50DH-VR-50AXU / 50XU / 75U / 75ARU - 600 / 1200A
Replacement Circuit Breaker
SECTION 6: INSPECTION & MAINTENANCE
DANGER
DO NOT WORK ON A CIRCUIT BREAKER IN THE “CONNECTED” POSITION.
DO NOT WORK ON A CIRCUIT BREAKER WITH SECONDARY
DISCONNECTS ENGAGED.
DO NOT WORK ON A CIRCUIT BREAKER WITH SPRINGS CHARGED OR
CONTACTS CLOSED.
DO NOT DEFEAT ANY SAFETY INTERLOCKS.
DO NOT LEAVE MAINTENANCE TOOL IN THE SOCKET AFTER CHARGING
THE CLOSING SPRINGS.
DANGER
STAND AT LEAST ONE METER AWAY FROM THE CIRCUIT BREAKER WHEN
TESTING FOR VACUUM INTEGRITY.
FAILURE TO FOLLOW ANY OF THESE INSTRUCTIONS MAY CAUSE DEATH,
SERIOUS BODILY INJURY, OR PROPERTY DAMAGE. SEE SECTION 2 - SAFE
PRACTICES FOR MORE INFORMATION.
6.1 INSPECTION FREQUENCY
Inspect the circuit breaker once a year when operating in a clean,
non corrosive environment. For a dusty and corrosive environment,
inspection should be performed twice a year. Additionally, it is
recommended to inspect the circuit breaker every time it interrupts
fault current.
ote:
N
Refer to the table below for maintenance and inspection check points.
6.2 INSPECTION AND MAINTENANCE PROCEDURES
NO. / SECTION
INSPECTION ITEM
CRITERIA
INSPECTION METHOD
CORRECTIVE ACTION IF NECESSARY
1. Insulation
Stand Off Insulators, Operating Rods,
Tie-Bars and Barriers
No Dirt
Visual Check
Clean With Lint-Free Cloth
No Cracking
Visual Check
Replace Cracked Unit
Vacuum Integrity
Between Main Circuit With
Terminals Ungrounded
Withstand
27k 60Hz For 1 Minute
Hipot Tester
Clean And Retest Or Replace
Insulation Integrity
Main Circuit To Ground
Withstand
15kV, 60Hz For 1 Minute
(5kV Rating)
27kV, 60Hz For 1 Minute
(15kV Ratings)
Hipot Tester
Clean And Retest Or Replace
Control Circuit To Ground
(Charging Motor Disconnected)
Withstand
1125V, 60Hz For 1 Minute
Hipot Tester
Clean And Retest Or Replace
2. Power Element
Vacuum Interrupters
Contact Erosion Visibility Of Mark
Visual - Close The Circuit Breaker And
Look For Green Mark On Moving Stem
From The Rear Of The Circuit Breaker
(See Figure 6.1 and 6.2)
If Mark Is Not Visible, Replace Interrupter
Assembly
Contact Wipe Visible
Visual (Figure 6.3 and 6.4)
Replace VI Assembly
Adequate Vacuum
See Section 6.3
Replace Interrupter Assembly
If Vacuum Is Not Adequate
Dirt On Ceramic Body
Visual Check
Clean With Dry Lint-Free Cloth
Primary Disconnects
No Burning Or Damage
Visual Check
Replace If Burned, Damaged Or Eroded
3. Control Circuit Parts
Closing And Tripping Devices
Including Disconnects
Smooth And Correct Operation By
Control Power
Test Closing And Tripping Of The
Circuit Breaker Twice
Replace Any Defective Device-
Identify Per Trouble-Shooting Chart
Wiring
Securely Tied In Proper Place
Visual Check
Repair Or Tie As Necessary
Terminals
Tight
Visual Check
Tighten Or Replace If Necessary
Motor
Smooth And Correct Operation By
Control Power
Test Closing And Tripping Of The
Circuit Breaker Twice
Replace Brushes Or Motor
Tightness Of Hardware
No Loose Or Missing Parts
Visual And Tightening With
Appropriate Tools
Tighten Or Reinstate If Necessary
4. Operating Mechanism Dust Or Foreign Matter
No Dust Or Foreign Matter
Visual Check
Clean As Necessary
Lubrication
Smooth Operation And No
Excessive Wear
Sight And Feel
Lubricate Very Sparingly
With Light Machine Oil
Deformation Or Excessive Wear
No Excessive Deformation Or Wear
Visual And Operational
Remove Cause And Replace Parts
Manual Operation
Smooth Operation
Manual Charging Closing
And Tripping
Correct Per Trouble-Shooting Chart
If Necessary
CloSure
™
Test
> 0.6 Inch Over Travel
CloSure
™
Test 6.8.1
If < 0.6 Contact P.B.C.
At 1-877-276-9379
BOLT SIZE
8 - 32
10 - 32
.25 - 20
.31 - 18
.38 - 16
.50 - 13
TORQUE Lb. In.
24
36
72
144
300
540
