iii
Instruction Book
IB182012EN March 2017 www.eaton.com
50DH-VR-50AXU / 50XU / 75U / 75ARU - 600 / 1200A
Replacement Circuit Breaker
Table of Contents
SECTION 1: INTRODUCTION
4
1.1 AVAILABLE 50DH-VR CIRCUIT BREAKERS
4
SECTION 2: SAFE PRACTICES
7
SECTION 3: RECEIVING, HANDLING, AND STORAGE
8
3.1 RECEIVING
8
3.2 HANDLING
8
3.3 STORAGE
9
3.4 APPROXIMATE WEIGHT BY TYPE
9
SECTION 4: DESCRIPTION AND OPERATION
14
4.1 VCP-TR VACUUM CIRCUIT BREAKER ELEMENT
14
4.2.1 CONTACT EROSION INDICATOR
14
4.2.2 CONTACT WIPE AND STROKE
14
4.3 PHASE BARRIERS
14
4.4 BUSHINGS AND DISCONNECTING
CONTACT ASSEMBLIES
14
4.5 STORED ENERGY MECHANISM
15
4.6 ELECTRICAL POSITION
15
4.7 TRIP-FREE OPERATION
15
4.8 ANTI-PUMP FEATURE
15
4.9 LATCH CHECK SWITCH
15
4.10 TIMING
15
4.11 SECONDARY DISCONNECT BLOCK
15
4.12 INTERLOCKS
15
4.12.1 RACKING SYSTEM TRIP AND
CLOSING SPRING RELEASE INTERLOCKS
17
4.13 CELL POSITION DESCRIPTION
17
4.13.1 50DH-VR 50AXU / 75U - FRONT RACKING
17
4.13.2 50DH-VR 50XU / 75ARU - REAR RACKING
18
4.14 MISCELLANEOUS ITEMS
20
4.14.1 GROUNDING CONTACT
20
SECTION 5: INSPECTION & INSTALLATION
21
5.1 EXAMINATION FOR DAMAGE
21
5.1.1 NAMEPLATE VERIFICATION
21
5.2 CELL MODIFICATIONS
21
5.2.1 CELL CLEARANCE MODIFICATIONS
FOR 50-DH-VR-50AXU & 75U (FRONT RACKING)
21
5.2.2 CELL CLEARANCE AND SHUTTER MODIFICATIONS
FOR 50-DH-50XU & 75ARU (REAR RACKING)
25
5.3 INSERTION PROCEDURES
26
5.3.1 50-DH-VR-50 AXU/75U (FRONT RACKING)
26
5.3.2 50-DH-VR-50 XU/75ARU (REAR RACKING)
27
5.4 REMOVAL PROCEDURE
27
5.4.1 50-DH-VR-50 AXU/75U (FRONT RACKING)
27
5.4.2 50-DH-VR-50 XU/75ARU (REAR RACKING)
27
SECTION 6: INSPECTION & MAINTENANCE
28
6.1 INSPECTION FREQUENCY
28
6.2 INSPECTION AND MAINTENANCE PROCEDURES
28
6.3 VACUUM INTERRUPTER INTEGRITY TEST
29
6.4 CONTACT EROSION
29
6.5 CONTACT WIPE
29
6.6 INSULATION
30
6.7 INSULATION INTEGRITY CHECK
30
6.8 PRIMARY CIRCUIT RESISTANCE CHECK
31
6.9 MECHANISM CHECK
31
6.10 LUBRICATION
31
SECTION 7: REPLACEMENT PARTS
33
7.1 GENERAL
33
7.2 ORDERING INSTRUCTIONS
33
