Maintenance and trouble shooting of Circuit breaker

maintenance and trouble shooting circuit breaker

Specific

The following items and tasks should always be referred to in the instruction book.

• breaker maintenance recommended intervals
• recommended intervals of equipment maintenance
• slow closing procedure
• mechanical adjustment 
• lubrication recommendation
• repairs and replacement procedure
• ordering instruction of renewal parts

General

• Be aware of your limitations. learn all you about the equipment operation before you begin to service it.
• set up clean, clear area in which to work.
• completely read each procedure  while looking at the actual parts before beginning thoroughly understand what is to be done and follow  the procedure step by step.
• use a systematic approach.
• do not panic take a calm and methodical approach.
• take a precaution and observe safety procedure before sevicing the breaker and equipment
• protect finished surface from physical damage and corrosion
• use proper tools for each job.
• never disassemble more than is required.
• parts sequence is important keep track part, place bolt and screwe in envelope and lebel them it is also a good practice to re install bolts and screw after removing the part which they held.
• soaking with penetrating oil can often loosen frozen or very tight bolts and screws, avoid heat since it may melt. warp or remove the temper from many parts.
• when assembling component, after all fasteners evenly.

Description

The description to follow are the basic functions of the various devices.

Spring charging motor

The motor is used to charge the breaker closing spring

closing latch monitor switch

This contact is used to prevent charging the closing springs until the closing latch is properly reset. switch contact are held open between disconnect and connect positions when the breaker is inserted or withdrawn from an enclosure.

spring motor limit switch

There are two contacts an this switch both contacts are open when springs are charged.

contacts 1&2 =

This contact remove power from the charging motor when spring are charged

contacts 3&4=

This contacts pick up the 52Y (anti pump relay)

relay when the spring discharge to engage the anti pump feature.

Negative interlock monitor switch

This contact is used to block the charging circuit while the racking crank is engaged.

charge switch.

These contact monitor the closing spring positions contacts are closed when closing springs are fully charge and contacts are parallel to withstand the current surge of the closing.

closing coil.

This device is a solenoid. when electrically release the closing latch to allow closing spring to discharge. closing the breaker. This coil rated as a momentary coil.

52Y ANTI-PUMP RELAY  

                     

The contacts of this relay prevent a controlled discharging of the closing spring, if the closing signal remains complete up to the breaker. If the circuit remains complete, the closing spring would discharge under the wrong conditions, this is called pumping. Therefore the anti-pump relay prevents the spring from doing the following 

A. Re-closing the breaker after the breaker has opened. 

B. Closing the breaker automatically when the closing spring initially charges after the breaker is inserted. 

C.Cycling the closing spring from charged to discharged to charged and so on until the charging motor fails (motor is not rated for continuous duty).

TRIP COIL 

This device is a solenoid that lifts the trip latch thus allowing the breaker to open. This coil is rated as a momentary coil. 

AUXILIARY switch 

The contacts of the auxiliary switch provide an indication in the control circuit of whether the power circuit (main) contacts are either open or closed. They also de-energize the closing coil and the trip coil. 

TROUBLE-SHOOTING GUIDES

Each of the four guides is based upon certain conditions having taken place. 

FAILS TO CHARGE:

means the closing springs will not compress to charged position. 

This condition can happen after the breaker has been placed in the tested or connected position, or after the breaker has been closed electrically or manually.

FAILS TO CLOSE:

means there has been no discharge of the closing springs, 

which is what mechanically closes the main contacts.

means the breaker is closed and will not open.

TRIP-FREE: 

means when the breaker is given an electrical or manual closing command, 

the closing springs discharge but the mechanism (i.e. main contacts) will not latch closed. 

The contacts return to an open position.

Guide 1

Electrical guide

Fail to charge

1)No voltage 

• fuses
• broken wires
• grounded wires

2)Low voltage

• pinched wires
• loose connection 
• corroded connections

3) limit switch

• improper adjustment 
• switch failure 
• loose wires 

4) charging motor.

• terminal box
• connection loose
• motor failure

mechanical guide

1) motor runs but doesn't charge

• check for rotation of gearbox output shaft
• check shear pin at drive shaft junction
• if charging wheel turns check charging pawl
• check for proper reset of closing latch if close spring immediately discharges at end of charging cycle

2)rack mechanism

• breaker not in position properly
• sliding hail is not reset

Guide 2

Electrical guide

fails to close

1)No voltage

• fuses
• broken wires 
• grounded wires

2)low voltage

• pinched wires
• loose connection 
• grounded connection 

3)Limit switches

• improper adjustment 
• switch failure 
• loose connection

4)auxiliary switch

• loose wires 
• switch failure 
• failure of operating linkage 

5)anti pump relay

• loose wires
• NO contacts bad
• improper dropout 

Mechanical guide

1)trip latch is not resetting

2)check to see if breaker is charge.

3)check  freenes of closing shaft

4)armature linkage

Guide 3

trip free

electrical guide

1)maintained voltage on trip circuits 

2)not resetting

• broken reset spring
• shaft binding
• linkage binding
• trip latch
• negative interlock not properly adjusted 

mechanical guide

toggle link not making toggle position due to bearing.