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8

Trip Screw Adjustment

With the breaker CLOSED, the trip screw [3] must
have zero clearance with the breaker trip paddle. If
adjustment is necessary, OPEN the breaker, make the
adjustment, then CLOSE the breaker to check the
adjustment. Be sure to retighten the adjusting nut.

WARNING

: Be extremely careful when working on a

CLOSED breaker. 

Do not

 reach your hands into the

mechanism while adjusting the flux shifter.

Microswitch Linkage

The following procedure is illustrated in Figures 4, 6,
7, and 8.

1.

Loosen the two top adjusting nuts on the

microswitch link connecting rod [10], as shown in

Figures 6 and 8. Do not attempt to loosen the two

lower nuts, as they have been secured at the

factory with Loctite

®

. Place a 

1 4

" flat washer

over the supplied 

1

4-20 bolt. Insert the bolt in

sequence through the hole in the microswitch

link [11] and the breaker reset link [12]. Place

another flat washer over the bolt, then slide the

bolt through the slot in the flux shifter reset arm

[1]. Place a flat washer and the self-locking nut on

the bolt. 

Do not

 overtighten the nut, as the bolt

must be free to rotate within the connecting links.

2.

With the breaker in the OPEN (reset) position,

push the lower link [7] down until the mounting

pin is at the top of the slot. Tighten the two

adjusting nuts on the connecting rod [10] to

secure the microswitch link.

3.

If required, loosen the two adjusting nuts on the

microswitch plunger [9], located on the

stationary bracket. Adjust the linkage so that the

microswitch position follows the breaker contact

position (microswitch is closed when the breaker

is CLOSED). Retighten the adjusting nuts.

Flux Shifter Test

The operation of the flux shifter may be tested by
closing the breaker, then applying 9 Vdc to the flux
shifter leads (red is positive). The breaker should trip
and reset. If necessary, repeat the adjustments in the
previous procedures.

Figure 6. Flux shifter assembly installed, as viewed from the

bottom of the breaker.

Figure 7. Flux shifter assembly installed, as viewed from the right

front of the breaker (LA-800 shown). .

Mounting

Stud

Breaker

Reset

Link

Flux Shifter

Reset Link

Microswitch

Link

Breaker

Reset Link

Trip

Paddle

Microswitch

Link

Adjusting

Nuts

Summary of Contents for MicroVersaTrip Plus

Page 1: ...to ANSI Standard C37 59 allowing the retrofitter to properly install the kit and acceptance test the breaker This publication covers installation of MicroVersaTrip Plus and MicroVersaTrip PM Con versi...

Page 2: ...Screw Adjustment 8 Microswitch Linkage 8 Flux Shifter Test 8 Installing the Trip Unit Wiring Harness 10 Installing the Trip Unit Mounting Plate 12 Installing the Current Sensors 13 LA 800 Current Sens...

Page 3: ...pin trip unit connector 10 10 36 pin connector adapter bracket 10 11 Adapter bracket locking tabs 10 12 Installing the push nuts onto the guide pins 11 13 Locking tabs on mounting plate 11 14 Trip uni...

Page 4: ...ng to the breaker both primary and secondary Remove the breaker to a clean well lighted work area WARNING Low voltage power circuit breakers use high speed stored energy spring operating mecha nisms T...

Page 5: ...rated in Figure 1 4 Remove the wires from the original current sen sors CTs if present and slide off the CTs 5 Unscrew the knob on the end of the manual charging handle and pull the handle down part w...

Page 6: ...n of the Micro VersaTrip Plus or MicroVersaTrip PM conversion kit The components provided with the kit are shown in Figure 3 Figure 3 Components supplied with the conversion kit Trip Unit Flux Shifter...

Page 7: ...nt with the breaker reset link 12 4 Install the flux shifter assembly on the right side of the breaker frame where the original flux shifter if present was removed The two mount ing studs should fit t...

Page 8: ...and the self locking nut on the bolt Do not overtighten the nut as the bolt must be free to rotate within the connecting links 2 With the breaker in the OPEN reset position push the lower link 7 down...

Page 9: ...9 Figure 8 Parts sequence for connecting the microswitch link Washers Microswitch Link Breaker Reset Link Flux Shifter Reset Arm 1 4 20 Bolt Self Locking Nut Adjusting Nuts...

Page 10: ...converted breaker is energized or primary injected with the mounting plate not installed or installed improperly damage will result to the trip unit wire harness 36 pin connector and current sensors...

Page 11: ...il the assembly is held firmly against the trip unit mounting plate 5 While holding the adapter bracket and connector assembly firmly in place against the mounting plate bend the two locking tabs on t...

Page 12: ...onnector from the flux shifter 4 Pass the current sensor leads through the hole on the lower left side from the rear of the breaker as shown in Figures 16 and 17 5 If the trip unit is to be connected...

Page 13: ...3 Reattach the primary disconnect assemblies to all the studs if the breaker is unfused or to only the load lower studs if the breaker is fused 4 If the breaker is fused reinstall the fuse assem blies...

Page 14: ...nt door SECTION 5 INSTALLING THE TRIP UNIT Use the following procedure to install the trip unit 1 Pull out the locking lever on the trip unit mount ing plate until it snaps into the open position as s...

Page 15: ...ipment Figures 20 and 21 show the sensor outlines for the 800 A and 1600 A frame sizes respectively 2 Connect the neutral sensor wire harness to the correct taps on the sensor To maintain the same pol...

Page 16: ...16 Figure 21 Neutral sensor outline for LA 1600 breakers...

Page 17: ...the resistance differs considerably from phase to phase the electrical connections may not be properly tightened or it could also indicate improper contact wipe 4 To verify that the breaker has been p...

Page 18: ...t mounted secondary discon nect block Also check for continuity from the breaker mounted neutral secondary discon nect block through to the trip unit wiring har ness connector c If the breaker s lower...

Page 19: ...19 Figure 22 Cabling diagram for MicroVersaTrip Plus and MicroVersaTrip PM trip units with ground fault on four wire loads...

Page 20: ...installation operation or maintenance Should further information be desired or should particular problems arise that are not covered sufficiently for the purchaser s purposes the matter should be ref...

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