Powell Apparatus Service Division
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PROCEDURE –
MP1010
PowlVac Circuit Breaker, “Standard” Mechanism)
“Main Trip Prop” Removal and Replacement Procedure
The following instructions outline the removal and replacement of “Main Trip-Prop” assembly on
PowlVac standard and replacement breakers equipped with standard type “PVS PowlVac stored
energy” spring charge mechanisms. This procedure is applicable for all ratings and models of these
breakers. Refer to the specific PowlVac Instruction Bulletins for additional breaker details.
Important: This procedure does not apply to Powell breakers equipped with “PVCB” or “AT” type stored energy mechanisms.
Please refer to applicable Powell instruction bulletins for instructions pertaining to these breaker types.
IMPORTANT SAFETY NOTES:
All breakers must be removed from service prior to performing any maintenance. Before any adjustments,
servicing, parts replacement, or any other act is performed requiring physical contact with the electrical
working components or wiring of this equipment, the POWER SUPPLY MUST BE DISCONNECTED.
Only qualified personnel should attempt performing maintenance on any power circuit breaker.
.
WARNING
WHEN ANY MAINTENANCE PROCEDURE REQUIRES THE OPENING OR CLOSING OF THE CIRCUIT BREAKER
OR THE CHARGING OF ANY OF THE STORED-ENERGY MECHANISM SPRINGS, EXERCISE EXTREME
CAUTION TO MAKE SURE THAT ALL PERSONNEL, TOOLS, AND OTHER OBJECTS ARE KEPT WELL CLEAR
OF THE MOVING PARTS OR THE CHARGED SPRINGS. FAILURE TO DO THIS MAY CAUSE SERIOUS DAMAGE
OR INJURY TO THE CIRCUIT BREAKER OR PERSONNEL.
Main Trip Prop
Assembly
Jack-Shaft
Assembly
“Open-Close
Flag Indicator”
Assembly
Spring Charge
Indicator
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
m.
n.
Secondary Trip-Prop Adjusting Screw
Secondary Trip-Prop Shaft
Secondary Trip-Prop
Secondary Linkage Roller
”Fundamental Link” Assembly
Main Cam Roller
Reset Spring
Camshaft
Main Closing Cam
Center-Phase Operating Lever
Jackshaft
”Main Trip-Prop” Assembly
Main Trip Prop Roller
Main Trip Prop Adjusting Screw
Main Trip Prop
Torsion Spring
Figure-1
Standard PowlVac Circuit Breaker Stored Energy Mechanism – (“Main Closing Spring” Removed)
Rev. 1, April 17, 2006 - Page 1 of 7
2006 by Powell Electrical Manufacturing Company. All rights reserved.
PO Box 12818, Houston, Texas, 77217-2818, 713-944-6900, info@powellservice.com, www.powellservice.com
Powell Apparatus Service Division
PROCEDURE –
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MP1010
PowlVac Circuit Breaker, “Standard” Mechanism)
“Main Trip Prop” Removal and Replacement Procedure
Tools / Materials Required For
Performing This Procedure: ⇨
IMPORTANT
Open-End Wrench or Ratchet / Socket Set, Tape Measure, Needle-Nose Pliers,
Screwdriver Set, E-Clip retaining ring removal tool, Main Trip-Prop Replacement Kit, Copy
of applicable PowlVac Circuit Breaker Instruction Bulletin
Please carefully review and understand all steps before initiating the procedure.
1. Move the breaker to a convenient, well lighted working location.
2. Unbolt and remove the breaker’s front cover.
3. Remove the main closing spring assembly from the breaker, as-per PASD maintenance procedure MP1009.
4. Unscrew and remove the nameplate / indicator cover plate from the breaker and set aside.
5. Locate the main trip prop assembly at the upper rear center of the mechanism assembly. The main trip-prop
shaft runs horizontally through both sides of the mechanism assembly and is secured on each side with E-ring
retaining clips.
Left and Right
Thrust Washers
Left
Spacer
Right E-Ring
Retaining Clip
Right
Spacer
Main TripProp Shaft
Torsion
Spring
Left E-Ring
Retaining Clip
Spring
Anchor
Main Trip-Prop Assembly
Main Trip-Prop; Location and Component Assembly Layout
“Replacement” Main Trip Prop
Notched ID groove runs across
Top Center Plate
“Original” Main Trip Prop
(Un-Notched Top Center Plate)
Identifying Physical Difference between “Original” and “Replacement” Main Trip-Prop Assemblies
Rev. 1, April 17, 2006 - Page 2 of 7
2006 by Powell Electrical Manufacturing Company. All rights reserved.
PO Box 12818, Houston, Texas, 77217-2818, 713-944-6900, info@powellservice.com, www.powellservice.com
Powell Apparatus Service Division
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PROCEDURE –
PowlVac Circuit Breaker, “Standard” Mechanism)
“Main Trip Prop” Removal and Replacement Procedure
Removal of the original Main Trip-Prop Assembly
6. Locate the left end of the torsion spring.
Using pliers pull the left end of the torsion
spring off of and around the spring anchor on
the right side of the main trip prop assembly.
Allow the spring to release and “snap” back
against the rear mounting bar.
7. Locate and remove the left E-Clip retaining
ring, (“E-Clip”) from the left end of the main
trip-prop shaft.
Note: The E-Clip on the right end of the main trip-prop
shaft does not have to be removed.
Rev. 1, April 17, 2006 - Page 3 of 7
2006 by Powell Electrical Manufacturing Company. All rights reserved.
PO Box 12818, Houston, Texas, 77217-2818, 713-944-6900, info@powellservice.com, www.powellservice.com
MP1010
Powell Apparatus Service Division
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PROCEDURE –
MP1010
PowlVac Circuit Breaker, “Standard” Mechanism)
“Main Trip Prop” Removal and Replacement Procedure
8. Using pliers or a screwdriver, slide the main
trip-prop shaft towards the right until the right
end of the shaft is 2 ¼” from the mechanism
right side plate. Remove the left spacer and
thrust washer from the shaft and set aside.
2 ¼”
←→
9. Continue sliding the main trip-prop shaft to
the right until the shaft’s right end reaches
exactly 3” from the mechanism right side
plate. The main trip-prop and right thrust
washer can now be removed from the left
end of the shaft.
Note:
The torsion spring and right spacer do not have to be
removed from the assembly.
Note:
The existing main trip-prop is to be discarded after
being removed from the breaker. It will not be used
again.
3”
←--→
Removal of the existing Main Trip-Prop is now complete. Please proceed to the Installation section on the next page.:
Rev. 1, April 17, 2006 - Page 4 of 7
2006 by Powell Electrical Manufacturing Company. All rights reserved.
PO Box 12818, Houston, Texas, 77217-2818, 713-944-6900, info@powellservice.com, www.powellservice.com
Powell Apparatus Service Division
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PROCEDURE –
PowlVac Circuit Breaker, “Standard” Mechanism)
“Main Trip Prop” Removal and Replacement Procedure
Installation of the Replacement Main Trip-Prop Assembly
Note:
The right spacer and torsion spring should still be
remaining on the right side of the main trip-prop shaft.
10. Slide the thrust washer removed in the last
step back over the left end of the main tripprop shaft. Take the replacement “notched”
main trip-prop assembly and position it with
the notched groove facing upward and align
the shaft bearing hole with the left end of the
main trip-prop shaft.
Slide the shaft to the left and through the
main trip-prop bearing hole until the left end
of the shaft is even with the left side of the
replacement main trip-prop.
11. Re-position the left spacer and left thrust
washer between the left side of the main
trip-prop and the left side of the mechanism
assembly. Slide the shaft back to the left,
through the washer and spacer until the
E-clip retainer on the right end of the shaft
stops against the mechanism assembly right
side.
Rev. 1, April 17, 2006 - Page 5 of 7
2006 by Powell Electrical Manufacturing Company. All rights reserved.
PO Box 12818, Houston, Texas, 77217-2818, 713-944-6900, info@powellservice.com, www.powellservice.com
MP1010
Powell Apparatus Service Division
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PROCEDURE –
PowlVac Circuit Breaker, “Standard” Mechanism)
“Main Trip Prop” Removal and Replacement Procedure
12. Install a new E-Clip retaining ring to secure
the left end of the main trip-prop shaft at the
left side of the mechanism assembly.
13. Push the lower end of the main trip-prop
downward until the back side touches the
primary trip-prop adjusting screw.
Use pliers to pull and re-position the left end
of the torsion spring around and to the top of
the spring anchor on the right side of the
replacement main trip prop.
Rotate and release the main trip-prop
against the primary trip-prop adjusting screw
to confirm smooth, free operation of the
assembly, (see Figure-1, item: “l” on page-1 of this
procedure).
Caution: Failure to position the torsion spring on the top
of the main trip-prop spring anchor can result
in serious damage to the mechanism assembly
when the breaker is operated.
Rev. 1, April 17, 2006 - Page 6 of 7
2006 by Powell Electrical Manufacturing Company. All rights reserved.
PO Box 12818, Houston, Texas, 77217-2818, 713-944-6900, info@powellservice.com, www.powellservice.com
MP1010
Powell Apparatus Service Division
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PROCEDURE –
MP1010
PowlVac Circuit Breaker, “Standard” Mechanism)
“Main Trip Prop” Removal and Replacement Procedure
14. Re-install the circuit breaker main closing spring assembly as-per PASD Maintenance Procedure MP1009.
15. Replace the nameplate / indicator cover plate and the circuit breaker’s front cover.
16. The breaker should be manually or electrically tested, (charge, close, and trip) to confirm correct operation.
The Main Trip Prop replacement is now complete and the breaker can now be returned to service.
END OF PROCEDURE
Rev. 1, April 17, 2006 - Page 7 of 7
2006 by Powell Electrical Manufacturing Company. All rights reserved.
PO Box 12818, Houston, Texas, 77217-2818, 713-944-6900, info@powellservice.com, www.powellservice.com