49
User Manual MN013016EN
Effective July 2022
Magnum PXR and Power Defense SB low
voltage power circuit breakers user manual
EATON www.eaton.com
Side-to-side
ledge
Side-to-side
ledge
Contact wear
inspection area
(ledge not visible
under contacts)
Contact wear
inspection area
(ledge NOW becoming visible
under contacts)
Contact wear indicator—
contacts closed and in good condition
Contact wear indicator—
contacts closed and wear is indicated
Figure 79. Use of contact wear indicator with circuit breaker closed
Internal mechanism inspection
Table 17. Pre-inspection conditions
Device Position of poles Mechanism Device position in cassette
Fixed Open Closed Charged Discharged — — — —
Drawout Open Closed Charged Discharged Connected Test Disconnected Removed
Procedure
1. Inspect the breaker for nicked wires, cracks in plastic parts,
and loose screws. Screws or bolts should be tightened to levels
outlined in Table 18. Loose screws inserted into plastic parts will
require thread-locking compound (such as Loctite 242).
All nicked wiring should be replaced or repaired in accordance
with accepted industry practices.
2. Ensure that the torque values of the operating mechanism
and motor mounting hardware are within the recommended
values in Table 14.
3. Inspect all sliding or rolling parts for cleanliness and adequate
lubrication. Refer to Table 19 and Figure 80—Figure 85.
Table 18. Magnum PXR and PD-SB breaker torque list
Subassembly lb-in Nm
Arc chute 35–45 3.95–5.08
Front cover 25–35 2.82–3.95
Rear housing 75–85 8.47–9.60
Motor operator 75–85 8.47–9.60
Current sensor cover screws 18–22 2.03–2.49
Fixed mount feet bolts 75–85 8.47–9.60
Primary disconnect 75–85 8.47–9.60
Table 19. Greases used on Magnum PXR and PD-SB
Grease type Description
Magnalube
®
-G
Eaton standards #53701AI
Color Green
Manufactured by Saunders Enterprises inc.
11-51 44th Road, Long Island City, New York 11101
Phone (718) 729-1000
Fax (718) 729-2690
www.magnalube.com
Molykote
®
Eaton standards #53701QB
Color Black
Manufactured by Dow Corning Company
Midland, Michigan 48686-0994
(989) 636-1000
www.dupont.com/molykote.html
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