McQuay RAH 047C Installation And Maintenance Manual page 112

Maintenance
Circuit Breaker
Circuit breakers are installed upstream of all VFDs to provide
short circuit protection. These breakers are not adjustable.
To reset a tripped circuit breaker: Clear the trip by rotating the
lever down to the OFF position (see
lever up to the ON position (see
Breakers, like MMPs, have three distinct modes of operation
which are clearly indicated by the handle position. The
positions are ON (usually up, OFF (usually down), and
TRIPPED (midway). Some circuit breakers may have a push-
to-test button.
Reset After Tripping Information
If a circuit breaker has tripped due to an overload or a fault
current (short circuit), prior to resetting, the connected wiring
circuits must be checked to determine the cause of the
interruption.
If a breaker is tripped, the handle/lever will be halfway
between the OFF and ON positions. To reset a tripped circuit
breaker:
Press the handle/rotate the lever to the OFF position
1
(Figure 126).
Press the handle/rotate the lever the opposite direction to
2
the ON position (Figure
In certain applications the circuit breaker may be mounted
upside down. Therefore, when the handle is in the DOWN
position it may not be turned OFF. The handle position
corresponds to ON and OFF text clearly printed on the face
of the unit. Be sure the mounting orientation and desired
handle position is verified prior to performing service on the
equipment. Only qualified service personnel should work on
this equipment. Improper position of the breaker handle
during service may result in electric shock which will cause
severe personal injury or death.
Figure 126: Circuit Breaker
112
Figure 126). Then rotate
Figure 126).
CAUTION
126).
DANGER
Field Wiring Terminals
All field wiring terminals are spring clamp type, which offer
several advantages over traditional screw-type terminals:
• Spring connections do not require torquing
• Spring connections resist failure due to vibration
• Easily identifiable terminal markers
• Combination spring release and square test ports
To insert a wire to the terminal connector:
Insert a small flat-blade screwdriver into the square hole
1
("1" in Figure 127) adjacent to the desired wire location
("2" in Figure 127) to open the spring clamp.
Strip approximately 1/2" of insulation from the wire.
2
Insert the stripped wire into the wire terminal ("2" in
3
Figure 127).
Remove the screwdriver to close the spring clamp.
4
Figure 127: Terminal Connectors
1
2
2
1
2
1
McQuay IM 987