Control Panel Components - McQuay SWP Series Installation And Maintenance Manual

Control Panel Components

Control Panel Components
Manual Motor Protector (MMP)
The manual motor protector (MMP) provides coordinated
branch circuit, short circuit protection, a disconnecting means,
a motor controller, and coordinated motor overload protection.
A short circuit indicator with manual reset is mounted along
side of each MMP as a means to differentiate between a short
circuit and overload trip conditions.
The MMP trip points are factory set. Do not change unless the
motor ampacity changes or the MMP is replaced with a new
device with incorrect setpoint adjustment. Any other
non-authorized trip point or setpoint adjustment voids all or
portions of the unit's warranty. Authorized setpoint adjustment
is accomplished as follows
For motors with a 1.15 service factor, rotate the arrow on
1
the dial to correspond to the motor FLA.
See 1 in Figure 29.
#
For motors with a 1.0 service factor, multiply the motor
2
FLA by 0.9; then rotate the arrow on the dial to correspond
to that value.
To reset a tripped MMP, clear the trip by rotating the knob
counterclockwise to the OFF (O) position; then rotate knob
clockwise to the ON (I) position. See Figure 29.
If an overload or a fault current interruption occurs, check
circuits to determine the cause of the interruption.
If a fault condition exits, examine the controller. If damaged,
replace it to reduce the risk of fire or electrical shock.
Other MMP Features:
• Three-position rotary operator: OFF (O)-TRIP-ON (I)
(Figure 29).
• Lockout—tagoutable rotary operator: turn the rotary
operator to OFF (O), slide out the extension arm, and insert a
lockout pin.
• Ambient compensated –20°C to +40°C.
• Single-phase sensitivity: if one phase exceeds setpoint, all
three phases open.
• Trip test: insert a 9/64" screw driver in the test slot
(Figure 29) to simulate a trip.
McQuay IM 937
WARNING
Control Panel Components
Figure 29: Manual Motor Protector
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 Figure 30). Then rotate
lever up to the ON position (see Figure 30).
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 or rotate the lever to the OFF position.
1
Press the handle or rotate the lever the opposite direction to
2
the ON position.
CAUTION
29