Installation manual

McQuay IM 487-4 111
Maintenance
Terminals
The terminals are spring clamp type. They only require
inserting (see


in Figure 124) and clamping the wire to be
stripped, which offers several advantages over screw
terminals. The clamping is done by inserting a flat-bladed
screw driver (up to 9/64" wide). See


in Figure 124.
• Spring connection does not require torquing and resists
vibration
• Easily identifiable terminal markers
• Built-in test ports on each terminal, up to 2.3 mm diameter
See


in Figure 124.
Figure 124. Terminal connectors
Phase Voltage Monitor (PVM) (see page 84)
The phase voltage monitor is designed to protect three-phase
loads from damaging power conditions. A microprocessor-
based voltage and phase sensing circuit constantly monitors
the three-phase voltages to detect harmful power line
conditions. When a harmful condition is detected, its output
relay is deactivated after a specified trip delay (Trip Delay).
The output relay reactivates after power line conditions return
to an acceptable level for a specified amount of time (Restart
Delay). The trip and restart delays prevent nuisance tripping
due to rapidly fluctuating power line conditions.
Other features:
• LED display to indicate status (see


in Figure 125)
– Loss of phase
– High or low voltage
– Voltage unbalance
– Phase reversal
– Rapid cycling
– Standard 1 to 500 second variable restart delay (see


in
Figure 125)
• Standard 2% to 8% variable voltage unbalance (see


in
Figure 125)
• Standard 1 to 30 second trip delay (see


in Figure 125)
Figure 125. Phase voltage monitor
1
Standard
1–500 second
variable
restart delay
LED display
Standard 2%–8%
variable voltage
unbalance
4
Standard
1–30 second
trip delay