Auto/Demand Optional; Lead/Lag Optional; Electrical System; High Air Temperature Safety Switch - Quincy Compressor QMA Series Instruction Manual

Auto/Demand - Optional
Auto/Demand controls accommodates external control
signals from an optionrd Quincy Demand-A-Matic
multiple compressor controller. With the selector
switch in the Local mode, the compressor will operate
exactly as described in the previously mentioned Auto
description.
In the Remote mode, the compressor's pressure switch
is bypassed in favor of the Demand-A-Matic multiple
compressor controller. The compressor will start, build
air, unload and shutdown on time delay as determined
by the Demand-A-Matic controller.
Lead/Lag - Optional (Two Machines only)
This option allows one of two different pressure control
settings to be chosen for a given machine. If the
demand is greater than one unit's capability, the second
compressor will automatically turn itself on until the
excess demand has been satisfied. Again, working with
the standard Auto-Dual control, the lag machine would
time out and turn itself off after the demand dropped.
!wARN~G!
Never assume it is safe to work on the unit
because it is not operating. It maybe in the
~
automatic stand-by mode-and may re-start at
any time Follow all safety instructions in the
Preparing for Maintenance or Sermce SectIon V.
Load/No Load - Optional
In the Load/No Load mode, the compressor does not
modulate the inlet valve. The valve is either fidly open
or closed based on demand. If systems demands change
sharply or include regular periods of air usage at less
than full load, large compressed air storage capacity is
required with this type of control. Without adequate
storage, rapid cycling may occur. This will cause wide
system pressure fluctuations that may atXectthe
performance of equipment using the compressed air.
Load/No Load works with Auto-Dual control to turn the
compressor off during extended periods of no demand.
Electrical Svstem
A diagram of the electrical system is shown in the parts
manual sent with the compressor. A wiring diagram is
also included in the control panel on all Quincy QMA
-.
compressors. NOTE - Due to continuing product
improvements and updates, it is suggested that the
wiring diagram included in the control panel be used
when servicing the electrical controL
Note: Standard drive motors are open drip proof
3600 and 1800 RPM with a maximum ambient
temperature rating of 104!F. They are not suitable
for salt laden, corrosive, dirty, wet or explosive
environments.
The QMA series compressors utilize 460V incoming
power through an across-the-line magnetic starter. A
transformerin the control panel reduces this voltage to
120 VAC for the various controls on the unit. These
controls include the selector switch, pressure switch,
timer, high air temperature safety switches, solenoid
and the various indicator lights. Other incoming line
voltages are available as options. The compressor is
provided with an NEMA 1 enclosure. NEMA 4 is an
option.
Air-ccmled models utilize a second magnetic starter for
starting of the fluid cooler fan motor. This starter is
connected to the main motor starter through an
interlock which insures the fan motor is operating at the
same time as the compressor motor. If the fan motor
starter trips out for any reason, the compressor unit will
shut down.
!WA~~G!
~
High voltage may cause severe personal injury or
death. Disconnect all power supplies before
opemng the electmcal enclosure or serwcmg.
High Air Temperature Safety Switch
A high air temperature (HAT) switch is standard on the
QMA compressor. This switch protects the unit by
sensing unusually high temperatures and shutting the
unit down.
On the QMA 50/50H/60 series the HAT switch is
located on the front of the compressor housing near the
mounting flange to the air/fluid reservoir. In this
position the flow of air/fluid from the compressor is
directed onto the sensing probe of the HAT switch. The
switch) is set to trip at approximately 225° F.
On the QMA 75, 100,125, and 150 the HAT switch is
located in the fluid reservoir. The 100, 125 and 150
units have an additional HAT switch located in the air
discharge line.
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