High Discharge Temperature; Motor Protection Devices; Separator Differential Pressure; Temperature, High Discharge - Gardner Denver EDF-KB Operating And Service Manual

SECTION 4
CONTROLS & INSTRUMENTATION
GENERAL – The Gardner Denver Electra–Screw
compressor is supplied with a factory mounted starter
and complete controls as standard equipment. The
standard control system consists of constant run load/
unload operation, or auto start/timed stop operation.
Lead/Lag operation of two compressors is also pos-
sible without additional equipment. Inlet valve modula-
tion is standard.
PROTECTIVE DEVICES – All compressors incorpo-
rate the following protective devices:
Standard Domestic Motor Protection Devices –
Overload heaters are furnished for the starter in the
voltage range specified. There are three (3) overloads
in the starter of proper size for the starter and its enclo-
sure. An overload trip is indicated by the "MOTOR
OVERLOAD" LED located on the control keypad.
Optional Motor Protective Devices – Wye–Delta
Starter – Overload heaters are furnished for the starter
in the voltage range specified. There are three (3) over-
loads in the starter of proper size for the starter and its
enclosure. Note that motor nameplate current must be
multiplied by .577 for wye–delta starters. Proper starter
coil and contact action is also monitored to ensure
proper operation.
Separator Differential Pressure – The Separator dif-
ferential pressure is continually monitored by the mi-
croprocessor controller. At a differential of approxi-
mately 8 PSI (.6 Bar), the "CHANGE SEPARATOR"
LED located on the control keypad flashes indicating
required maintenance. If the warning is ignored, and
the separator differential continues to increase, the mi-
croprocessor controller will stop the unit at 15 PSI (1
Bar) and the LED will remain on steady. See "Control
System Operation," page 19, for further information on
operation of the microprocessor controller.
High Discharge Temperature – The compressor is
protected from high discharge temperature by two in-
dependent thermistor probes. One probe is located in
the compressor discharge housing to sense compres-
sor discharge air–oil mixture temperature. The second
FIGURE 4–1 – CONTROL SCHEMATIC
13–8–606 Page 17
205EDF797
(Ref. Drawing)