Return to
Residential Refrigeration
and Front Venting Commercial Refrigeration
Service Manual
4.0
Variable Speed Compressor Specification
Never connect compressor directly to AC power!
Always use specified inverter when testing
compressor!
•
The compressors employed within many of Perlick’s cabinets are on the cutting edge of technology for
reciprocating hermetic compressors. The compressors are variable speed models developed and man-
ufactured by Embraco. Depending on the model of the cabinet, either a VEMY3H, VEMY6H or VEGY7H
will be found powering the refrigeration system. The compressor itself looks like a standard fractional
horsepower hermetic reciprocating compressor. The electrical, overload, relay and capacitor, which
are normally found connected to the compressor pins has been replaced by an electronic box which is
called the inverter.
•
The inverter is an electronic board, which controls the compressor and has to have power to it at all
times for it to function properly. It controls the starting of the compressor and the speed at which it is
running at from 1600 rpm to 4500 rpm. A normal hermetic reciprocating compressor runs at a con
-
stant 3600 rpm. The Digital Temperature Control controls a separate power circuit used as the power
to the inverter driver circuit, which turns the compressor on and off.
•
The inverter is powered by 115-127V 50-60Hz 1 Ph AC. The inverter driver circuit power is also 115-
127V 50-60Hz 1Ph AC power. The inverter converts this to 230V 53-150Hz 3 Ph power to drive the
compressor. The resistance between any combination of the three compressor pins for the HP24”
Series is 16.07 ohms, and the HP48 & HP72” series is 6.4 ohms. The inverter has a plastic 3-pin recep
-
tacle which gets plugged onto the compressor pins (can only be installed one way for proper orienta-
tion). The inverter also comes with a ground wire, which gets plugged onto the compressor ground
lug. The inverter is then mounted to the compressor fence by sliding it down and tipping to the vertical
position. A single fastener is then used to mount it to the fence (do not over tighten as it is fastening
into the plastic inverter housing).
Refrigeration System Repair Instructions
Page 4-1
