McQuay RVSS14 Installation, Operation And Maintenance Manual page 9

Motor Terminal Insulation
It is the installing contractor's responsibility to insulate the compressor motor terminals when
the unit voltage is 600 volts or greater, or in high humidity locations that could cause
condensation on the motor terminals that are at about 50°F (10°C). The required material is
shipped in as a kit (775123601) placed in the motor terminal box on all medium and high
voltage units. It can be ordered for high humidity applications.
This is to be done after the McQuay start-up technician has checked for proper phase sequence
and motor rotation.
Following this verification by the McQuay technician, the contractor should apply the
following items.
Materials required for 600+volts or high humidity:
1. Loctite® brand safety solvent (12 oz. package available as McQuay part number
350A263H72)
2. 3M™ Co. Scotchfil brand electrical insulation putty (available in a 60-inch roll as
McQuay part number 350A263H81)
3. 3M Co. Scotchkote™ brand electrical coating (available in a 15 oz. can with brush as
McQuay Part Number 350A263H16)
4. Vinyl plastic electrical tape
The above items are also available at most electrical supply outlets.
Application procedure:
1. Disconnect and lock out the power source to the compressor motor.
2. Using the safety solvent, clean the motor terminals, motor barrel adjacent to the
terminals, lead lugs, and electrical cables within the terminal 4OX to remove all dirt,
grime, moisture and oil.
3. Wrap the terminal with Scotchfil putty, filling in all irregularities. The final result
should be smooth and cylindrical.
4. Doing one terminal at a time, brush the Scotchkote coating on the motor barrel to a
distance of up to 1/2 in. around the terminal and on the wrapped terminal, the rubber
insulation next to the terminal, and the lug and cable for approximately 10 in. Wrap
additional Scotchfil insulation over the Scotchkote coating.
5. Tape the entire wrapped length with electrical tape to form a protective jacket.
6. Finally, brush on one more coat of Scotchkote coating to provide an extra moisture
barrier.
General Wiring Practice
Wire groups
Signal wiring refers to wires connected to the control terminals that are low voltage, below
15V.
• Shielded wire is required to prevent electrical noise interference from causing
improper operation or nuisance trips.
• Signal wire should be rated for at least 300V.
• Keep signal wire as far away as possible from control and power wiring.
Control wiring is wiring connected to the control terminal strip that carry 24V to 220V.
• Use only UL or CSA recognized wire.
• Use copper wire rated for 60/75°C.
• Power wiring to the motor must have the maximum possible separation from all other
wiring. Do not run control wiring in the same conduit; this separation reduces the
possibility of coupling electrical noise between circuits. Minimum spacing between
metallic conduits containing different wiring groups should be three inches (76 mm).
• Minimum spacing between different wiring groups should be six inches (152 mm).
IOMM Starter 9