62
Enertech Global
IOM, BS/BT Models
E
P
E
L
A
B
C
E
L
E
L
E
P
E
P
NEUTRAL OR
GROUND
E
L
E
L
E
L
E
P
E
P
E
P
I
P
E
P
E
L
A
B
C
E
L
E
L
E
P
E
P
NEUTRAL OR
GROUND
E
L
E
L
E
L
E
P
E
P
E
P
I
P
⚠
CAUTION
⚠
CHECK COMPRESSOR AMP DRAW TO VERIFY
COMPRESSOR ROTATION ON THREE PHASE
UNITS. COMPARE AGAINST UNIT ELECTRICAL
TABLES. REVERSE ROTATION RESULTS IN
HIGHER SOUND LEVELS, LOWER AMP DRAW,
AND INCREASED COMPRESSOR WEAR. THE
COMPRESSOR INTERNAL OVERLOAD WILL TRIP
AFTER A SHORT PERIOD OF OPERATION.
⚠
CAUTION
⚠
ALL VOLTAGE CODE “3” 460V UNITS UTILIZE
A 277V ECM MOTOR WHICH REQUIRES A
NEUTRAL WIRE. THE MOTORS ARE WIRED
BETWEEN THE NEUTRAL AND ONE HOT LEG
OF THE CIRCUIT. SOURCE WIRING MUST BE
WYE (STAR) CONFIGURATION. 3-PHASE
DELTA CONNECTIONS WILL NOT PROVIDE THE
CORRECT WIRING AND WILL CAUSE THE UNIT
NOT TO OPERATE.
Example 1: WYE (STAR) Electrical Circuit
NOTE: Proper Power Supply Evaluation
When any compressor bearing unit is connected to
a weak power supply, starting current will generate
a significant “sag” in the voltage which reduces
the starting torque of the compressor motor and
increases the start time. This will influence the rest
of the electrical system in the building by lowering
the voltage to the lights. This momentary low
voltage causes “light dimming”. The total electrical
system should be evaluated with an electrician and
HVAC technician. The evaluation should include
all connections, sizes of wires, and size of the
distribution panel between the unit and the utility’s
connection. The transformer connection and sizing
should be evaluated by the electric utility provider.
Section 13: Troubleshooting
Unit Electrical Data