RTAC-SVX005A-EN
31
Unit Voltage and Amperage
Checks
WARNING
Live Electrical Components!
Failure to follow all electrical safety precautions when
exposed to live electrical components could result in
death or serious injury.
When it is necessary to work with live electrical
components, have a qualified licensed electrician or
other individual who has been properly trained in
handling live electrical components perform these
tasks.
Electrical power to the unit must meet stringent
requirements for the unit to operate properly. Total voltage
supply and voltage imbalance between phases should be
within the following tolerances.
Voltage Supply
Measure each leg of supply voltage at all line voltage on
circuit breaker. Readings must fall within the voltage
utilization range shown on the unit nameplate. If voltage on
any leg does not fall within tolerance, notify the power
company to correct this situation before operating the unit.
Inadequate voltage to the unit will cause control
components to malfunction and shorten the life of electrical
components and compressor motors.
Voltage Imbalance
Excessive voltage imbalance between phases in a three-
phase system will cause motors to overheat and eventually
fail. Maximum allowable imbalance is 2 percent. Voltage
imbalance is defined as follows:
% Voltage Imbalance =
100 x V
A
— V
D
V
A
where V
A
=
V
1
+V
2
+V
3
(Avg Voltage)
3
• V
1
, V
2
, V
3
= Line Voltages
• V
D
= Line Voltage that deviates the farthest from V
A
.
Example: If the three voltages measured at the line voltage
side of the circuit breaker are 453 volts, 470 volts, and 467
volts, the average (V
A
) would be:
453+470+467
= 463 volts
3
The percentage of imbalance is then:
100 X [463 – 453]
= 2.2%
463
The 2.2 percent imbalance that exists in the example
above exceeds maximum allowable imbalance by 2.0
percent. This much imbalance between phases can equal
as much as 20 percent current imbalance with a resulting
increase in winding temperature that will decrease
compressor motor life.
If the voltage imbalance is over 2 percent, notify the proper
agencies to correct the voltage problem before operating
this equipment.
Electrical Cable
Table 3. Technical cable data, size 2/0
Conductor size: 2/0 AWG
Ampacity: 265 Amps per conductor
(a)
Construction: Rope stranded copper conductor,
colored-coded (blue, red, green and
black) connectors on each end.
Insulation is composed of water, acid,
ozone and chemical resistant
thermoplastic rubber compound.
Temperature rating (°F): -49 to 194
Weight (Lbs./100 Ft.): 64
Conductor nominal OD (in.): 0.8200
Cable rating: UL Rated at 2000 volts, C(UL) 600 volts
for continuous use.
(a)
The values listed above are based upon ambient temperature @ 86°F, where
the individual conductor is not installed in raceways or buried (Reference NEC
Code, Table 400.5 (A)(2), 2014 Edition).
Installation - Electrical
To Next Page
Loading...
Need help?
General
