7
Instruction Booklet
IB157001EN
Effective May 2015
Fixed capacitor banks (Unipump, Unipak, and Unipak
detuned filter) low voltage (600 V and below), NEMA 1
NEMA 3R (outdoor) enclosed versions
EATON
www.eaton.com
Electrical connections
Capacitors should be ideally connected to as close to the inductive
load as possible for optimum power factor correction .
At load
Three options exist for installing capacitors in the motor circuit .
See
Figure 2
to determine which option is best for each motor .
Location A—motor side of overload relay
•
New motor installations in which overloads can be sized in
accordance with reduced current draw required .
Location B—line side of starter
•
Existing motors when overload rating surpasses code
Location C—line side of starter
•
Motors that are jogged, plugged, reversed
•
Multi-speed motors
•
Starters with open transition
•
Reduced voltage starters
At the service feeder
Main bus
or feeder
Capacitor
bank
Fused switch or
circuit breaker
Figure 3. Service entrance schematic
When correcting entire plant loads, capacitor banks can be installed
at the service entrance, if load conditions and transformer size
permits . If the amount of correction is too large, some capacitors
can be installed at individual motors or branch circuits .
If the amount of connected capacitance is greater than required,
a leading power factor may result during light load conditions .
A system evaluation may be required to determine if the leading
power factor and associated voltage rise during light load conditions
are acceptable .
When capacitors are connected to the bus, feeder, motor control
center, or switchboard, a disconnect and overcurrent protection
must be provided .
Startup and commissioning
Connect power to the capacitor bank (energize through upstream
switch) . Using an ammeter, measure capacitor current in each phase
and verify that it is consistent (±10%) with the rated current (see
Table 7
) . Using a voltmeter, measure phase-to-phase voltage and
verify that it is consistent (±10%) with the voltage rating stated on
the nameplate .
The full load ampacity of the capacitor is calculated as:
Full Load Amps = Rated kVAR x 1000 / (Sq-rt 3 x Rated Voltage)
It is recommended that both the voltage and the current be
measured again after approximately 24 hours of operation .
During normal operation, cleared fuse indicator lights will NOT
be illuminated . An illuminated lamp indicates that a fuse has
cleared (opened) .
Alternate system voltages and frequencies
Power factor capacitors may be applied to power systems with
actual voltage equal to or less than the rated capacitor voltage but
the effective kVAR will be reduced . Unfiltered capacitors may also
be used on either 50 Hz or 60 Hz systems but again with de-rating .
Contact factory for availability of 50 Hz filtered capacitor banks, as
the reactors are frequency specific . Never connect capacitors to a
system with a higher voltage than the capacitor rated voltage .
Actual kVAR = Rated kVAR x (Applied Voltage / Rated Voltage)^2 x
(Applied Frequency / Rated Frequency)
