D
NOTICE
Motor Damage!
PFCCs must be wired into the starter correctly.
Failure to do so could cause misapplication of these
capacitors and result in a loss of motor overload pro-
tection and subsequently cause motor damage.
PFCCs must be wired one of two ways as shown as
shown below.
Rule 1 - PFCCs installed downstream of starter con-
tactor, upstream of current transformers.
D
WARNING
Hazardous Voltage w/Capacitors!
Disconnect all electric power, including remote
disconnects and discharge all motor start/run capac-
itors before servicing. Follow proper lockout/tagout
procedures to ensure the power cannot be inadver-
tently energized. For variable frequency drives or
other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge
of capacitors. Verify with an appropriate voltmeter
that all capacitors have discharged. Failure to discon-
nect power and discharge capacitors before servicing
could result in death or serious injury.
Note: For additional information regarding the safe
discharge of capacitors, see PROD-SVB06A-EN or
PROD-SVB06A-FR
Simultaneously disconnect capacitors and load from line
power. If the capacitors are not switched offline when the
load is disconnected, they continue to add capacitance
to the electrical distribution system. A “leading” power
factor—too much capacitance—may eventually develop.
This overprotection causes poor voltage regulation, i.e.,
voltage is high when the circuit is unloaded, then drops
as loads are added.
Motor
Fuses
Enclosed
3-phase
unit
capacitor
Fused
disconnect or
suitable
breaker
1
Power
2
circuit
3
Current
transformer
Motor starter
contactor
Rule 2 - PFCC wires routed through cur-
rent transformers.
Size motor overload protection to account for capaci-
tor-supplied current. Overloads are typically set to mea-
sure the total current drawn by the motor. When PFCCs
are used, they become the source of part of that current.
If the current they provide isn’t registered by the over-
load protectors, potentially damaging amperage can
reach the motor. The simplest way to ensure that the
overloads “see” all current supplied to the motor is to
position the PFCCs upstream of the current transformers
as shown in the preceding figure. If the capacitor con-
nection points are downstream of the current transform-
ers, route the PFCC leads through the current transform-
ers as shown in the following figure. This assures that
the overloads register both line and capacitor-supplied
current.
Motor
Fuses
Enclosed
3-phase
unit
capacitor
Fused
disconnect or
suitable
breaker
1
Power
circuit
2
3
Current
transformer
Motor starter
contactor
Interconnecting Wiring
Typical equipment room conduit layouts with and with-
out unit mounted starters are shown in
and
Important:
Keep in mind that the interconnecting wir-
ing between the starter panel, compressor
and control panel is factory-installed with
unit-mounted starters but must be field-in-
stalled when a remote mounted starter is
used.
See starter submittal drawing for location of incoming
wiring to the starter.
Figure 21. Typical equipment room layout for units with
unit-mounted starters
2
3
1
1. Line side power conduits
2. Unit-mounted starter
3. Unit control panel
44
RELEASED 10/Mar/2020 06:59:20 GMT
