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Figure 42. Option 2—PFCC wires routed through
current transformers
Fused
Disconnect
or Suitable
Breaker
Transformer
1
Power
2
Circuit
3
Enclosed
3-phase
Capacitor
Unit
Size motor overload protection to account for capacitor-
supplied current. Overloads are typically set to measure
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 is not registered by the overload
protectors, potentially damaging amperage can reach the
motor. The simplest way to ensure that the overloads
detect all current supplied to the motor is to position the
PFCCs upstream of the current transformers as shown in
the preceding figure (Option 1). If the capacitor connection
points are downstream of the current transformers, route
the PFCC leads through the current transformers as shown
in the preceding figure (Option 2). This ensures that the
overloads register both line and capacitor-supplied current.
Interconnecting Wiring
Typical equipment room conduit layouts with and without
unit-mounted starters are shown in the following two
figures.
Important: The interconnecting wiring between the starter
panel, compressor, and control panel is
factory-installed with unit-mounted starters.
However, when a remote-mounted starter is
used, the interconnecting wiring must be field-
installed.
Note: Refer to starter submittal drawing for location of
incoming wiring to the starter.
CDHH-SVX003C-EN
Current
Motor
Motor Starter
Contactor
Fuses
Figure 43. Typical equipment room layout for units
with unit-mounted starter
1
3
2
1. Line side power conduits
2. Unit-mounted starter
3. Unit control panel
Figure 44. Typical equipment room layout for units
with remote-mounted starters
1
4
2
3
6
7
5
1. Line side power conduits
2. Remote-mounted starter
3. Unit control panel
4. Inter-processor communication (IPC) circuit conduit
less than 30V (and current transformer/potential
transformer [CT/PT] wiring for starters by others)
Note: Must enter the low voltage Class 2 portion of the unit
control panel (1000 feet [304.8 m] maximum).
5. Motor terminal box
6. 115V control conduit
Note: Must enter the higher than 30 Vdc Class 1 portion of
the until control panel.
7. Lead power wiring
Note: Refer to the unit field connection diagram for
approximate unit control panel knock out locations.
To prevent damage to the unit control panel
components, do NOT route control conduit into the
top of the box.
Power Supply Wiring
63
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