Trane CVHH CenTraVac, Installation, Operation And Maintenance Manual

Page: 63 / 128

CVHH-SVX001G-EN 63
X39003892001A
N No otte e:: Graphic labels (shown above) are used for CE
application only.
IIm mp po orrtta an ntt::
• Before servicing, disconnect all power
sources and allow at least 30 minutes
for capacitors to discharge.
• All electrical enclosures—unit or remote
—are IP2X.
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).
Figure 40. Option 2—PFCC wires routed through
current transformers
Power
Circuit
1
2
3
Fused
Disconnect
or Suitable
Breaker
Motor Starter
Contactor
Motor
Current
Transformer
Fuses
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.
IIm mp po orrtta an ntt:: 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.
N No otte e:: Refer to starter submittal drawing for location of
incoming wiring to the starter.
P Po ow we err S Su up pp plly y W Wiirriin ng g