070.610-IOM (JUL 21)
Page 14
RWF II Rotary Screw Compressor Units
Installation
Voltage protection
NOTICE
Johnson Controls-Frick does not advise nor support
the use of UPS power systems in front of the
Quantum
™
HD panel.
With a UPS power system providing shutdown protection
for the Quantum
™
HD, the panel may not see the loss of
the three-phase voltage on the motor because the UPS
could prevent the motor starter contactor from drop-
ping out. With the starter contactor still energized, the
compressor auxiliary will continue to feed an Okay signal
to the panel. This will allow the motor to be subjected
to a fault condition on the three-phase bus. Some fault
scenarios are:
1. The three-phase bus has power On and Off in a
continuous cyclic manner which may cause the motor to
overheat due to repeated excessive in-rush currents.
2. Motor cycling may damage the coupling or cause other
mechanical damage due to the repeated high torque mo-
tor bumps.
3. Prolonged low voltage may cause the motor to stall
and overheat before the motor contactor is manually
turned off.
Under normal conditions, the loss of three-phase power
will shut down the Quantum
™
HD panel and it will restart
upon power return. If the panel was in:
• Auto – Compressor motor will return to running as
programmed.
• Remote – The external controller would reinitialize the
panel and proceed to run as required.
• Manual – The compressor will have to be restarted
manually after the three-phase bus fault has been
cleared.
If the local power distribution system is unstable or prone
to problems, there are other recommendations to satisfy
these problems. If power spikes or low or high line volt-
ages are the problem, then we recommend the use of a
Sola® constant voltage (CV) transformer with a line sup-
pression feature. If a phase loss occurs, then you typically
get a high motor amp shutdown. If problems continue to
exist, then an examination of the plant’s power factor may
be in order.
Unless careful design failure analysis is considered in the
implementation of power systems, the alternative solu-
tions provide a safer and less expensive implementation.
In either case, only one Sola
®
may be used per compres-
sor. Each compressor needs to be individually isolated
from each other through a dedicated control transformer.
Sharing a common control power source is an invita-
tion for ground loops and the subsequent unexplainable
problems.
Motor starter package
CAUTION
The motor is supplied with copper ring-type lugs
crimped on the motor leads. These lugs are intended
to be bolted together and wrapped with sufcient in-
sulating tape, in accordance with established national
and local electrical codes and practices.
The removal of these lugs for the use of alternate
connection methods may cause electrical failure, re,
or electrical shock hazards. Therefore, IF THE FAC-
TORY-SUPPLIED LUGS ARE REMOVED OR ALTERED
IN ANY MANNER, THE MOTOR WARRANTY WILL BE
VOIDED.
Motor starter and interlock wiring require ments are shown
in Figure 17. All of the equipment shown is supplied by the
installer unless a starter package is pur chased separately
from Johnson Controls-Frick. Starter packages should
consist of:
1. The compressor motor starter of the specied HP and
voltage for the starting method specied (across-the-line,
wye-delta, or solid-state).
NOTICE
If starting methods other than across-the-line are
desired, a motor/compressor torque analysis must
be done to ensure that sufcient starting torque is
avail able, particularly in booster applica tions. Contact
Johnson Controls-Frick if assistance is required.
2. If specied, the starter package can be supplied as
a combination starter with circuit breaker disconnect.
Howev er, the motor overcurrent protection/disconnection
device can be applied by others, usually as a part of an
electrical power distribution board.
3. The oil pump starter with fuses, or in the case where
the compressor motor is a different voltage from the oil
pump motor, with a circuit breaker disconnect suitable for
sepa rate power feed.
4. A 3.0 KVA control power transformer (CPT) to sup-
ply 120 V control power to the microprocessor control
system and separator oil heaters is included. If environ-
mental condi tions require more than the usual two 500
W oil heaters, an appropriately oversized control trans-
former will be required. If frequent power uc tuations are
anticipat ed or extremely noisy power lines are encoun-
tered, a regulating control transformer should be consid-
ered. Contact Johnson Controls-Frick for assistance.
5. For customer-supplied across-the-line starters, a
shunting device must be installed across the Current
Transformer (terminals 3 and 4).
WARNING
If the shunting device is not installed, the Analog I/O
board on the Quantum
™
HD panel may be severely
damaged at start-up. See Figure 12.
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