Recommended Minimum Cool Down Time After Compressor Is Stopped; Motor Overload Protection; Kriwan Motor Protection Module Troubleshooting - Carrier 38APS025 Manual

while the motor continues to run. After the compressor runs for
some time without pumping gas, the motor overload protector
will open. The longer the compressor runs unloaded, the longer
it must cool before the bi-metal disk resets. See Fig. 159 for ap-
proximate reset times.
To manually reset ASTP, the compressor should be stopped
and allowed to cool. If the compressor is not stopped, the motor
will run until the motor protector trips, which occurs up to 90
minutes later. Advanced Scroll Temperature Protection will re-
set automatically before the motor protector resets, which may
take up to 2 hours.
120
110
100
90
80
70
60
50
40
30
20
10
0
0 10 20 30
Compressor Unloaded Run Time (Minutes)
NOTE: Times are approximate. Various factors, including high humidity, high
ambient temperature, and the presence of a sound blanket will increase cool-
down times.
Fig. 159 — Recommended Minimum Cool Down
Time After Compressor is Stopped

MOTOR OVERLOAD PROTECTION

Copeland* Compressors Models with Electrical Code TF
— Models with a "TF" in the electrical code (i.e.,
ZP182KCETFE) have an internal line break motor overload
located in the center of the Y of the motor windings. This over-
load disconnects all three legs of the motor from power in case
of an over-current or over-temperature condition. The overload
reacts to a combination of motor current and motor winding
temperature. The internal overload protects against single
phasing. Time must be allowed for the motor to cool down
before the overload will reset. If current monitoring to the
compressor is available, the system controller can take advan-
tage of the compressor internal overload operation. The con-
troller can lock out the compressor if current draw is not
coincident with contactor energizing, implying that the com-
pressor has shut off on its internal overload. This will prevent
unnecessary compressor cycling on a fault condition until cor-
rective action can be taken.
Copeland Compressors Models with Electrical Code TW or
TE
CAUTION
The electronic motor protection module is a safety device
that must not be bypassed or compressor damage may
result.
Models with a "TW" or "TE" in the electrical code (i.e.,
ZP182KCETWD or ZP182KCETED) have a motor overload
system that consists of an external electronic control module
connected to a chain of four thermistors embedded in the motor
windings. The module will trip and remain off for a minimum
of 30 minutes if the motor temperature exceeds a preset point
to allow the scrolls to cool down after the motor temperature
limit has been reached. It may take as long as two hours for the
motor to cool down before the overload will reset.
NOTE: Turning off power to the module will reset it immedi-
ately.
40 50 60 70 80 90
Restoring the compressor sooner may cause a destructive
temperature build up in the scrolls.
For this reason, module power must never be switched with
the control circuit voltage.
Current sensing boards monitor to the compressor current.
The ComfortLink control system takes advantage of the com-
pressor overload operation by locking out the compressor if
current draw is not detected. This will prevent unnecessary
compressor cycling on a fault condition until corrective action
can be taken.
Kriwan Motor Protection Module Troubleshooting — Cope-
land models with a "TW" in the electrical code (i.e.,
ZP182KCETWD), have a motor overload system that consists
of an external Kriwan electronic control module. These have
been replaced by the CoreSense* communication module for
motor protection. This section is included for reference, and
contains instructions for replacing the Kriwan module with the
CoreSense module in the field.
Follow the steps listed below to troubleshoot the Kriwan
module in the field. See wiring diagram on terminal box cover,
or Fig. 160.
Do not supply power to unit with compressor cover
removed. Failure to follow this warning can cause a fire,
resulting in personal injury or death.
Exercise extreme caution when reading compressor cur-
rents when high-voltage power is on. Correct any of the
problems described below before installing and running a
replacement compressor. Wear safety glasses and gloves
when handling refrigerants. Failure to follow this warning
can cause fire, resulting in personal injury or death.
Do not manually operate contactors. Serious damage to the
machine may result.
LEGEND
1 — Kriwan Motor Protection Module Power
2 — Kriwan Control Circuit Connections
3 — Motor Thermal Sensor
Fig. 160 — Kriwan Motor Protection Wiring
*Trademarks of Emerson Climate Technologies.
139
CAUTION
WARNING
WARNING
CAUTION
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