York YCWS0313SC, Инструкция по установке, эксплуатации и обслуживанию, Страница: 51 / 104

FORM 201.24-NM2
51
YORK INTERNATIONAL
22 and R407C models. In this mode, the cutout should
typically be set to the saturated refrigerant pressure
equivalent to 10°C below the temperature of the chilled
liquid.
The sludge point of the glycol MUST
be at least 11°C below the equivalent
cutout temperature.
High Compressor Motor Current Cutout:
This cutouts protects against excessively high motor
current and shuts a system down and locks it out after
only a single occurrence of a rise in average motor cur-
rent above the cutout point. Motor current is monitored
using 3 current transformers (CTs) per motor, one on
each phase.
Average motor current is monitored after 7 seconds of
compressor operation. The system will be shutdown if
average motor current exceeds 115% FLA.
When a system is fully loaded, typical
motor currents may be at 60 - 85% FLA
depending on operating conditions.
Low Motor Current Cutout / Motor Protector (high
motor winding temperature cutout) / Mechanical High
Pressure Cutout / External Motor Overload:
The low motor current cutout prevents a compressor
motor running with less current than would normally
be expected. This may result from loss of refrigerant,
contactor, or power problems as well as from a com-
pressor that is not pumping due to a mechanical mal-
function. Motor current is monitored using 3 current
transformers (CTs) per motor, one on each phase.
Average motor current is monitored after 3 seconds of
compressor operation. From this time the system will
be shutdown if average motor current is less than 10%
of FLA.
Compressor motor protection modules and mechani-
cal high pressure cutouts are fitted to each system. All
these devices stop the compressor by removing power
from its motor contactor coils. This causes the CTs to
sense a zero current draw by the compressor motor and
causes a low motor current fault to be displayed. These
devices operate as follows:
Motor Over Temperature Protection:
The motor protection module protects against exces-
sive motor winding temperature by monitoring 3 or 6
sensors built into the motor windings. If the tempera-
ture becomes excessive, the module will cause power
to be removed from the compressor contactors shut-
ting down the compressor. Sensor trip resistance is 13
kW ± 3 kW. Reset is 3.25 kW ± 0.5 kW.
The module provides current overload protection us-
ing its 3 current transformers to monitor phase current.
The modules DIP switches are Factory set to trip at
120% FLA phase current, i.e. 112% of DIP SW set-
ting, the setting being 107% of FLA. Protection against
phase loss, phase unbalance as well as incorrect phase
rotation is included. The module provides a seven seg-
ment display to define the module status as follows:
0 = NO FAULT
1 = CURRENT OVERLOAD
2 = UNBALANCE > 17%
3 = UNBALANCE > 25%
4 = INCORRECT PHASE ROTATION
5 = OVER TEMP
6 = OUT OF RANGE DIP SWITCH SETTINGS
7 = UNBALANCE > 50%
8 = PHASE LOSS
S Y S # H I G H M T R C U R R
S Y S # H I G H M T R C U R R
S Y S # L O W C U R R / M P / H P
S Y S # L O W C U R R / M P / H P
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