Carlyle 05T Application Manual - Page 17

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Carlyle 05T Application Manual

6.0 Motor Temperature Control

6.1 Motor Cooling Control

The motors in the 06T compressors are not located in the
suction gas stream like other compressors. These motors
require cooling to maintain reliable operation. Motor barrel
insulation is recommended on compressors with suction
temperatures below -15°F (-26°C) to prevent frost build-up
on the compressor motor barrel.
All motors must have a steady flow of cooling while in oper-
ation to avoid thermal shock to the motor. There are two
methods for providing this cooling; economizer flow from the
mechanical subcooler or liquid injection directly into the mo-
tor barrel.
When using economizer flow, the superheat leaving the me-
chanical subcooler should be set in the range of 10 to 20°F
(6 to 11°C) superheat above saturated intermediate tem-
perature. For parallel applications, an intermediate header is
Liquid Injec on
LRI
to Rotors
Primary
Motor Cooling
Injec on Valve
Supplemental
Motor Cooling
Injec on Valve
Isola on
Valve
required to distribute economizer gas to each compressor.
A solenoid valve is required to isolate each compressor
from this intermediate header when the compressor is not
operating. This solenoid valve can be controlled with the
LonCEM module.
When using only liquid injection, the 1-ton liquid injection
valve (part # EF28BZ001) must feed liquid refrigerant to the
compressor motor at any time the compressor is in opera-
tion.
For both economizer gas cooling and liquid injection, the
motor may require additional cooling when operating under
high loads. A supplemental liquid injection valve (part #
EF28BZ007) should be installed to provide this additional
cooling. This supplement valve can be controlled with the
LonCEM module.
Liquid Injec on
LRI
to Rotors
Primary
Motor Cooling
Injec on Valve
Isola on
Valve
Liquid Line
from Condenser
Supplemental
Motor Cooling
Injec on Valve
Liquid Line
To Evaporator
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