Carrier 30HH - Manual (Page 40)

30HH,HJ
INSTALLATION
Carrier
ELECTRICAL DATA
The 6D73 and 6D75 compressors (30HH,HJ -
015,025,030 models) for 220 volt, 50 cycle ap­
plication are supplied with six lead, part wind­
ing
motors and extra starters to provide part
winding start. This is available for the same
60 cycle units on special order.
Time delay relays are required for part winding
starting.
Staggered starting of multiple compressors is
insured by the step controller camshaft drive
motor and recycle relay. Time delay relays
are not required.
Volts - 3 Phase
60 Cycle
Normal Network
Voltage
Application
Range
Voltage
Limits for
Satisfactory
Operation
208 208 187 to 229
230 220 to 240 198 to 264
460 440 to 480 396 to 528
575 550 to 600 495 to 660
CAPACITY CONTROLS
The 30HH,HJ units are supplied with capacity
controls which cycle compressors and load and
unload cylinders of one compressor to give
capacity control steps shown in Table 12 below.
The capacity controls supplied with each unit
consists of a step controller, a solenoid-operated
cylinder
unloading device (two unloaders on
30HH015 and 30HJ015 units) and a chilled water
temperature controller.
Step Controller - The step controller includes
a small, low voltage motor with clockwise and
counter-clockwise
rotation windings that drive
a camshaft. The factory-set cams operate load
switches which start or stop compressors and
load or unload cylinders. The motor windings
of the camshaft drive motor are energized by
a
balancing relay which contains windings in
the temperature bridge circuit between the
chilled water temperature controller and the
motor balancing potentiometer located at the
end of the camshaft. When the unit is loading
or unloading (counter-clockwise or clockwise
rotation of the camshaft drive motor), one chilled
water
temperature corresponds to one position
of the camshaft. Camshaft rotation is limited in
each direction by limit switches.
The step controller also includes a recycle re­
lay which insures that the camshaft is fully re­
cycled to the unload position at startup or after
a
power interruption. After the camshaft has
recycled to the unload position, the chilled water
temperature
controller takes control and starts
camshaft rotation in the load direction which
starts the compressors in sequence, insuring
staggered compressor starting in every case.
W'hile the unit is operating, the factory cam set­
tings on the step controller protect the compres­
sors against rapid cycling.
A small transformer is provided in the step
controller which supplies 24 volt power to the
camshaft drive motor.
Cylinder Unloading Device - On the 30HH,HJ020
thru 30HH,HJ065 units a single cylinder unload­
ing device is installed on the lead compressor.
The lead compressor is the farthest to the left
when
facing the front of the package, except
30HH,HJ045 units, where the lead compressor
Table 12 - Capacity Control Steps
Model Size
30HH,HJ
015
30HH,HJ
020, 025, 030
30HH,HJ
045
30HH055
30HH,HJ065
Compressors 1 2 3 4
Cylinder Unloading Devices 2 1 1 1
Capacity Control Steps 3 4 6 7
Active Cylinders Per Step 2, 4, 6 4, 6, 10, 12
4, 6, 10, 12,
16, 18
4, 6, 10, 12,
16, 18, 24
Approx. Percent Load Per Step 33, 67, 100 33, 50, 83, 100
22, 33, 55, 67,
89, 100
17, 25, 42, 50
67, 75, 100
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