Heatcraft Refrigeration Products Air-Cooled Condensers none User Manual download pdf (Page 15)

E Series Motors with Integrated Variable Speed

E Series units use an EC motor/fan blade combination to provide variable speed condenser control. All components required

to run the motor at variable speeds are built into the motor.

Speed Adjustment Characteristics

The EC motor varies it’s speed linearly based on a 0-10V input signal. At 10 VDC, the motor runs at full speed. At 0 VDC, the

motor turns o. A chart of the speed control curve is shown below.

The input control signal can be supplied from any controller that outputs a 0-10 VDC signal. For units with a control signal

supplied from a rack control or other external controller, the unit is provided with a terminal board for control signal wiring.

Units with factory installed proportional pressure controls require no installation wiring.

External Control Signal

Contact control manufacturer for setup of external controller to provide 0-10 VDC control signal. Wire the control signal to

terminal board in unit control box. See Diagram #3 for typical external signal control wiring.

Proportional Pressure Control

Units with factory installed proportional pressure controls use a PI controller to vary the motor speed in order to maintain a

constant desired head pressure. The PI controller has ve user adjustable features:

• Head Pressure Setpoint

• Minimum Output

• Throttling range

• Integration constant

• Reverse acting or direct acting mode of operation

Warning! When connecting the unit to the supply power,

dangerous voltages occur. Do not open the motor within

the rst 5 minutes after disconnection of all phases.

Be sure that the unit is isolated.

Warning! Dangerous external voltages can be present

at terminal KL2 even with the unit turned o.

Warning! With a control voltage fed in or a set speed

value being saved, the motor will restart

automatically after a power failure.

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Heatcraft Refrigeration Products Air-Cooled Condensers none User Manual Page 15