Emerson SZO44, SZV44, SZV32, SZO56 manual Oil Cooler Fan Control, Brushless DC Fan

Dual-Compressor Module Installation

2.6.2Oil Cooler Fan Control

The Compressor Module temperature is controlled by managing module oil flow and temperature. The module’s precise temperature control is critical to system performance and equipment life. Maintaining proper temperature control also reduces the possibility of gas condensing into liquids during operation.

•Cooling fans require 24VDC, 4.5A (105 Watts) x 2 (9A 210W total) for the Compressor Module. Fan speed is controlled by a 0-10VDC control signal that is applied to the yellow lead on the fan terminal strip. Standard Compressor Modules use a nonlinear PTC thermistor to monitor oil temperature and provide a speed signal.

•High temperature Compressor Modules use a linear NTC thermistor to monitor oil temperature. This signal is available to support a customer-provided fan speed control circuit.

•All power connections are wired to terminal strips in a junction box on the Compressor Module.

Figure 6 Brushless DC Fan

+24VDC

DC common

RED

Blue

No connection feedback

White

0-10VDC speed signal

Figure 7 Basic Fan Control System

PTC Thermistor

Dropping ResistorIn Thermowell

One Fan 100 K Ohms

Two Fans 60.4 K Ohms

Yellow

Red Wire – 24VDC	Yellow Wire – 0-24VDC	Blue Wire – DC Common
	To fan speed control

The PTC Thermistor is nonlinear and switches to high resistance in the 170-190°F (77-88°C) range.

10 2006SSD-75 R4 (10/10)