16 Concentric offers a complete line of Fan Drive electronic controls that interface directly with the electrohydraulic Fan Drive packages. These range in complexity from simple proportional plug and play controls that plug directly into the electrohydraulic valve coil, to stand alone electronic control packages that operate the entire fan drive control system. The controls illustrated demonstrate the spectrum of features available to the OEM. Concentric will assist the OEM in the control specification to achieve the optimum system for the specific vehicle. GENERAL OPERATION OF THE Concentric FAN DRIVE CONTROLLERS Fan drive controllers are designed to control the pressure relieving electro-proportional cartridge valves as part of a proportional fan-drive system. Since fan torque is a cubic function relative to speed, it is more economical to control fan speed using pressure control than flow control. These controllers range in sophistication from simple on-off inputs to multiple sensor proportional inputs and are designed to fit the needs of rugged offhighway vehicles. The controllers illustrated operate on the principle that temperature is to be proportionally controlled between design set points. They provide the necessary output to the electrohydraulic proportional valve in the fan drive system allowing precise fan motor speed correlated to temperature. The inputs can range from a temperature switch providing a voltage input to the controller, to an analog sensor input correlated to temperature. The controllers illustrated in this catalog are typical of the two types developed specifically for fan drive systems. However, special controllers can be developed for higher volume OEM applications. INTEGRAL PLUG-IN CONTROLLERS DESCRIPTION These controllers are designed for single input temperature control. They consist of a series of convenient, plug-mounted control amplifiers for controlling the fan drive proportional valves. These valve solenoids and controllers have DIN 43650/ISO 4400 electrical connectors. These controllers come in a variety of input and output configurations and adjustments. OPERATION This control module utilizes high frequency switching (PWM) to supply a proportional valve solenoid with an input signal that is proportional to an external signal. The external signal can be from a 10K potentiometer, 0–5 VDC, 0-10 VDC, 0–20 mA, or from other pre-set levels. NOTE: Simplified controllers are also available (re: ramping only) NOTE: These controllers fail to full fan speed mode. TYPICAL FEATURES • Mounts directly to solenoid coils with DIN 43650A connectors. • IP65 internal protection (IEC529). • Adjustments accessible with a removable cover. • No internal fuses; circuit limits current electronically. • Short circuit proof and reverse polarity protected. • Connector can be disconnected from coil when powered. • Maximum current adjustment does not affect minimum current setting. • Independent ramp adjustments and internal supply for potentiometer. • Fails to full fan speed. Controls Capability quality products for mechanical & fluid power jbj Techniques Limited, www.jbj.co.uk quality products for mechanical & fluid power ~ jbj Techniques Limited, www.jbj.co.uk UK distributor for Concentric Hydraulics
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