What Is a Compressor Pulley?

A compressor pulley is a device used to provide power to a pump from a motor. Commonly created from a cast iron or alloy metal, the compressor pulley also uses a spoke design from the center hub of the pulley to the outer ring that acts as a fan to cool the compressor pump. Many manufacturers use the compressor pulley to balance the compressor in order to achieve a smooth operating pump. Another typical feature of this pulley are multiple belt grooves to provide slip-proof operation when under extreme load.

Many compressors use an electric motor to provide power to the pump. These machines commonly use a drive pulley set that consists of a motor and compressor pulley and drive belts. Designed to operate in pairs, the motor pulley is usually smaller in diameter than the compressor pulley and is commonly manufactured of the same material as the compressor unit. V-type belts or cog belts are the most commonly used style of belts and when in use, the V-type belts are usually operated in multiples of two or three. The use of multiple belts provides maximum contact area between the pulleys and the belts, thereby eliminating slippage under severe resistance.

One frequently`used design in the compressor pulley is a spoke treatment that resembles the blades of a fan. As the pulley spins, the blades push fresh air across the compressor cooling fins, reducing any heat generated from friction within the compressor cylinders. Heat is a common byproduct of compressing air/gasses, and this heat can damage the compressor if allowed to go untreated. When used in some dirty environments, such as a paint and body shop, the fan also keeps the air moving across the intake filter of the compressor, reducing plugging of the filter and reducing changing intervals.

When used in an automotive application that causes the compressor to be operated off of the engine's operating accessories, the compressor pulley routinely uses an electric clutch drive pulley design. This style of pulley allows the belt to turn the clutched pulley at engine speed without engaging the compressor. When the compressor is needed, as is the case with an air conditioning compressor pump, the electric clutch apparatus can be activated by flipping a control switch on the vehicle's dashboard. The clutch is engaged, effectively driving the compressor at engine speed and powering the air conditioning unit to cool the passenger compartment of the vehicle. When no longer needed, the switch is turned off, thus cutting the power to the clutch, disengaging it and allowing the drive belt to once again ride freely on the spinning compressor pulley.