Motor Driven Load

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Load Characteristics

Constant Torque Loads

In this load characteristic, the torque is constant across the entire speed range. The power is therefore directly proportional to the speed and therefore, reducing the speed will also reduce the power required in a linear fashion.

e.g. screw compressors and conveyors

Constant torque.png

Variable Torque Loads

Also called quadratic torque loads, the torque of the load is proportional to the square of the speed. The load power is therefore proportional to the cube of the speed.

e.g. centrifugal pumps, fans and blowers

Variable torque.png

Constant Power Loads

In this load characteristic, the power output of the load is constant across the entire speed range, and therefore torque requirements are high at low speeds.

e.g. Centre driven winders and machine tool spindles

Constant power.png

Constant Torque / Power

This load characteristic is a combination of constant torque in one speed range and constant power in another. e.g. paper making machines

Constant torque power.png

High Starting Torque - Constant Torque

This load characteristic has high torque at starting and low speeds, followed by constant torque at higher speeds.

e.g. extruders and positive displacement pumps

High start torque.png