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5 benefits of variable-speed drives you may not know about

You’ll be aware of the main advantage of variable-speed drives – the power to accurately control the speed of electric motor-driven applications and make substantial energy savings. However, drives offer plenty of other benefits and we’ll look at five of them here.

Controlled acceleration

An electric motor and its driven machine are subjected to great mechanical stress when the motor is started ‘across the line’. When this happens repeatedly, all connected equipment will suffer wear and tear which may lead to premature failure. A variable-speed drive, on the other hand, ensures a smooth, gradual start-up which is essential for many processes such as production lines carrying delicate items and containers.

Mechanical drive components not needed

Mechanical means of controlling speed in motor-driven applications, such as dampers and gearboxes, are expensive, inefficient and more onerous to maintain than variable-speed drives. Running a motor at full speed and then slowing down the driven machinery manually has been compared to pressing the accelerator pedal in a car and braking at the same time. A variable-speed drive ensures that energy is used much more efficiently while reducing the load on machinery.

Adjustable torque limit

Without a variable-speed drive (also known as a variable-frequency drive), the torque applied to a motor means it will try to rotate even if there is a problem (such as a jam) with the driven machinery. In many applications this can result in damage to equipment and products, so having a variable-speed drive connected means that torque can be set to a limit which the motor will not exceed.

Avoid dips and trips

The power demand created by starting an electric motor ‘across the line’ is as much as seven times the motor full-load current. Placing such a huge drain on the power supply can result in voltage dips, causing equipment such as computers, sensors and contactors to trip. Variable-speed drives allow voltage to be gradually increased as a motor starts up, eliminating the threat of dips and trips.

Multi-motor control

A variable-speed drive means multiple motor-driven applications such as fans, pumps and conveyors can be controlled from a single unit, saving valuable space and simplifying controls.

Gibbons are a long-time supplier of ABB drives and other electro-mechanical equipment such as electric motors, pumps and HVAC systems. For more information on variable-speed drives, call Alan Roberts on 07966 468430 or email


HVAC Services, Variable-Speed Drives, Electric Motors, Pumps & Controls

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