Security code

5 top tips for choosing the perfect variable-speed drive

There’s plenty to think about when selecting a variable-speed drive, so make sure you get it right by following our essential guide.

1. Know your application

Consider your application and the demand to be placed on the drive carefully, as the wrong choice can lead to oversizing. Load is usually divided into three classifications:

  • Constant torque occurs when fixed volumes are being handled, such as in screw compressors, extruders, or in straight-line web handling
  • Quadratic loads are the most common load type, which cover centrifugal pumps and fans.
  • Constant power is normally required for rolling and unrolling of material where the diameter changes while surface speed remains constant.

2. Collect performance data

Gather the application’s performance data, which includes system inertia, acceleration/deceleration rates, minimum and maximum speeds plus overload requirements. This allows you to understand certain operational levels, such as the speed range. For instance, if an electric motor is rated for 0 – 100 percent, but actually operates between 10 and 100 percent, you run the risk of oversizing. The only way to discover this is by collecting performance data.

3. Is the drive fully certified?

Variable-speed drives are rated for Ingress Protection (IP) and UL Type enclosures as well as falling under IEC/EN 61800-5-2 legislation. The application must be matched with the relevant enclosure, so if the VSD does not have the proper enclosure rating, it should be placed within one that has.

4. Can the drive deal with the application demand?

The VSD must be able to produce the necessary torque at the required speeds. It also needs to be able to control speed and torque depending on the requirements of the application.

5. Does the drive provide safety?

Your chosen VSD could be responsible for safety in your system after changes in the machinery directive. Although some VSDs have integrated safety functionality, an engineer should be consulted as this may not translate to the new equipment.

By considering these five handy tips when choosing a VSD, you’ll find the ideal drive for your application while keeping equipment costs and operating expenses to a minimum.

However, even by following this advice it can still be tricky selecting the right variable-speed drive. So for details of how Gibbons can provide a full installation, service and maintenance package for ABB variable-speed drives, just call our Drives Manager Alan Roberts on 07966468430 or email

Variable-Speed Drives

Add comment

Back to Blog