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9 October, 2019

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VSD calculators offer a choice of pocket-sized formats

09 October, 2010

ABB has released more details of its free energy calculator application (app) for the Apple iPhone, iPad and iPod Touch, and its slide rule that calculates the savings possible when converting a DOL (direct-on-line) motor to variable speed drive (VSD) control.

The Apple app (above) calculates the energy savings possible when using VSDs to control motors. It allows users to make quick comparisons between motors controlled by VSDs and running direct-on-line. The user simply specifies their industry, operating duty profile, electricity costs, and the motor’s characteristics and running hours. The app then estimates how much CO2, energy and money could be saved (in three currencies) by using a drive to control the motor. 

Once the savings have been worked out, the app displays the most suitable ABB drive. The user can then click through to a product summary and place an enquiry or ask for more information.

One side of the pocket-sized slide rule (above) provides data for selecting the rating of a DOL motor. A window shows the typical running costs and kWh if the motor is operated at full speed. The energy consumption is also converted to the equivalent number of high-efficiency light bulbs. By turning the slide rule over, the user can see the effect of applying a VSD to the application.

The slide rule can compare the energy consumption and costs of a motor running at full speed with no damper or throttle, with those of a motor controlled by a VSD with 20% speed reduction. Users can compare the cost and KWh usage of these two cases based on running the motor for anything from 8 hours a day over a five-day week, up to continual 24-hour usage over a whole year. 

For example, a 110kW motor without any speed control consumes 770,880kWh when running for 8,760 hours per year. The slide rule shows this is the same as running 6,111 efficient light bulbs. However, adding a VSD cuts the energy consumption to 376,189kWh per year – the same as running 2,689 low-energy bulbs.

“All too often we see campaigns encouraging us to switch off the lights,” says Steve Ruddell, ABB’s UK energy spokesperson. “While I endorse any initiative that saves energy, the impact of installing just one VSD on one 110kW motor is the same as switching off 3,422 high-efficiency light bulbs. How amazing is that!”.

The slide rule is available by emailing your contact and address details to or calling 07000 Drives (07000 374837) in the UK. To download the Apple app, visit Apple’s App Store or and click on the Energy Calculator App link.

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