Huge numbers of electric motors in British Industry are wasting energy because the benefits of using variable speed inverter drives are still not fully appreciated.  To make understanding clearer,  Mitsubishi Electric UK has developed a simple demonstration video and online virtual demo at their Customer Technology Centre in Hatfield.

Inverters have been available for over 30 years, yet there remain many driven machines in industry that do not have them fitted. Matt Handley, who narrates the video, says: “I estimate up to 70 percent of the machines I see in UK production plants do not use an inverter with their drive motor. If fitted, most suitable applications would achieve payback in well under a year, then carry on saving energy for years to come.

Big energy savings are just sitting there

“I think the trouble is that the decision to not fit inverters is often made by non-technical people, and is to help them that we have built a demonstrator showing energy saving in a very simple and practical way”.  The key behind it is that a small reduction in  motor speed significantly reduces its energy input. For anyone interested in the physics behind read about the Cube Law here.

The demo rig uses two identical motors controlling fans to balance a ball.  The traditional arrangement uses a valve to control airflow, and the other uses a Mitsubishi variable speed drive: a screen is used to display and compare the power consumption of both motors.

“This very clearly shows how much energy is saved, in a way that everyone can understand. If we take readings with the balls at different heights, we can see that the power saved is proportional to the cube of speed reduction.”

In the video, which is viewable at the Energy Saving Drives website. Matt is seen working through the demo rig. It takes about three minutes to run the motors and get the readings. In the second half Matt runs through the theory behind the Cube Law, and demonstrates the OEC (Optimal Excitation Control) function of the Mitsubishi drive for further energy savings. Optimal Excitation Control is an innovation unique to Mitsubishi drives and uses advanced motor mapping algorithms to optimise the motor’s efficiency for a given load.

A virtual display on the Energy Saving Drives  website enables potential installers to run the demo themselves online to explore the potential of inverters. It is designed so that both technical and non-technical people can appreciate inverters’ energy saving potential.”

Energy prices have risen significantly in recent years and are expecting to go yet higher to encourage users to become more efficiency conscious, thus reducing carbon emissions.

“There is now a financial imperative to fit inverters like never before,” says Matt. “We are aware that more and more non-engineers are looking at the issue, so we have made the demonstration accessible and understandable to everyone.”

Go here for the online energy saving calculator

 Go here for energy saving demo on YouTube 

Go here for Mitsubishi Energy savings variable speed drives