How Inverters Save Energy

In this video IDS MD, Blaise Ford demonstrates how inverters save energy.

In the video Blaise uses our demo rig, otherwise known as the balloon machine, to demonstrate how you can save energy on a centrifugal load, in this case a fan, but it also applies to pumps. The rig comprises of an inverter, a motor, a fan and a damper. Blaise uses the damper to control the air flow and then he uses the inverter to control the air flow and then compare the savings achieved.

The Demo Rig

The dials across the top of the demo rig record: the current taken by the inverter, the output voltage from the inverter and the speed of the inverter. At the bottom of the rig there are some switches that turn the inverter on and off and vary the speed. Blaise uses a balloon as a visual aid to measure the air flow, the height of the balloon represents the flow of air.

Cube Law

The reason we will be saving energy during this demonstration is due to the Cube Law. All centrifugal loads are subject to this law. At 100% speed, we use 100% power. If we slow down by just 20% to 80% speed, we get 80% x 80% x 80% which works out at 50% of the power used. So, we lose 20% flow but save 50% of the power.

Damper Demo

First Blaise uses the damper to control the air flow. When the fan is turned on and the damper is closed to reduce the air flow. Blaise adds the balloon to the air flow stream. The height of the balloon represents the flow and it sits at around 2 feet above the piece of duct. Under this damper control the current drawn is 0.4 Amp which represents the power taken by the inverter.

In the second part of this demonstration, Blaise opens the damper so that the air flow is unrestricted and uses the inverter to slow down the fan to get the required air flow. The first thing you notice is it a lot quieter. Blaise adjusts the speed so that the balloon height matches the same level as in the first demo. Achieving the same air flow as before, but instead of taking 0.4 Amps, the inverter is now taking just 0.15 Amps, which is approximately a third of the power.

This is how inverters can save energy!

Find out How Much Energy You Can Save

If you would like to find out how much energy inverter technology can save when applied to your applications, book an electric motor energy survey. Our engineers will visit your premises and assess your applications, run times and your current energy costs. From this, they will provide a conservative estimate of the amount of energy and therefore, money you can save. Call us on 0115 944 1036 or email [email protected] to book.