# Thread: Energy saving by reduce the voltage input

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## Energy saving by reduce the voltage input

I am interested in finding some articles that will describe the saving bringing by reduce the voltage input (voltage regulator) from 400V/230V down to 360V/210V (50cps).
We tried that lower voltage input on a york chiller last week, but the current raised, so there was no saving in KW. Any Idea how to save KW by reduce the voltage input?

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None. Amount of "work" does not change. The only energy saving sideaffect I can think of when using higher voltage is thinner wires.

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Agreed.

The amount of work done doesn't change with voltage input, only current draw.

Higher voltage = lower current draw.

Wattage doesn't change however.

I doubt that smaller wires would save energy, just lower initial cost.

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Originally Posted by jpsmith1cm
....I doubt that smaller wires would save energy, just lower initial cost.
That's what I meant to say.

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THANKS FOR UR COMMENTS, so the voltage input is a fixed parameter with no change?

How did they handle that in countries with diff voltages like Hong Kong (220V) or Malaysia (240V) ? The run on different amps?

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No.

The power (watts) required to operate something is fixed.

Voltage can be changed (sometimes) this in turn changes the amperage draw of the equipment, but the watts consumed will remain constant.

Volts x amps = watts for a basic resistive load.

Check it out.

7. Originally Posted by Jürgen Reinecke
THANKS FOR UR COMMENTS, so the voltage input is a fixed parameter with no change?

How did they handle that in countries with diff voltages like Hong Kong (220V) or Malaysia (240V) ? The run on different amps?

8. there was a few companies making some type of green power converter. What it did was reshape the sinewave and shifted the power factor my moving the current portion of the wave. Never messed with them much. The electricians that hooked some of them up caused a few compressors to fail.

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## Basic Laws

Think about this. Power (Watts) = I (currrent amps) * R (voltage/resistance) The power of a motor is constant. The voltage change is inversely proportional to the amp draw, in a perfect system. A 115 watt lightbulb uses 1 amp draw @ 115 Volts. A 115 watt light bulb uses a 0.5 amp draw at 230 Volts. The key is to be sure your wire carrying the amperage is big enough to allow the electrons to flow freely. If you've ever pulled high amps through a small underrated extension cord you would understand the problem. They become very hot and give off heat (melt sometimes). Heat is energy lost to the atmosphere, decreasing the efficiency of the motor at the end of the wire, therefore using more electricity to do the same job.

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We tried that lower voltage input test also with a normal 25KW 3 phase motor (water pumps) by setting the voltage input from 400 to 360V. The result was a saving in KW by 8% , better power factor and lower heat. No change in motor speed. We use this also for lifts and escalators with the same result in energy saving. Why the HVAC chillers didn't show this saving in KW?

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Originally Posted by Jürgen Reinecke
We tried that lower voltage input test also with a normal 25KW 3 phase motor (water pumps) by setting the voltage input from 400 to 360V. The result was a saving in KW by 8% , better power factor and lower heat. No change in motor speed. We use this also for lifts and escalators with the same result in energy saving. Why the HVAC chillers didn't show this saving in KW?
What was the nameplate voltage on your motor? Also, did the frequency remain the same in your experiment?

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380V, 50 Hz, Motor speed was the same

13. i am not sure how your setup is, but have you considered the power usage of your "voltage regulator"...you may be using more power "overall" than without it.

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