power saver

Power-Save Energy Corp. products are responsible for thousands of=20 Americans saving millions of dollars on their utility bills. The Power- Save 1200=E2=84=A2 energy saver save families as much as 25% on their elect= ric=20 bill every month without sacrificing normal energy consumption and the=20 comforts it provides. How the power savers work some say it works of Power factor=20 correction method is it true.

lectric=20

So you're admitting to fraud?

--=20 Keith

electric

I just want to know what is the technology behind this and is this devices are true power savers.

r-

ir electric

They're often nothing more than a pilot light. Sometimes they have=20 MOVs to reduce "spikes". The most believable ones correct PF,=20 except that residential customers aren't charged for poor PF. In=20

--=20 Keith

Actually, there are perfectly legitimate power savers out there.

We picked up a bunch of them at a bankruptcy after they were either wrongly wired, recalled, overhyped, or used where not expected.

A lightly loaded induction motor can definitely have its energy efficiency significantly improved by dinking with a proportional phase control. Freezers are a good candidate.

However the savings ONLY applies to places where lightly loaded induction motors are the bulk of the load. And the savings are hard to amortize if the control unit price exceeds nine dollars or so.

Or the motor is not run a significant fraction of the time.

ISTR some suggestion that they could burn out the motor under the wrong circumstances. Unfortunate if it's a fridge or freezer.

r-

ir electric

Why would a freezer ever have a lightly loaded motor?

Why would you ever design a system where a lightly loaded motor=20 would be running for a significant amount of time?

--=20 Keith=20

In article , Don Lancaster wrote: [....]

Yes, what you do is lower the voltage on the motor when it is lightly loaded. The best way to do this is to have the device connected directly onto the motor. It works better in industrial situations than in home use.

The circuit is very like that of a light dimmer with the triac's firing time controlled by the power factor. When the motor is running under a light load, the voltage to it is reduced to keep some reasonable power factor at the motor. Because of the nature of the triac control, the power factor seen back at the mains is not improved but the losses in the motor are.

In many industrial situations a motor will be run for long periods of time at light load with shortish burst of near full load. The motor has to be sized for the maximum load so most of the time it is seriously over designed.

These devices have to contain a circuit to ensure that no DC component is allowed to flow in the current to the motor. Any polarity imbalance will make for huge losses perhaps to the point of burning out the motor.