Reactive Power

It doesn't.

In the case of a motor, reactive power is simply a feature of the motor's inductance, it being coils of wire, albeit rotating.

It does not take it. It produces it.

A motor doesn't require reactive power to run. You can operate virtually any 'AC' motor using DC. Think of reactive power as " the grease that makes the Watts flow" usable watts in this case. Reactive power is unusable watts. Cheers

Really? I would like to see you run an AC motor on DC. The motor requires a ROTATING magnetic field. That requires alternating current. To answer the gentleman's question, You can't create the magnetic fields without inductors and as long as you are dealing with AC and inductors, there is going to be reactance. There is no getting away from that.

http://www.youtube.com/watch?v=LJ28NrqnJZ4

and another one: http://www.youtube.com/watch?feature=endscreen&NR=1&v=fV7nX44qR9U

Your welcome.

or: http://www.youtube.com/watch?v=OgYZyZQbh-o&feature=related

I rest my case.

Making a dc motor run on ac, or a ac motor run on dc will allow the armature to rotate. The only practical use is as a toaster with load applied in either case.

True, but the question I was responding to was about running an AC motor on DC. The argument of load or no-load conditions was not the issue.

Cables,wires,overhead line conductors etc have resistance,inductance and capacitance even when they are laid in parallel as in overhead power transmission lines,not only when made in a coil or winding form. Even small pieces of wires used to connect contactors to over current relays etc have found to have capacitance & inductance.

I commend you for your explanation, but If the OP didn't know this basic tenet then they need to hit the books more or change career paths.

Reactive power in the induction motor is the power required to create magnetic field.

This particular power is not converted into mechanical power in the motor. Power absorbed by the motor is expressed in kVA and the power converted is expressed in kW, which is the active power. You have to do numerical exercises to understand this notion thoroughly.

actually they are both Watts. you need to read up on the history of why one wattage was named kVA and and the other kW. They are both WATTS....one is usable (due to its average power) and the other isn't. (due again to it's average power). Pure and simple...stop making this harder than it already is.

All AC machines are made-up of iron laminations to carry the magnetic field either to create change of voltage (Transformers) or to create rotation (Induction Motors). Therefore to magnetize these laminations, it needs magnetization current. This current is purely reactive that lags 90⁰ to active current (in phase with supply voltage). The kind of power consumed by magnetization current required by iron lamination is a reactive power.

Any AC equipment (Transformer & Induction motor) needs reactive power otherwise it will notwork or function.

The amount of reactive power draws from the source to magnetize AC equipment and same amount of reactive power will return back to source after magnetization. This reactive power is burden to source (Generator). To avoid this burden (reactive power) on source, the reactive power is locally supplied by connecting the capacitor bank which neutralizes the inductive current by capacitive current with the result source will be free of inductive current (reactive power) and relief of burden of reactive power.

The designers will limit the magnetizing current (reactive power) from 10% to 15% of the rated current (rated kVA) of the AC Equipment (transformers & induction motors). This magnetization current creates lagging power factor as well as supplies reactive power required by transformers & induction Motors.

There is a difference among kW (Real Power), kVAR (Reactive Power Inductive or capacitive) and kVA (Apparent power).

The relation among them is (kVA)² = (kW)²+(kVAR)^2; If power factor is unity, then kVA= kW and kVAR=0.

Use the "beer/foam" analogy. Reactive power is to the work done by the motor as the foam is to a glass of beer.

If you look at glasses of beer, they all have foam, right? So does that then mean that you REQUIRE foam in order to have beer? No, the foam is the RESULT of the beer being available for you to consume from a vessel (I like flagons myself). So the act of transferring the beer into the flagon results in there being foam, but the foam is not really an ESSENTAIL part of the beer*.

*Unless you believe the tripe you see on some commercials where they make that claim...