POWER CALCULATION whether the receiver is inductive or capacitive

Question

Hello, I am looking for some way to determine whether a given receiver is inductive or capacitive in the AC waveform, I need to determine what I am dealing with, whether it is a coil or a capacitor. Is it possible to calculate exactly with the calculated active, reactive and apparent powers?...

Anonymous · Accepted Answer

A simple matter - the reactive power for the capacitive load is negative, and for the inductive load - positive.

Anonymous · Accepted Answer

How do you want to measure reactive power with a wattmeter (active power meter)? In addition, with reactive power compensation, the active power remains the same and the meter itself always tilts in the positive direction. If it was sent in the opposite direction, it would mean it could flow from the receiver to the network. Mine too. I have already proposed this in post 4. Assuming that the supply voltage is 230VAC, and assuming that it is an inductive load, to compensate it to unity, we must make the capacitor take reactive power of 11.75Var. So it must have an impedance of 4500 ohms. Such a capacitor will have a capacity of 7 * 10 ^ -7 F or 700nF.

Stanislaw elektryk12 · Answer

Buddy, did you give a formula to calculate the capacitive power? Thanks in advance,

Anonymous · Answer

Unfortunately, you will not determine it with ordinary measurements with a multimeter. But there are special meters that measure all voltages, currents and powers, including the type of reactive power. However, you can connect a capacitor bank or a solid coil to the network and check how the current (apparent power) changes by the system.
As for the formula for reactive power, there are many of them. E.g. S ^ 2 = P ^ 2 + Q ^ 2.

bodzio507 · Answer

Did you take these measurements? Is it a three-phase system?

mateusz25109 · Answer

It would be best if you upload a schematic of this circuit. Then it will be easier to help you

Anonymous · Answer

It seems to me that this is an existing installation with dozens if not hundreds of receivers. So the scheme is rather hard.

bodzio507 · Answer

If we have a measurement system, then after deflecting the meter we can determine the nature of the receiver.

Kraniec_Internetów wrote:
It seems to me that this is an existing installation with dozens if not hundreds of receivers.

It is in such systems that the power factor changes every now and then and we have special regulating systems for this.
Do you think hundreds of receivers use 32 W of power and 11 var of reactive power?
I don't normally compensate for that,

Anonymous · Answer

Depends on what meter. Not necessarily. The devices can work continuously with the same power. For example, fans. In fact, I forgot what order of power the question is about.

bodzio507 · Answer

I mean an analog wattmeter. But the digital wattmeter should also show positive or negative power. This is of course possible. But much more often these are systems in which the receivers are turned on irregularly. Here we are to compensate the power in a given case. I think that you can choose a capacitor and if we turn it on and the current increases, it means that the receiver is capacitive, and when the current decreases, it is inductive. In my opinion, we have too little data to define it.

bodzio507 · Answer

This is possible in a three-phase system. You must turn on the wattmeter properly.

Anonymous · Answer

This, I know it. But I take it as more likely that it is a single phase system.

Stanislaw elektryk12 · Answer

It is a single-phase system.

bodzio507 · Answer

Then you have the answer above.

And by the way, what are you compensating for?
The current limitation will be small. You will spend more on a capacitor than you will save on electricity.

Usually the reactive power is compensated to cos (phi) 0.95

POWER CALCULATION whether the receiver is inductive or capacitive

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