Determining %PF for Submersible Motor

It is a submersible motor not a motor conencted to submersible pump?

The power factor of the submersible motors are generally poor (significantly poorer than normal motor). What is the value you got?

Is it VFD controlled?

Any small line diagram of the system?

I'm not sure, because as we known that we can't separate the cable feeder and the motor. the values that we've got, 0.067

We obviously worry about the values, caused the values not represent the %PF motor look likes. If the values represent the PF of cable feeder, it's gonna be true probably. But, about the PF motor's? that's why I asked about how to get the PF submersible motor?

we have ask to HV equipment testing specialist from the doble company, he just said maybe the results were shown the PF of cable feeder only, in the same time we known each other that we can't separate the cable feeder and the motor to make sure one by one for PF caused we can't remove the cable ones.

Kindly regards

Pf = 0.067? that is too bad to be true.

If you are checking the pf at the feeder line, you are getting the total pf of the system.

In this position, divorcing the two (or more) pf may not be exactly possible.

The pf will include the motor + cable+ controller.

Motor typically may have around 0.8 pf at full load, and will vary quite widely based on loading (as is usual with any Ind Motors)

The cables may be quite capacitive due to the conductors all around it (earth/water)

Drive (controller) will have its own pf.

yes, that the value we've got the %PF. %PF=0.067,

I will pleasure to share the values scan to you, if you don't mind. Just give me an email address, in order to I can attach the file.

Thank you very much

Julian

Just for future reference, power factor is not shown as a %. It is the ratio of two numbers and is shown as a decimal such a 0.64.

yes, I know

I just wrote . . ." our testing results, the %PF shown value was too low, namely 0.067"

that's all,

But, we curious how to determine the %PF (tan delta test) for the submersible motor which the cable feeder can't removed.

many many thank you, for pay attention

Best Regard

I can't imagine that cable capacitance will make even a measurable difference in PF of the circuit. If anything it will potentially help, so the unrealistic values you are reading have little or nothing to do with the cables.

Something is not right here. Are you sure you don't have your meter stuck on reading peak values? When you first start an AC motor, the PF is nearly 0, just like you are reporting, until the rotor starts to actually turn. If the PF were really 0.067 when running, your current would be nearly 600% of FLC, your Overload protection would be tripping. If your meter is determining PF by sampling the phase angles only in the instant you switch on, but is not updating as the motor spins, you may very well be reading that brief instance in time, maybe 20msec., not the real running values.

no, no, no . . . .

I was talking about the insulation testing. tangen delta test or most known as the doble test (the values shown as %PF), where the %PF is ratio which can explain the dielectric strength of cable,tansformator, and rotating machines still within good range, medium (6 months later re-check necessary) or bad (need to replaced).

So, we are talking about the PdM (Predictive Maintenance), in case we use the tangen delta test to determine and predict the dielectric strength (insulation).

And, I rather convious how to get true results about the submersible motor which the cable can not replaced.

Kindly regard

Juliansyah

First, when you are testing the motor are you looking at it? and can you describe its physical dimensions? Please give me the name plate details of the motor, HP, voltage, amps.

You wrote you are using 12Kv, why? This leads me to think you have a surface motor connected to a submersible pump.

Cables used in ESP's "Electrical Submersible Pumps" the majority of the time are only rated to 5Kv, sometime you can get cable rated higher, but that is made on special order. So until you tell me other wise, its a surface motor and I guess with a short length of cable from motor to switchgear, therefore the cable would not make a difference

I suggest that you go back to the manufacturer/supplier of the motor and read the spec sheet, you are missing something and unfortunately not passing on vital information to the people in this forum. If you know how to calculate the pf of a motor then forget its application and do the maths.

I think it is not pf we are talking about, it is the tanδ and for that I am not sure one can differentiate between the cable and the motor insulations.

have you tried to disconnect the motor from the cable?, if you are testing the insulation, then using 12Kv will damage the motor windings. If you are testing the cable then you need the correct test equipment. What do you have? continual testing of of cable using high voltage will cause a breakdown of the insulation. Again back to my questions.... are you using a submersible motor and submersible cable... if so what length of submersible cable?

Mr. Brich, firstly I wanna thank you for concern.

Look, I told you, that we have the tan delta tester as M4100 which can injected testing voltage up to 12 kV. That means we didn't do inject 12 kV for our specimen test which has capacity 4.16 kV, for these specimen we used injected voltage max only at 2.5 kV (4.16 kV divided by √3), cause we gonna get test phase to ground leakage.

we use the submersible pump and the submersible motor+submersible cable, also at the sametime.

and the length is approximately 300 metres,...

Thanks to share n once again thanks to concern

To : Guest

Yeach, yeach, . . . .

Thanks GOD, finally you get what I mean. Tangent Delta test, we're talking about. I apology if my statement made you confious, . . .

But, No idea ? ? ?

Thanks anyway

The term "power factor" evidently has two different usages, causing great confusion in this discussion.

The first has to do with the phase difference between the voltage and current wave forms for various types of loads (inductive, resistive, capacitive) in AC circuits. The angle of this phase difference is conventionally designated as φ (Greek letter phi, lower case). The power factor associated with this is cos φ, which might typically be about 0.85, or 85%. (Both terminologies are used, but I agree with the other post in preferring the fraction 0.85.) Generators are often rated to handle loads at 0.80 power factor, which is not very favorable but is conservatively realistic in many operating conditions.

The second meaning has to do with power dissipation via leakage currents through the insulation of transformer and motor winding and the conductors between. This relates to tan δ (Greek letter delta, lower case), where ð = 90° - φ. Thus the test for this is called the tan-delta test, also known as the Doble test. I am not very familiar with it, but I understand tan δ < 0.05 is a common acceptance level.

Thus the OP's 0.067 value seems borderline, and apparently he wants to pin it down to the motor versus the cable leakage. This won't be easy without pulling the pump, disconnecting the cable, and testing them separately. Many of the replies have been about the first meaning of power factor, but the OP's question is about the second, where quite different values would be expected.

Further complicating matters, there seems to be a lab testing entity named Doble, which does testing of oils, such as used in some transformers. So not only do we have two meanings of "power factor" to sort out, we also have two meanings of "Doble test." Some name changes would be in order....

Tornado : Thank you, you just make it clearer. explaining the misunderstanding. . . .

Thus, My question is not get answer yet. I just wanna make it easier or a

simple question,

anybody whose know or have got experience to testing the submersible

motor.

especially the dielectric strength (insulation test) as we known as tan delta

test ????? Your immediately reply, obviously appreciated. . .

Thank you for pay attention