Question for you electrial guys about a meter

[makemineatwostroke]

My question is a A W Sperry clamp on meter a fair meter to read amp draw.I bought a HF meter and it won't read the same each time and i don't want to pay the bucks a electrial supply charges being this is a one time experiment on induction water heating

[DrivingMissLazy]

My favorite is the John Fluke meter, but one thing you should realize is that you will never get a true reading to calculate actual KW. Due to the inductance in the heating element you will be measuring the total amps and the power factor of the element will affect the total reading.

For example if the power factor of the load is 0.80 lagging, then only 80% of the amps measured will be actual KW.

What you really need is a true KW meter and a true KVA meter.

Unless the heating element is a total resistive load. Then forget everything else I said. LOL

Richard

[makemineatwostroke]

Richard, I priced that meter and no thanks that meter cost way too much for me to experiment with     thanks anyway

[zimtok]

The clamp on meters are fairly accurate.

But you can get different readings due to many things such as the following:
If the voltage is 120 one time and 110 the next you may see an increase in amp draw.
If you have a 5ft wire feeding the device from the power source or a 100ft wire the reading will be different.
Even colder tempratures can effect the amp draw.


If you want better accuracy you need to use an inline amp meter.


.

[Ncbob]

Like Richard, I tend to go with the Fluke 87...but I'll grant you it's an expensive meter. One thing though when thinking about this sort of equipment.  If you have a generator you might wish to have a meter that reads Hz. (frequency) because this will be how you set the speed on your genset...not voltage. Generally speaking set it at 61 Hz, no load, and if everything else is OK...you'll have no problems.

FWIW

Bob

[FloridaCliff]

You will be fine with the Sperry.

If you are doing a comparitive test and if the meter is off, it will be off on both tests the same.

I have compared my very expensive amp clamp with some cheapies and was amazed at some of there performances.

How accurate are your test requirements?

I bought a HF cheapie to take up on towers, If I drop it, I dont feel so bad. 

Cliff

[Melbo]

Radio Shack has a 20 dollar clamp on meter that I use when I need an idea of what is happening

Melbo