Checking for watts...or amps...

[mrcaptainbob]

There are two heaters on this waste oil furnace that I'd like to find out their power. Of coarse they run on 120V, but how can I check the amps? I do have a VOM, but I think the the fourth gradient is for milliamps.

[HayZee518]

take 120 volts and multiply the amps or Ma to get watts

[Speedbump]

You'll need an amp meter to wrap around one of the two legs. If they plug into the wall, you would need something like this to read amperage, wattage and voltage: Electrical Collectible: Home

[HayZee518]

if your meter can read 10 amps or less you can insert the meter in series with one element lead to the hot or neutral and read the amps directly. then all you can do is calculate volts times amps for the wattage. a clamp around ammeter is better because there is no hazard of live bare wires. the jaws just clamp around one lead and you read the amps directly off the led readout.

[mrcaptainbob]

Watts...

Oh! So I can connect the mA scale in series? I thought it was for just micro-sized amperage. Which of the scales should I put it on? The larger number or smaller?

[HayZee518]

usually the largest, but if you have a terminal marked 10A the meter will read it directly. that is 10A and the black lead.

[mrcaptainbob]

Amps check...

I almost tried it today, but thought I'd check with you first. The VOM meter has that part described as DC ma. Then there's the continuity, VDC and of coarse, VAC. Still okay to go ahead and use that DCma range?

[HayZee518]

I was leary myself until I tried it, it works

[mrcaptainbob]

Watts?

Okay then. I'll do that tomorrow. Thanks, HayZee....

[mrcaptainbob]

Watts....

Not sure watts going on here. I set the vom to each of the gradients on the DC mA scale and each time it pinned the needle to the left with a pretty violent chatter. I also switched the leads so it read from the red side of the VOM and from the black side of the VOM. Rats. Was hoping I could get an amp read. Oh well, on to something else....

[HayZee518]

ok, then go to home depot or lowes and buy a cheap ideal clamp around. in the clamp around function it will read ac directly.

[mrcaptainbob]

Buggered up vom....

Well, I guess what I did fried something in the VOM. All scales are out of whack. I put it on 50 DCV and it reads a 12v battery at 23v. The only registration that I can count on is continuity. And that's only because the needle moves. No way to dial the registration back, either. Oh, well. Off to Harbor Freight.....

[HayZee518]

I'm really sorry Bob. I checked harbor freight and they have three types of clamp around meters. If you decide to get one, get one with the most functions. since you are on all wierd hours of the day [or night] maybe you can hook up via yahoo chat. my handle there is tjmierzwa35@yahoo.com. Save a lot of time messaging back n forth in the forum

[Speedbump]

I have an idea these motors your trying to test pull more than 10 amps. Did you move the positive probe to the 10 amp hole instead of the mA lead where it was prior. If you didn't, that would have fried it. I use those red meters for stuff I don't have to be precise with and they work pretty well for $2.95 each. I think they are almost $5.00 on sale now.

[HayZee518]

Speedbump - he's trying to test for amps on the oil heaters on the waste oil burner. Then i guess he's going to calculate the wattage of the heaters.