Variac Help/Insight needed - Page 3

#21: Post by **yakster** » February 27th, 2017, 9:41 pm

I wouldn't recommend the light bulb trick for voltages well above 120 V. What does your kill-a-watt read plugged directly into the outlet?

#22: Post by **JavaBuzz** » February 27th, 2017, 9:43 pm

ACV 200 sounds right if you're talking about the setting to select on the multimeter.

I'm no electrician, but you might have a wiring issue (either that outlet or the circuit the outlet is on). Do any other outlets read that high if you plug directly into them (not through the Variac)? Typically the readings would be sitting around 115-125V. Maybe the multimeter is reading higher than it is, but the killawatt reading is high too. Googling 150V brings up sites talking about "open neutral" or "open ground" wiring issues.

#23: Post by **yakster** » February 27th, 2017, 10:21 pm

An outlet tester might help, they make them with or without the button to test the GFIC function of a GFIC outlet.

February 27th, 2017, 11:02 pm

yakster wrote:What does your kill-a-watt read plugged directly into the outlet?

Why didn't I think of that ???

122.9 - 123.1. Just like it outta.
So....something is wrong with the multimeter, right?
I put it right into the same socket and it reads 149.

The autotransformer (see I'm getting my language cleaned up) is probably fine.
The multimeter is probably junk.

More investigating to come soon.
Thanks everyone for chiming in.

#25: Post by **ira** » February 28th, 2017, 2:34 am

What do the meter and the kill-a-watt say the line voltage is? It just looks like the meter might be reading high.

Ira

#26: Post by **yakster** » February 28th, 2017, 2:49 am

Some voltmeters aren't well shielded and can read high around flourescent tubes, radio frequency sources, etc. See if there's anything nearby affecting your meter.

#27: Post by **chimopaul** » February 28th, 2017, 7:41 am

SJM wrote:Nope, we have to live with our mistakes )))
Including the variac ))

But, Moshe, look: I don't think it's the variac after all.
I figured out the multimeter and these readings make sense but don't explain my problem.
I guess it might be the fan itself....duh.... <image>

By the looks of those numbers, it appears that your multimeter is reading the peak voltage rather than RMS. What mulitmeter are you using and on what setting?

February 28th, 2017, 10:52 am

Here is the multimeter and I think you can see in the picture where it's set....200 ACV....

#29: Post by **yakster** » February 28th, 2017, 2:58 pm

Hmm, I could not find in the manual clarification of if it reads RMS or not. I did find a video review that shows that you can easily adjust the DC voltage readout of the meter to "calibrate" it, not sure if this same adjustment affects AC voltage readings but I'd recommend you use a fresh 9 V battery in the meter if you plan to use it and check the readings of some batteries. I'd definitely trust your Kill-a-Watt over this meter.

February 28th, 2017, 5:56 pm

Thanks, Chris.
New batteries coming up.