Questions about a "Variac" I just purchased.

[Mr.Peaberry]

I just purchased a 'Variac' on Craigslist. It's actually a Staco brand if that matters. I picked it up last night, and as I was getting ready to take pictures of it to post here, I noticed it was NOT a 12amp model as the seller had indicated, but rather a 10amp model with a 12amp fuse. As I am unfamiliar with the range of use for these items, I had been looking for something with a great deal more range...like 20amp...than needed for my 1300watt turbo oven build. This is interesting though as I see that the output can be 140v or 120v.

My question is this, can I use this unit on the 140V setting, or will that destroy my turbo oven, variac, or both? If I use it on the 120v setting, then I will max out at 1200watts at 100%....which may be okay, as a lot of these turbo ovens builds I've seen have used 1200watt heating coils successfully. The variac was listed at $50, but the guy let it go for $40.00, so I feel that he just didn't know enough to accurately describe it as a 10amp unit...even though it's printed under the control knob on the unit under "Output"...lol! If it becomes the issue for poor outcomes with my roasts, then I will look for another, and use this for controlling the fan, or agitator motor.

I will upload images from home. I can't access an image resizer from work....

Peaberry

 

[BoldJava]

...
My question is this, can I use this unit on the 140V setting...

No. Get a Kill A Watt and measure your voltage at the outlet. On my Gene Cafe, I can roast effectively at 119.5V using the Staco (mine is 20A). If you push it about 123-124V, I believe you are looking to damage all your controls as well as running a safety issue. I am anything but an electrician so take that with a grain of salt. I just wouldn't do it.

 

[Mr.Peaberry]

Thanks Dave. I too am anything but an electrician, but I can do basic house wiring and such. I wasn't having any success testing the Staco, so I popped the fuse out and discovered that the fuse was not only blown...someone had been using a 20amp fuse!! Maybe that's why the guy sold it, lol. It probably kept tripping his 15amp circuit breaker. Don't know what he did to blow the 20amp fuse though. I hooked up a little motor I bought a couple months ago when I started this project, and it runs on both 120 & 140 volts...just faster on the 140. I'm going to ask on another forum about running a turbo oven heating element at the 140 setting. I will have disconnected the build in thermostat control anyhow, so the Staco is going to be the only thing controlling the power to the heating element. I think it should be fine, but I'm totally with you, I want someone who knows what the heck they're doing to confirm before I blow out the turbo oven!! Thanks for your input!

Cheers,

Peaberry

 

[BoldJava]

... I'm going to ask on another forum about running a turbo oven heating element at the 140 setting. ..

Señor PB,

Use Home. A bud runs the forum, he is an EE. Larry, milowebailey.

 

[Mr.Peaberry]

Very cool....thanks mi amigo! I'll definitely contact Larry. Strange that they are in Seattle...lol!