Variacs

[rasqual]

I only use a Variac to control the blower in my popper, driving the heat with whatever the wall delivers. That means I don't need a high current rating for it.

This allows me to practically max out my starting beans at 10 oz, and roast anywhere between 8 and 14 minutes, as desired. It's nice to be able to do a roasted 8.5 oz. or so.

Wish I had the thing PID'd already.

[BoldJava]

Houston, we have no problem.  Variac has landed.

B|Volts

[peter]

Aaahh... you sold out man.  For years, the little guy's been down-trodden by the Man, keeping us beaten down with low-voltage and substandard service.  You had a chance to really stick it to the Man, but you sold out and bought a Variac.  You gotta keep on with the struggle man.  Don't let the Man get away with it.  Do it for all the homeroasters in the 'hood, man.

[BoldJava]

Aaahh... you sold out man...

This has nothing to do with selling out and everything to do with Toyz.  Here's my accounting:

(-1)  You busted that ugly, WWII press pot
(+1)  I bought the 22 oz Yama stove top
(+1)  I bought the 20V variac

By my reckoning, that is a net gain of 3 toys.  Getting constant voltage is a throw in.

B|Java

[headchange4u]

Looks like I'm gonna have to look into picking up a Variac, especially after seeing rasqual's website where he uses it combined with a popcorn popper to get some 14 minutes roasts. My Poppery I is HOT and sometimes I'm lucky to make it 5 minutes before I have to dump the beans on a city+/full city roast. I like the flavor longer roast imparts in the beans. I can stretch my Poppery II out to 6 or 7 minutes, but it would be nice to be able to go longer.

Would a Variac be beneficial to a SC/TO setup since most times they are on the same circuit and/or outlet?

[peter]

Would a Variac be beneficial to a SC/TO setup since most times they are on the same circuit and/or outlet?

I think you'd want to split the wiring, leaving the fan stock, and only using the variac on the heating element.

[rasqual]

Would a Variac be beneficial to a SC/TO setup since most times they are on the same circuit and/or outlet?

I think you'd want to split the wiring, leaving the fan stock, and only using the variac on the heating element.

It's easier on the blower, but that works better with a boost to 140, which my under-powered Variac can do. I didn't realize the high power ones only went to 130.

If you boost the blower instead of the heater coil, you get the benefit of being able to do bigger batches!

I regularly do 10 oz.

[BoldJava]

It's easier on the blower, but that works better with a boost to 140, which my under-powered Variac can do. I didn't realize the high power ones only went to 130....

My model (20A) maxes out at "130" on the dial.  That is not volts.  I calibrated via the Kill A Watt and a setting of 113 on the dial gave me 120v on the Kill A Watt.

>>>Thanks to the Homeroast list for this correction: these are rated 0-130v output @ 110v input so if you have normal 120v input you'll get 0 to 141v output with this Variac....>>>

http://www.sweetmarias.com/prod.obsolete.shtml

B|Java

[rasqual]

Whoa!

Here's one that'll go to 150 VAC. Never seen one of these before.

Here's one that's closer to my units specs.

DANG. This would have been a great deal. "As many transformers as you want" -- Buy it now price of $13? Aaargh!

[peter]

Would a Variac be beneficial to a SC/TO setup since most times they are on the same circuit and/or outlet?

I think you'd want to split the wiring, leaving the fan stock, and only using the variac on the heating element.

It's easier on the blower, but that works better with a boost to 140, which my under-powered Variac can do. I didn't realize the high power ones only went to 130.

If you boost the blower instead of the heater coil, you get the benefit of being able to do bigger batches!

I regularly do 10 oz.

Rasqual...  I didn't think you roasted w/ a SC/TO...   

I calibrated via the Kill A Watt and a setting of 113 on the dial gave me 120v on the Kill A Watt.

B|Java...  the thought came to me today, how funny it would be if your Kill A Watt was a defective unit, and has been running 7V low this whole time.   

[kelppaddy]

Whoa!

Here's one that'll go to 150 VAC. Never seen one of these before.

Here's one that's closer to my units specs.

DANG. This would have been a great deal. "As many transformers as you want" -- Buy it now price of $13? Aaargh!

The last two are pretty low in the amperage department and wouldn't be too good for using on heating elements.

kelppaddy

[rasqual]

If you boost the blower instead of the heater coil, you get the benefit of being able to do bigger batches!

I regularly do 10 oz.

Rasqual...  I didn't think you roasted w/ a SC/TO...   

No, popper.

The last two are pretty low in the amperage department and wouldn't be too good for using on heating elements.

True dat. Just for controlling loft (which controls temp wonderfully in a popper).

[BoldJava]

B|Java...  the thought came to me today, how funny it would be if your Kill A Watt was a defective unit, and has been running 7V low this whole time.   

I think your humor is around the bend, you warped Deutschman you.

Mr Wisconsin Energy Pole Climber measured my volts with his super duper meter and it matched my $20 Kill A Watt to the tenth of a volt, you smarty pants.

Today, Wisc Energy came out and put a meter on the box to map the "in" voltage.  Of course, for the first time ever, I am reading 121 volts.  I have never seen that many volts in this house.  I guar-on-tee you that they cranked up the juice or did something with externals to get me that number.

B|Java

[rpn]

The last two are pretty low in the amperage department and wouldn't be too good for using on heating elements.

True dat. Just for controlling loft (which controls temp wonderfully in a popper).

Rasqual has played with this stuff far more than me (read your website), but just a small counterpoint.  I am new to the roasting game and was hesitant to spend dollars on a variac.  I'm using a store-branded Toastmaster (internally same as Poppery II) with a 20-something volt DC motor (I think the Pumper has an AC like the Poppery I).  I can control the speed of that motor with a $10 Radio Shack transformer + 600 watt dimmer switch that was household surplus.  If I had a variac I'd be putting it on the heater circuit where the higher wattage would kill a dimmer switch, but I too am finding that controlling air-flow seems to be sufficient input to control the roast.

I ramp my fan speed down over the course of the roast until I hit 430 - 440F, then I crank the fan back up and kill the heater (it's got an on/off rocker switch which came on the popper).  If I do a poor job with the fan control, I can also cut the heater for a few seconds to hold or slightly drop the temperature during roast (had to do this with decaf recently).

Complete (excessive) details available here: http://rpnreviews.blogspot.com/2008/08/roasting-coffee-at-home.html

-Rich

[ButtWhiskers]

If you are only going to reduce voltage (like for a poppery fan), you can use a 15A 'router speed control' from Harbor Freight Tools ($15).