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Topic: simple variacs (9 msgs / 322 lines)
1) From: susan oppenheim
hi
I want to put a simplified cheapo variac on my popcorn poppers to slow down
the roasts
can anyone make this how to easy to understand for me
easy enough that i can go into an electronics store with the pumper and
someone there can install it on
thanks
susan oppenheim
java mama toronto

2) From: Jason Brooks
On Win XP Pro, SP2, biblecs 1.5.6, I get this for Psalm 1:
Chapter 1
The Way of the Righteous and the Wicked
No duplications.
HTH,
Jason Brooks
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Jason Brooks
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3) From: Aaron
Susan, el cheapo is probably not the way to go on variacs.  You may 
miser a few pennies on it but if it goes up in smoke after a few roasts, 
what did you really save?
They don't install 'on' to something, it is basically a box that you 
plug your popper into.  It will have a dial or some other type of device 
on it to control the voltage.
One big enough to handle the wattage your popcorn popper is going to put 
out is probably going to weigh 20 pounds at least.
Your best bet is probably to get the one Sweet Maria's offers on their 
web page.  You plug it into the wall, you plug your popper into it you 
turn it on, you turn the knob to adjust the voltage and that's pretty 
much all there is to it.
Aaron

4) From: Jason Brooks
Whoops.  Something odd hit my webmail, or else I'm loosing my mind. 
Please disregard previous.
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5) From: Philip Keleshian
Hi Susan,
As has been stated a popper draws a lot of current so you should have a =
large Variac.  
There are a few more points worth mentioning.
Just reducing the voltage to the popper is not as effective as =
separating the heater from the blower and controlling them separately.
Dropping the voltage to the entire popper will slow the fan which will =
reduce bean agitation and work in the direction to raise the =
temperature. Of course reducing the voltage to the heater will reduce =
the temperature, but you can see what I am getting at.
There are several possible design approaches to popper motors:
1. The first is a 120 volt AC/DC universal motor. This is the method =
used on the original Poppery and the easiest to modify. You can separate =
the motor from the heater and simply control them separately.
2. Second small heater which is used as a dropping resistor for a =
rectifier and low voltage DC motor.  With this approach you can still =
separate the two circuits and control them separately. You will still =
get some heat from the "motor dropping resistor" when you turn down the =
main heater but it will be small.
3. Tap on the main heater to feed the motor rectifier. This offers the =
most challenge. You will need to provide a separate power supply for the =
motor. A transformer feeding the original rectifier is a possible =
approach.
If you separate the heater from the blower you may be able to operate =
the heater on line voltage as you boost the blower to higher speed with =
a small Variac. This will give better been agitation as well as lower =
temperature.
You can ecominise further with the fan control described by Mike =
McCoffee who used to post a lot on this list. He designed a circuit =
where he boosts the line voltage with a small 24 Volt transformer and =
controls it with a lamp dimmer. If you do a Google search for his stuff =
you should be able to find it.
Good luck,
Phil

6) From: Philip Keleshian
This is the same as I posted but with some of the spelling corrected.
Phil

7) From: Scott Marquardt
For poppers, boost for fan is essential if you split the circuit -- so
either Variac or stepup xformer and an expensive high-power dimmer (or a
lower powered one with modded heat sinks).
If you can vary the heater with a potent variac or dimmer, that'd be
valuable as heck.
On 5/5/06, Philip Keleshian  wrote:
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Scott

8) From: Michael Dhabolt
This variac:http://tinyurl.com/797xcCan usually be had on EBay relatively inexpensively.  The Poppery 1
and the Pumper fans both pull slightly more than one Amp when boosted
to the ~=138 Volts that this variac will provide.  They make variacs
with this frame (aprox. 3" diameter) in several current ratings, all
of which are large enough for the poppers fan.
Mike (just plain)

9) From: raymanowen
Susan J.M.T.-
More info please:
What popper/ watts are you using-
What quantity of beans do you presently roast-
What is the voltage at the poppers (do you have a meter?)-
What are the results of your roasting-
What results do you desire?
One positive way to retard the roast in a popper is to use an adequately
heavy extension cord of 15 or 50 feet length. Homer's Despot, Lowe's,
hardware store or what do you already have?
Anything to reduce the voltage to the popper will slow down its roasting
rate. While the heat and the blower speed are both reduced, the blower moto=
r
speed is almost directly proportional to the voltage. The heat power is
proportional to V squared, so it loses heat faster than the blower slows
down.
You may not need a Variac- try the extension cord first. Cheaper and
lighter, if it gives satisfactory results, you're way ahead and you can use
it for anything you want, other times than roasting.
Cheers -RayO, aka Opa!
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