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Main
Date: 24 Oct 2006 23:43:36
From:
Subject: Variac for home coffee roaster
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Does anyone know where I can get an inexpensive variac wholesale? I'd
like to sell some but I can only seem to find websites that are
retailing them...not a manufacturer website. From what I gather, one of
the manufacturers is KRM (http://www.ineedcoffee.com/03/variac/) but I
can't seem to find any traces of them on Google. I'd like one that
retails in the range of around $100 - but the ones on variac.com sell
for wayyyy more.
Any ideas?
Thanks,
Casey
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Date: 25 Oct 2006 08:46:42
From:
Subject: Re: Variac for home coffee roaster
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caseyalgo@gmail.com wrote:
> Does anyone know where I can get an inexpensive variac wholesale? I'd
> like to sell some but I can only seem to find websites that are
> retailing them...not a manufacturer website. From what I gather, one of
> the manufacturers is KRM (http://www.ineedcoffee.com/03/variac/) but I
> can't seem to find any traces of them on Google. I'd like one that
> retails in the range of around $100 - but the ones on variac.com sell
> for wayyyy more.
>
> Any ideas?
>
> Thanks,
> Casey
If you don't want any fancy stuff like a case, knob, outlet, power cord
or meter sometimes you can find them cheap when theaters upgrade. They
used to used them to control stage lights and would gang them together
to get several to run off of the same crank or servo.
Matthew
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Date: 25 Oct 2006 08:42:14
From: tjnamtiw
Subject: Re: Variac for home coffee roaster
|
Go to www.mcmastercarr.com. Search for variac. They are not cheap. If you
have any electronics in your roaster, you can't vary the voltage or you will
wreck it.
Tom
<caseyalgo@gmail.com > wrote in message
news:1161758616.410061.286270@e3g2000cwe.googlegroups.com...
> Does anyone know where I can get an inexpensive variac wholesale? I'd
> like to sell some but I can only seem to find websites that are
> retailing them...not a manufacturer website. From what I gather, one of
> the manufacturers is KRM (http://www.ineedcoffee.com/03/variac/) but I
> can't seem to find any traces of them on Google. I'd like one that
> retails in the range of around $100 - but the ones on variac.com sell
> for wayyyy more.
>
> Any ideas?
>
> Thanks,
> Casey
>
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Date: 25 Oct 2006 06:56:42
From: jim schulman
Subject: Re: Variac for home coffee roaster
|
On 24 2006 23:43:36 -0700, caseyalgo@gmail.com wrote:
>Does anyone know where I can get an inexpensive variac wholesale?
The cheapest are on ebay, you're looking for 1500 volt-amps (1.5 KVA);
although 500 will do for short roasts if you rest it between roasts
and overfuse it. Otherwise,
http://www.sweetmarias.com/prod.roastkits.shtml for $115
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Date: 25 Oct 2006 20:25:43
From: LF
Subject: Re: Variac for home coffee roaster
|
jim schulman wrote:
> On 24 2006 23:43:36 -0700, caseyalgo@gmail.com wrote:
>
> >Does anyone know where I can get an inexpensive variac wholesale?
>
> The cheapest are on ebay, you're looking for 1500 volt-amps (1.5 KVA);
> although 500 will do for short roasts if you rest it between roasts
> and overfuse it. Otherwise,
> http://www.sweetmarias.com/prod.roastkits.shtml for $115
Jim,
A Froogle search turned up a 500 Volt variac, for a good price. I
hooked it up to my iRoast, and quickly blew the 5 Amp fuse.
I now regulate the temperature of the iRoast by covering one of the
exhausts screens on top to warm things up; uncovering the exhaust and
opening the lid a crack to cool things down. Roasts have improved. But
chaff finds its way out during the cooling period.
Now that it's getting cooler outdoors, it's time for indoor roasting
again. I'd like to try the Variac. Any idea how much I can overfuse
it?
Thanks,
Larry
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Date: 26 Oct 2006 00:02:33
From: Craig Andrews
Subject: Re: Variac for home coffee roaster
|
"LF" <fieman@gmail.com > wrote in message
news:1161833143.134548.26310@i3g2000cwc.googlegroups.com...
>
> jim schulman wrote:
>> On 24 2006 23:43:36 -0700, caseyalgo@gmail.com wrote:
>>
>> >Does anyone know where I can get an inexpensive variac wholesale?
>>
>> The cheapest are on ebay, you're looking for 1500 volt-amps (1.5
>> KVA);
>> although 500 will do for short roasts if you rest it between roasts
>> and overfuse it. Otherwise,
>> http://www.sweetmarias.com/prod.roastkits.shtml for $115
>
> Jim,
> A Froogle search turned up a 500 Volt variac, for a good price. I
> hooked it up to my iRoast, and quickly blew the 5 Amp fuse.
>
> I now regulate the temperature of the iRoast by covering one of the
> exhausts screens on top to warm things up; uncovering the exhaust and
> opening the lid a crack to cool things down. Roasts have improved. But
> chaff finds its way out during the cooling period.
>
> Now that it's getting cooler outdoors, it's time for indoor roasting
> again. I'd like to try the Variac. Any idea how much I can overfuse
> it?
>
> Thanks,
> Larry
>
I've posted information about info directly from the manufacturer's
owners manual I think it was Superior variac that showed their variac
can be duty cycled 100% & more!, overrated here & the CG forums.
Coffeebeancorral sells their Chinese variac 500V 5A model with a 10A
fuse in it.
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Date: 26 Oct 2006 00:10:38
From: Craig Andrews
Subject: Re: Variac for home coffee roaster
|
"Craig Andrews" <alt.coffee@deletethis.rogers.com > wrote in message
news:4qaqanFm8ftnU1@individual.net...
>
> "LF" <fieman@gmail.com> wrote in message
> news:1161833143.134548.26310@i3g2000cwc.googlegroups.com...
>>
>> jim schulman wrote:
>>> On 24 2006 23:43:36 -0700, caseyalgo@gmail.com wrote:
>>>
>>> >Does anyone know where I can get an inexpensive variac wholesale?
>>>
>>> The cheapest are on ebay, you're looking for 1500 volt-amps (1.5
>>> KVA);
>>> although 500 will do for short roasts if you rest it between roasts
>>> and overfuse it. Otherwise,
>>> http://www.sweetmarias.com/prod.roastkits.shtml for $115
>>
>> Jim,
>> A Froogle search turned up a 500 Volt variac, for a good price. I
>> hooked it up to my iRoast, and quickly blew the 5 Amp fuse.
>>
>> I now regulate the temperature of the iRoast by covering one of the
>> exhausts screens on top to warm things up; uncovering the exhaust and
>> opening the lid a crack to cool things down. Roasts have improved.
>> But
>> chaff finds its way out during the cooling period.
>>
>> Now that it's getting cooler outdoors, it's time for indoor roasting
>> again. I'd like to try the Variac. Any idea how much I can overfuse
>> it?
>>
>> Thanks,
>> Larry
>>
>
> I've posted information about info directly from the manufacturer's
> owners manual I think it was Superior variac that showed their variac
> can be duty cycled 100% & more!, overrated here & the CG forums.
> Coffeebeancorral sells their Chinese variac 500V 5A model with a 10A
> fuse in it.
http://groups.google.com/groups/search?ie=UTF-8&q=Overamping+Variac&qt_s=Search
Craig.
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Date: 26 Oct 2006 00:12:06
From: Craig Andrews
Subject: Re: Variac for home coffee roaster
|
"Craig Andrews" <alt.coffee@deletethis.rogers.com > wrote in message
news:4qaqpsFmee92U1@individual.net...
>
> "Craig Andrews" <alt.coffee@deletethis.rogers.com> wrote in message
> news:4qaqanFm8ftnU1@individual.net...
>>
>> "LF" <fieman@gmail.com> wrote in message
>> news:1161833143.134548.26310@i3g2000cwc.googlegroups.com...
>>>
>>> jim schulman wrote:
>>>> On 24 2006 23:43:36 -0700, caseyalgo@gmail.com wrote:
>>>>
>>>> >Does anyone know where I can get an inexpensive variac wholesale?
>>>>
>>>> The cheapest are on ebay, you're looking for 1500 volt-amps (1.5
>>>> KVA);
>>>> although 500 will do for short roasts if you rest it between roasts
>>>> and overfuse it. Otherwise,
>>>> http://www.sweetmarias.com/prod.roastkits.shtml for $115
>>>
>>> Jim,
>>> A Froogle search turned up a 500 Volt variac, for a good price. I
>>> hooked it up to my iRoast, and quickly blew the 5 Amp fuse.
>>>
>>> I now regulate the temperature of the iRoast by covering one of the
>>> exhausts screens on top to warm things up; uncovering the exhaust
>>> and
>>> opening the lid a crack to cool things down. Roasts have improved.
>>> But
>>> chaff finds its way out during the cooling period.
>>>
>>> Now that it's getting cooler outdoors, it's time for indoor roasting
>>> again. I'd like to try the Variac. Any idea how much I can overfuse
>>> it?
>>>
>>> Thanks,
>>> Larry
>>>
>>
>> I've posted information about info directly from the manufacturer's
>> owners manual I think it was Superior variac that showed their variac
>> can be duty cycled 100% & more!, overrated here & the CG forums.
>> Coffeebeancorral sells their Chinese variac 500V 5A model with a 10A
>> fuse in it.
>
> http://groups.google.com/groups/search?ie=UTF-8&q=Overamping+Variac&qt_s=Search
>
> Craig.
http://groups.google.com/groups/search?q=Overamping+Variac&start=0&ie=UTF-8&filter=0
Craig.
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Date: 26 Oct 2006 03:15:34
From: jim schulman
Subject: Re: Variac for home coffee roaster
|
On 25 2006 20:25:43 -0700, "LF" <fieman@gmail.com > wrote:
>Now that it's getting cooler outdoors, it's time for indoor roasting
>again. I'd like to try the Variac. Any idea how much I can overfuse
>it?
The Iroast is around 1200 watts, so a 10 amp would do it. That being
said -- this one is a horrible candidate for a variac; the internal
temperature cotrols will just make it cycle to low air (for more heat)
the lower you set the variac. The low air setting is hardly enough to
ensure an even roast
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Date: 26 Oct 2006 17:31:10
From: Mike Hartigan
Subject: Re: Variac for home coffee roaster
|
In article <thr0k2dm1kbh0e6klag46hs3s63q7eqgh1@4ax.com >,
jim_schulman@ameritech.net says...
> On 25 2006 20:25:43 -0700, "LF" <fieman@gmail.com> wrote:
>
> >Now that it's getting cooler outdoors, it's time for indoor roasting
> >again. I'd like to try the Variac. Any idea how much I can overfuse
> >it?
>
> The Iroast is around 1200 watts, so a 10 amp would do it. That being
> said -- this one is a horrible candidate for a variac; the internal
> temperature cotrols will just make it cycle to low air (for more heat)
> the lower you set the variac. The low air setting is hardly enough to
> ensure an even roast
The biggest problem with the IRoast, in the context of this
discussion, is that it needs to work harder to compensate for a low
ambient temperature. If the voltage at the outlet is much lower than
120VAC (not that uncommon), it might not be able to get hot enough to
roast the beans. The variac allows you to raise the voltage back up
to where it belongs. Higher than 120VAC is definitely not
recommended, though, since you'll be running the risk of frying the
electronics. In any event, it probably wouldn't result in a higher
roasting temp since, once the programmed temp is reached, the
internal temp controller should keep it from going any higher,
regardless of how high you crank up the voltage.
--
-Mike
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Date: 27 Oct 2006 18:48:22
From: I->Ian
Subject: Re: Variac for home coffee roaster
|
On Thu, 26 2006 17:31:10 -0500, Mike Hartigan
<mike@hartigan.dot.com > wrote:
> Higher than 120VAC is definitely not
>recommended, though, since you'll be running the risk of frying the
>electronics.
If running at higher than 120V fries the electronics, then the iRoar
is a bigger load of [expletive deleted] than denigrated thus far.
Most modern electronics are capable of running well over 120V. Typical
line IC power supplies provide a well regulated output from 85 to
~300VAC, usually downrated to 100 to 240VAC.
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Date: 25 Oct 2006 21:12:08
From: The Other Funk
Subject: Re: Variac for home coffee roaster
|
Finding the keyboard operational
caseyalgo@gmail.com entered:
> Does anyone know where I can get an inexpensive variac wholesale? I'd
> like to sell some but I can only seem to find websites that are
> retailing them...not a manufacturer website. From what I gather, one
> of the manufacturers is KRM (http://www.ineedcoffee.com/03/variac/)
> but I can't seem to find any traces of them on Google. I'd like one
> that retails in the range of around $100 - but the ones on variac.com
> sell for wayyyy more.
>
> Any ideas?
>
> Thanks,
> Casey
After over 30 years on the electronics industy, I have to say that this is
some of the mose dangerous information I have seen. I think that anyone who
reccomends over fusing for any reason is irresponsible at best. The chance
of fire and electroution is just too great.
That being said, if you must try this, make sure you get a variac that is
for the correct frequency and will handle the current. And please either get
one in a case or put it in one rather then have exposed terminals.
Before you move ahead, read:
http://www.nmr.mgh.harvard.edu/~reese/VariacPage/ and remember that any
electronics in your roaster may be damaged. Also do not expect the
electronic temp.to read correctly.
Yes I am trying to talk you and everyone else out of doing this.
Bob
--
--
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com
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Date: 25 Oct 2006 22:29:22
From: jim schulman
Subject: Re: Variac for home coffee roaster
|
On Wed, 25 2006 21:12:08 GMT, "The Other Funk"
<bobbie@moondoggie.com > wrote:
>After over 30 years on the electronics industy, I have to say that this is
>some of the mose dangerous information I have seen. I think that anyone who
>reccomends over fusing for any reason is irresponsible at best. The chance
>of fire and electroution is just too great.
Then don't buy any small household appliances, especially ones with
motors. The rating on variacs is for continuous duty; if you get new
ones from the manufacturer, you'll see the data sheets allow for
higher loads when the load is resistive, and/or the duty cycle is
short.
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Date: 27 Oct 2006 01:03:22
From: The Other Funk
Subject: Re: Variac for home coffee roaster
|
Finding the keyboard operational
jim schulman entered:
> On Wed, 25 2006 21:12:08 GMT, "The Other Funk"
> <bobbie@moondoggie.com> wrote:
>
>> After over 30 years on the electronics industy, I have to say that
>> this is some of the mose dangerous information I have seen. I think
>> that anyone who reccomends over fusing for any reason is
>> irresponsible at best. The chance of fire and electroution is just
>> too great.
>
> Then don't buy any small household appliances, especially ones with
> motors. The rating on variacs is for continuous duty; if you get new
> ones from the manufacturer, you'll see the data sheets allow for
> higher loads when the load is resistive, and/or the duty cycle is
> short.
I am not going to lecture anyone who wants to put a larger fuse in their
Variac, I just want to make it clear that if you do not know what you are
doing, you might get unexpected results.
I am not following your statement about buying appliances, Can you
elaborate?
Bob
--
--
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com
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Date: 27 Oct 2006 01:33:00
From: jim schulman
Subject: Re: Variac for home coffee roaster
|
On Fri, 27 2006 01:03:22 GMT, "The Other Funk"
<bobbie@moondoggie.com > wrote:
>I am not following your statement about buying appliances, Can you
>elaborate?
Motors on home appliances typically will destroy themselves if run
continuously; the identical motor used commercially or induistrially
would be speced for a lower voltage. I'm not sure if the analogy is
totally correct; but I think in both cases, the ability of the device
to tolerate or dissipate heat before the insulation in the coils
breaks down is the key consideration.
The data sheets in variacs typically have a formula or table showing
the volt-amp rating at various duty-cylces. For a short period of use,
e.g. 15 minutes, followed by a recovery of 5 minutes, these units are
usually good up to about 3 times their nominal rating. In addition,
there are upratings if one isn't using them in conjunction with
stopping and starting motors. The units with fuses included usually
have slo-blo varieties so they can suirvive motor starts.
The nominal rating is always for continuous duty and/or frequently
stopping and starting motor loads, and safe for any application. One
**should** stick to this if one doesn't know anything about the unit
or the application (i.e. selling them for all uses). This was not the
case for roasters who up-amped their variacs -- they had the
datasheets and reports showing how to do it safely. Fopr instance, the
500 KVA unit I used at roughly 1200 VA never showed any coil heat up
over long roast sessions (I had a tc on the windings when I started).
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Date: 28 Oct 2006 01:59:22
From: The Other Funk
Subject: Re: Variac for home coffee roaster
|
Finding the keyboard operational
jim schulman entered:
> On Fri, 27 2006 01:03:22 GMT, "The Other Funk"
> <bobbie@moondoggie.com> wrote:
>
>> I am not following your statement about buying appliances, Can you
>> elaborate?
>
> Motors on home appliances typically will destroy themselves if run
> continuously; the identical motor used commercially or induistrially
> would be speced for a lower voltage. I'm not sure if the analogy is
> totally correct; but I think in both cases, the ability of the device
> to tolerate or dissipate heat before the insulation in the coils
> breaks down is the key consideration.
>
> The data sheets in variacs typically have a formula or table showing
> the volt-amp rating at various duty-cylces. For a short period of use,
> e.g. 15 minutes, followed by a recovery of 5 minutes, these units are
> usually good up to about 3 times their nominal rating. In addition,
> there are upratings if one isn't using them in conjunction with
> stopping and starting motors. The units with fuses included usually
> have slo-blo varieties so they can suirvive motor starts.
>
> The nominal rating is always for continuous duty and/or frequently
> stopping and starting motor loads, and safe for any application. One
> **should** stick to this if one doesn't know anything about the unit
> or the application (i.e. selling them for all uses). This was not the
> case for roasters who up-amped their variacs -- they had the
> datasheets and reports showing how to do it safely. Fopr instance, the
> 500 KVA unit I used at roughly 1200 VA never showed any coil heat up
> over long roast sessions (I had a tc on the windings when I started).
Ah! I must have had a brain lockup. Sorry.
For the record, you are correct about duty cycles on motors and variacs. My
concern is more for prople who do not understand them. Add that to
over-fusing and the possibility of substandard household wiring, well the
odds are that nothing bad will happen but the worst could happen.
Another concern is that someone will save money by buying a non-cased
variac. The thought of the exposed terminals just scares me.
I'll be the first to admit that I am a worry-wort. My comment about over
fusing being irresponsible is just that. Me worrying that someone who
doesn't know what they are doing with electricty hurting them self just for
a cup of coffee.
Bob
--
--
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com
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Date: 27 Oct 2006 23:56:06
From: jim schulman
Subject: Re: Variac for home coffee roaster
|
On Sat, 28 2006 01:59:22 GMT, "The Other Funk"
<bobbie@moondoggie.com > wrote:
>I'll be the first to admit that I am a worry-wort. My comment about over
>fusing being irresponsible is just that. Me worrying that someone who
>doesn't know what they are doing with electricty hurting them self just for
>a cup of coffee.
This is a fairly constant argument on alt.coffee, and both sides are
necessary.
-- I'm all for reasonable people trying new things, even if it voids
the warranty. This is what has led to most of the expertise, what
there is of it, accumulated by this group.
-- By reasonable I mean people who are cautious and read up a bit, or
have prior experience. Since we do hear from people who just thought
they were being reasonable on their projects, the warnings are also a
good thing.
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Date: 25 Oct 2006 15:41:02
From:
Subject: Re: Variac for home coffee roaster
|
On Wed, 25 2006 21:12:08 GMT, "The Other Funk"
<bobbie@moondoggie.com > wrote:
>After over 30 years on the electronics industy, I have to say that this is
>some of the mose dangerous information I have seen. I think that anyone who
>reccomends over fusing for any reason is irresponsible at best. The chance
>of fire and electroution is just too great.
I could not agree more. I may have posted a similar opinion here (or
somewhere else, who remembers?). But, where ever it was, I got a slug
of responses from others who were thrilled with their overfused
variacs and a lot of reasons why their houses will not burn down.
Seems someone on the internet is selling them and selling the
hard-to-find fuses-that-fit for precisely this application. There's
always someone on the net ready to turn a quick buck. Haven't heard of
anyone whose house burned down yet.
If I recall Casey's original post, s/he's looking for something in the
$100 retail range. That should be easy. I run one of the red (that's a
color, not a 1960's political statement) Chinese jobs that I paid
about a hundred bucks retail. Has served me well. If anyone really
cares, I can try to find the seller, but a reasonably competent search
should get it done.
_______________________________________
Please Note: If you find a posting or message from me
offensive, inappropriate, or disruptive, please ignore it.
If you don't know how to ignore a posting, complain to
me and I will be only too happy to demonstrate.
|
| |
Date: 25 Oct 2006 11:36:45
From: Omniryx@gmail.com
Subject: Re: Variac for home coffee roaster
|
Try a used electronics parts dealer, if you have one nearby. I was in
one of our local emporiums (emporia?) just a couple of days ago and
they had piles of variacs, from tiny ones up to gigantic,
Frankenstein's-laboratory models. Cheap, too.
Will
MattClem@gmail.com wrote:
> caseyalgo@gmail.com wrote:
> > Does anyone know where I can get an inexpensive variac wholesale? I'd
> > like to sell some but I can only seem to find websites that are
> > retailing them...not a manufacturer website. From what I gather, one of
> > the manufacturers is KRM (http://www.ineedcoffee.com/03/variac/) but I
> > can't seem to find any traces of them on Google. I'd like one that
> > retails in the range of around $100 - but the ones on variac.com sell
> > for wayyyy more.
> >
> > Any ideas?
> >
> > Thanks,
> > Casey
>
> I got mine on ebay for $22, shipping was $25 (those things are heavy)
>
> Mine did not include an outlet or fuse but I found clear instructions
> on www.nmr.mgh.harvard.edu/~reese/VariacPage/
>
> Have fun...
>
> Matt
|
| |
Date: 25 Oct 2006 10:21:30
From:
Subject: Re: Variac for home coffee roaster
|
caseyalgo@gmail.com wrote:
> Does anyone know where I can get an inexpensive variac wholesale? I'd
> like to sell some but I can only seem to find websites that are
> retailing them...not a manufacturer website. From what I gather, one of
> the manufacturers is KRM (http://www.ineedcoffee.com/03/variac/) but I
> can't seem to find any traces of them on Google. I'd like one that
> retails in the range of around $100 - but the ones on variac.com sell
> for wayyyy more.
>
> Any ideas?
>
> Thanks,
> Casey
I got mine on ebay for $22, shipping was $25 (those things are heavy)
Mine did not include an outlet or fuse but I found clear instructions
on www.nmr.mgh.harvard.edu/~reese/VariacPage/
Have fun...
Matt
|
| | |
Date: 25 Oct 2006 15:31:48
From:
Subject: Re: Variac for home coffee roaster
|
Errr, folks: Casey is looking for WHOLESALE suppliers of variacs. All
these great recommendations for cheapo sources for A variac are good
information for others, but Casey probably isn't looking for one or
two hot deals.
I cannot help but the Source for variacs these days is no secret:
CHINA.. You'll need to look for someone with China connections. Have
you tried your query to the on-line electronics retailers. Depending
on how many you need, I'm guessing these guys -- who do have the China
connections -- can cut you a deal.
>
>caseyalgo@gmail.com wrote:
>> Does anyone know where I can get an inexpensive variac wholesale? I'd
>> like to sell some but I can only seem to find websites that are
>> retailing them...not a manufacturer website. From what I gather, one of
>> the manufacturers is KRM (http://www.ineedcoffee.com/03/variac/) but I
>> can't seem to find any traces of them on Google. I'd like one that
>> retails in the range of around $100 - but the ones on variac.com sell
>> for wayyyy more.
>>
>> Any ideas?
>>
>> Thanks,
>> Casey
_______________________________________
Please Note: If you find a posting or message from me
offensive, inappropriate, or disruptive, please ignore it.
If you don't know how to ignore a posting, complain to
me and I will be only too happy to demonstrate.
|
| |
Date: 26 Oct 2006 01:12:01
From: daveb
Subject: Selling Variacs? why?
|
WHY! would anyone want to peddle variacs?
Heavy,
imported,
high shipping costs
high liability issues,
lots of chances of misuse, abuse
EXPENSIVE returns
plenty of competion already
etc etc.
If you are looking to make a real profit -- sell something like ladie's
lingerie!
Light, cheap, non-returnable, [usually] will not catch fire!
Dave
136 - 0 returns
www.hitechespresso.com
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| | |
Date: 27 Oct 2006 01:42:07
From: The Other Funk
Subject: Re: Selling Variacs? why?
|
Finding the keyboard operational
daveb entered:
> WHY! would anyone want to peddle variacs?
>
> Heavy,
> imported,
> high shipping costs
> high liability issues,
> lots of chances of misuse, abuse
> EXPENSIVE returns
> plenty of competion already
> etc etc.
>
> If you are looking to make a real profit -- sell something like
> ladie's lingerie!
>
> Light, cheap, non-returnable, [usually] will not catch fire!
>
> Dave
> 136 - 0 returns
> www.hitechespresso.com
Variac is a trademark of General Radio BTW. Like Band-Aid, Xerox, and
Kleenex. The generic name is autotransformer.
There are a lot of need to control voltage sensitive devices wich is what a
Variac does. Consumer appliances are not as voltage sensitive as most people
think they are. In the US, the requirement is +/- 10 %. In other words for a
nominal 120 VAC, anything between 108 and 132 is OK.
Lingerie has the whole size issue.
Bob
--
--
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com
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Date: 26 Oct 2006 20:00:45
From: LF
Subject: Re: Variac for home coffee roaster
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Mike Hartigan wrote:
once the programmed temp is reached, the
> internal temp controller should keep it from going any higher,
> regardless of how high you crank up the voltage.
>
> --
> -Mike,
If I understand you, that has not been my experience with the iRoast.
Bean temperature, as measured by a thermometer probe into the beans
(not touching any metal, about 1/2 inch above the bottom of the
container), can easily go 30F above the programed temperature. I think
the internal temp controller sits in the center of the iRoast, above
the heater coils-- in the path of the hot air being blown into the
beans. IMO, one of the iRoasts big problems is that you have no way of
knowing what the bean temp is without inserting a thermometer into the
beans. The second big problem is that you can not adjust temperature
on the fly. The "roasting program" is just a wild guess. The
measured temperature from the iRoast gives inconsistent results --
sometimes lower than bean temp, sometimes highter. It reminds me of a
broken clock -- tells the correct time twice a day. The programed
temperature is also inaccurate, and does not even set a ceiling teemp.
I got an Variac in hopes of being able to adjust temp on the fly --
mostly to lower it. From the discussion here, it seems like the
Variac won't help enough. When I lower the temperature the fan will go
too slow, and the beans will get an uneven roast.
All the best,
Larry
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Date: 26 Oct 2006 11:30:33
From: LF
Subject: Re: Variac for home coffee roaster
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jim schulman wrote:
> The Iroast is around 1200 watts, so a 10 amp would do it. That being
> said -- this one is a horrible candidate for a variac; the internal
> temperature cotrols will just make it cycle to low air (for more heat)
> the lower you set the variac. The low air setting is hardly enough to
> ensure an even roast.
Thanks Jim & Craig.
In that case, probably I should stay with the "regulation of air flow"
method of regulating iRoast temp. I've been thinking of a SC/CO
project. I'd like better control over bean temp during roasting and to
be able to roast a larger amount of beans than the iRoast allows.
All the best,
Larry
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Date: 27 Oct 2006 05:41:42
From: Omniryx@gmail.com
Subject: Re: Variac for home coffee roaster
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jim schulman wrote:
Fopr instance, the
> 500 KVA unit I used at roughly 1200 VA never showed any coil heat up
> over long roast sessions (I had a tc on the windings when I started).
Ummmmm....considering that a 500KVA autotransformer has a current
capacity of about 1200 amps at 240 volts, I daresay it didn't heat up,
Jimbo. But since a 500KVA A/T typically weighs something in excess of
600 kg and requires 3-phase power, mightn't it be just a tiny bit of
overkill for your typical home roaster?
Will (who wonders if Jim powers the sociology department with his
autotransformer when not roasting beans)
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Date: 27 Oct 2006 01:25:22
From: daveb
Subject: Re: Variac for home coffee roaster
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500 VA
[ a 500 KVA is the size of a volkswagen ]
:)
dave
137
jim schulman wrote:
> On Fri, 27 2006 01:03:22 GMT, "The Other Funk"
> <bobbie@moondoggie.com> wrote:
>
> >I am not following your statement about buying appliances, Can you
> >elaborate?
>
> Motors on home appliances typically will destroy themselves if run
> continuously; the identical motor used commercially or induistrially
> would be speced for a lower voltage. I'm not sure if the analogy is
> totally correct; but I think in both cases, the ability of the device
> to tolerate or dissipate heat before the insulation in the coils
> breaks down is the key consideration.
>
> The data sheets in variacs typically have a formula or table showing
> the volt-amp rating at various duty-cylces. For a short period of use,
> e.g. 15 minutes, followed by a recovery of 5 minutes, these units are
> usually good up to about 3 times their nominal rating. In addition,
> there are upratings if one isn't using them in conjunction with
> stopping and starting motors. The units with fuses included usually
> have slo-blo varieties so they can suirvive motor starts.
>
> The nominal rating is always for continuous duty and/or frequently
> stopping and starting motor loads, and safe for any application. One
> **should** stick to this if one doesn't know anything about the unit
> or the application (i.e. selling them for all uses). This was not the
> case for roasters who up-amped their variacs -- they had the
> datasheets and reports showing how to do it safely. Fopr instance, the
> 500 KVA unit I used at roughly 1200 VA never showed any coil heat up
> over long roast sessions (I had a tc on the windings when I started).
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Date: 27 Oct 2006 11:19:11
From:
Subject: Re: Variac for home coffee roaster
|
LF wrote:
> Mike Hartigan wrote:
> once the programmed temp is reached, the
> > internal temp controller should keep it from going any higher,
> > regardless of how high you crank up the voltage.
> >
> > --
> > -Mike,
> If I understand you, that has not been my experience with the iRoast.
> Bean temperature, as measured by a thermometer probe into the beans
> (not touching any metal, about 1/2 inch above the bottom of the
> container), can easily go 30F above the programed temperature. I think
> the internal temp controller sits in the center of the iRoast, above
> the heater coils-- in the path of the hot air being blown into the
> beans. IMO, one of the iRoasts big problems is that you have no way of
> knowing what the bean temp is without inserting a thermometer into the
> beans. The second big problem is that you can not adjust temperature
> on the fly. The "roasting program" is just a wild guess. The
> measured temperature from the iRoast gives inconsistent results --
> sometimes lower than bean temp, sometimes highter. It reminds me of a
> broken clock -- tells the correct time twice a day. The programed
> temperature is also inaccurate, and does not even set a ceiling teemp.
>
> I got an Variac in hopes of being able to adjust temp on the fly --
> mostly to lower it. From the discussion here, it seems like the
> Variac won't help enough. When I lower the temperature the fan will go
> too slow, and the beans will get an uneven roast.
Larry,
My comments were not intended to suggest that the IRoast was accurate
in its control or display of the roasting temperature, or that it was
an ideal design. I'm simply suggesting that it would be expected to
limit the temp on the high side to whatever it was going to limit it to
regardless of the line voltage (within limits, of course). If you
boost the voltage, it would achieve that temp sooner, and the
controller would prevent it from going any higher. Lowering the temp,
as you correctly observed, is equally futile, albeit for a different,
though not unrelated reason. The only thing that a variac will buy you
with an IRoast is the ability to correct for a low (or high) voltage
condition at the outlet, presumably removing one of the causes of roast
inconsistency. It's not nearly as useful as it is with, say, a Cafe
Rosto (which I routinely controlled on the fly with a variac). Your
comments regarding the displayed vs programmed vs actual temps are
irrelevant to this discussion. Controlling the voltage using a variac
will not increase their accuracy, nor will it decrease it.
-Mike
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