It has been interesting to watch this little exchange on the list. I'm not going to assume that Chris is trying to mislead anyone, but the point here is that he is advertising a 6-gang variac that comes with some other goodies that one may or may not be interested in ("who cares?" was the wording used). If it's a variac stack you are trying to sell, then it's probably prudent to include the specs for the variac rather than the specs of the "who cares" unit which it's a component of. We might be able to make some assumptions about the variac specs- Staco 5011 series auto transformers come with a 50 amp fuse they are for 120v input and rated at 7kVA each. The variac stack isn't fused at 50 Amps, so teslalabor's analysis isn't quite right, but neither is the 75kVA claim made by Chris. If you can provide some physical measurements of the autotransformers or check the top of the stack for a nameplate and provide that info, you might get more success selling this as a variac stack stuck inside of a "who cares" voltage regulator. BTW - Staco has a part number for the variable transformer listed in the user manual for the voltage regulator (033-7581) but this number doesn't match the part number (031-6954) on the drawing for the 6stack wye configured set of 5011's that I looked at, so that may mean it isn't really made up of 5011's or it could be that it's configured a bit differently for this application and given a unique part number. Best of luck with the sale.
Thomas
From: Teslalabor <teslalabor@xxxxxxxxxxx>
To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
Sent: Wednesday, March 30, 2016 10:04 AM
Subject: Re: [TCML] Giant Variac For Sale
75kVA says the makerplate of what? I only can see a photo of the makerplate
of the whole unit, which says it is 75kVA.
Makerplate says 75kVA, 208Volts @ 208Amps, so: 208 Volts * 208/sqrt(3) Amps
* 3 = 75kVA
The variac is fused with 50Amps, you say. That is a maximum power of 18kVA
for the variacs, what makes completely sense to me (maybe even only 9kVA for
each of the 2 stacks). They are only for controlling the main transformer,
and that beast is rated at 75kVA not the little variacs, thats the thing I
am trying to explain to you.
----- Original Message -----
From: "Chris Boden" <cboden@xxxxxxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Wednesday, March 30, 2016 1:50 AM
Subject: Re: [TCML] Giant Variac For Sale
> Each coil of this variac is fused at 50A, what was yours at? The
> makerplate
> says 75kVA, and it's Staco....I believe them.
>
> On Tue, Mar 29, 2016 at 1:08 PM, Teslalabor <teslalabor@xxxxxxxxxxx>
> wrote:
>
>> :-)))) Very funny. Yes, the small potentiometer knob is used to fine-tune
>> the regulation range, with this you only can change the output voltage in
>> a
>> range of lets say 200-216 Volts.
>> I know this because I bought exactly such an unit like yours some years
>> ago for a big pile of money. I also thought "wow, very cool variac..."
>> The end of the story was, that there was only a very small (3-phase)
>> variac with some kVA's inside, which (when I remember corectly)
>> controlled
>> in combination with another (small) 3 phase transformer the VERY big
>> 3-phase load-transformer inside the housing. BTW, please don't ask me,
>> how
>> this works...
>> I could be wrong but I'm pretty sure that your unit works in the same
>> way... At least you should take this into consideration instead of only
>> rely on size-comparisons with another variacs.
>>
>> ----- Original Message ----- From: "Chris Boden"
>> <cboden@xxxxxxxxxxxxxxxx>
>> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>> Sent: Tuesday, March 29, 2016 6:06 PM
>>
>> Subject: Re: [TCML] Giant Variac For Sale
>>
>>
>> The output is adjustable (it's the little knob under the meter) and has a
>>> considerable range. I don't know it's full range as I haven't tested
>>> this
>>> unit. We got them for the stacks, and then leapfrogged past them in our
>>> upgrade cycle in building the new lab. That's why we're selling these.
>>>
>>> The variac, pulled from the cabinet, will actually handle a 75kVA load
>>> just fine. I know this because it's a slightly smaller version of the
>>> one
>>> I
>>> use every day in our High Voltage lab as our main power supply. There
>>> are
>>> dozens, if not hundreds of videos of my demonstrating it's use in front
>>> of
>>> thousands of people. You yourself are welcome to come here and measure
>>> the
>>> output capacity and compare it yourself. Of course I suggest you bring a
>>> NIST traceable, calibrated measurement set. If you wish to do this, I
>>> would
>>> be happy to provide a complete camera crew and live audience to publish
>>> your results if you have any doubt as to the veracity of my claims.
>>>
>>> It's only a voltage regulator if you keep it intact and use it as such.
>>> Anyone interested on here would likely autopsy it for its component
>>> pieces.
>>> The transformer inside, aside from being "damn big" I know nothing
>>> about.
>>> Though it would make one hell of a boat anchor or a great core for a
>>> reactive ballast.
>>>
>>>
>>> On Tue, Mar 29, 2016 at 11:25 AM, Teslalabor <teslalabor@xxxxxxxxxxx>
>>> wrote:
>>>
>>> Okay! I was little bit confused because of the additional "large
>>>> transformer" you mentioned. What I was talking about, are units similar
>>>> to
>>>> yours, used for automatic "voltage stabilisation". They automatically
>>>> adjust line voltage within a range of +/- some percent. These units
>>>> consist
>>>> of small variacs + big transformer, which takes the load.
>>>> But anyway, you should check the namplate carefully. It says INPUT is
>>>> 166-229 Volts and OUTPUT is fixed at 208 / 120 Volts.
>>>> So this means, this unit can NOT regulate Voltage between 0 - 208
>>>> Volts!
>>>> Is stabilizes the Output Voltage @ 208 Volts, whereas Input voltage can
>>>> be
>>>> anything between 166-229 Volts.
>>>> So this is not a 75kVA Variac Mr. Boden...
>>>>
>>>> ----- Original Message ----- From: "Chris Boden" <
>>>> cboden@xxxxxxxxxxxxxxxx>
>>>> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>>>> Sent: Tuesday, March 29, 2016 4:39 PM
>>>> Subject: Re: [TCML] Giant Variac For Sale
>>>>
>>>>
>>>>
>>>> If you check the pics, this is not a small variac. ;) It's a 6-stack
>>>>
>>>>> (triple-double) of the standard big toroids with balancing chokes.
>>>>> It's
>>>>> one
>>>>> size smaller than our 100kVA variac and will certainly handle the
>>>>> load.
>>>>> Check the pics, the stack fills up half of that cabinet.
>>>>>
>>>>> On Tue, Mar 29, 2016 at 3:45 AM, Teslalabor <teslalabor@xxxxxxxxxxx>
>>>>> wrote:
>>>>>
>>>>> Nice! I also had such an big automatic voltage regulator some time
>>>>> ago.
>>>>>
>>>>>> "Problem" is: I don't remember how it works but the variac itself
>>>>>> (which
>>>>>> would be interesting for TC use) is only a relatively small one,
>>>>>> maybe
>>>>>> 10kVA or less. The main power (75kVA in your case) comes from the big
>>>>>> standard 3-phase transformer, which is controlled via the small
>>>>>> variac
>>>>>> +
>>>>>> controll transformer.
>>>>>> Maybe you should add an info to your auction, that this is NOT a
>>>>>> 75kVA
>>>>>> variac, this could lead to some confusion and you could get some
>>>>>> trouble
>>>>>> otherwise :-)
>>>>>>
>>>>>>
>>>>>> ----- Original Message ----- From: "Chris Boden" <
>>>>>> cboden@xxxxxxxxxxxxxxxx>
>>>>>> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>>>>>> Sent: Tuesday, March 29, 2016 1:21 AM
>>>>>> Subject: [TCML] Giant Variac For Sale
>>>>>>
>>>>>>
>>>>>> If anyone is interested in a massive 6-stack variac, we have one for
>>>>>> sale.
>>>>>>
>>>>>> http://www.ebay.com/itm/222067908245
>>>>>>> This happens to also include a solid cabinet with a large
>>>>>>> transformer
>>>>>>> and
>>>>>>> some control circuitry. The unit actually works, but who cares, it's
>>>>>>> a
>>>>>>> giant 6-stack variac :)
>>>>>>>
>>>>>>> And a matching massive switch as well
>>>>>>> http://www.ebay.com/itm/-/322055321777
>>>>>>> --
>>>>>>>
>>>>>>> Chris Boden
>>>>>>> President
>>>>>>> The Geek Group National Science Center
>>>>>>> www.thegeekgroup.org
>>>>>>> We Build Awesome
>>>>>>>
>>>>>>> --
>>>>>>>
>>>>>>>
>>>>>>> This email may contain confidential and privileged material for the
>>>>>>> sole
>>>>>>> use of the intended recipient. Any review or distribution by others
>>>>>>> is
>>>>>>> strictly prohibited. If you are not the intended recipient please
>>>>>>> contact
>>>>>>> the sender and delete all copies.
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>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>>
>>>>> Chris Boden
>>>>> President
>>>>> The Geek Group National Science Center
>>>>> www.thegeekgroup.org
>>>>> We Build Awesome
>>>>>
>>>>> --
>>>>>
>>>>>
>>>>> This email may contain confidential and privileged material for the
>>>>> sole
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>>>>> strictly prohibited. If you are not the intended recipient please
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>>>>
>>>
>>>
>>> --
>>>
>>> Chris Boden
>>> President
>>> The Geek Group National Science Center
>>> www.thegeekgroup.org
>>> We Build Awesome
>>>
>>> --
>>>
>>>
>>> This email may contain confidential and privileged material for the sole
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>>
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>
>
>
> --
>
> Chris Boden
> President
> The Geek Group National Science Center
> www.thegeekgroup.org
> We Build Awesome
>
> --
>
>
> This email may contain confidential and privileged material for the sole
> use of the intended recipient. Any review or distribution by others is
> strictly prohibited. If you are not the intended recipient please contact
> the sender and delete all copies.
>
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