New/Old powerstat bench variac. :D

[Igotitbad]

A friend of mine that works for a local electronic shop has updated a few things and didn't require this powerstat anymore and he asked me if I wanted it so here it is, at this time I have checked all electromechanical parts on both sections this includes the wiper contact brush and cleaned and lubricated the top of the variac electrical wiper contact.

These work extremely well and both sections have smooth voltage adjustment from 0v-120v plus I can go dual phase upto 240v per phase on this big heavy bad boy depending how I configure it! You can set it up for 120v@30AMPS! Single Phase or 240v/480v @ 15AMPS! dual phase. Upto 7.5kw
"Holy Bat Droppings Batman!!"

Downside: is each section weighs in at over 20lbs
Upside: this is now going to be my new benchtop I mean "Floor lol" with casters Variac

Lol the knob is as big as a softball!


Just wanted to share with everyone

 

[Tom Bavis]

Hard to imagine needing the full capacity of this - half should be plenty. Looks like you could wire it for 120V in, 0-280V out as well, if you have some 240V equipment. Used variacs like that in a communications shop, for international customers. And had a triple stack of 30A variacs for 3-phase equipment.

 

[Igotitbad]

Hard to imagine needing the full capacity of this - half should be plenty. Looks like you could wire it for 120V in, 0-280V out as well, if you have some 240V equipment. Used variacs like that in a communications shop, for international customers. And had a triple stack of 30A variacs for 3-phase equipment.

Yes its definitely way over board for tube amp repair but it looks really cool in my electronics shop for testing and works quite well I mite add. This variac will also be used in several other high voltage/power applications in my shop including lasers of all types, like gas and solid state lasers low voltage/high voltage pulsed power systems, railguns and maybe a giant "PPP vacuum tube tesla coil"
just for fun. >

 

[gadget73]

I think mine is a 7.5 amp and I've never used it's capability. Have it because the price was right.

 

[Igotitbad]

Hard to imagine needing the full capacity of this - half should be plenty. Looks like you could wire it for 120V in, 0-280V out as well, if you have some 240V equipment. Used variacs like that in a communications shop, for international customers. And had a triple stack of 30A variacs for 3-phase equipment.

I also have a tripple stack variac of the same voltage but they are only 9.5 amps I believe, they had experienced a electrical short on two of the sections and have damaged contact surface's "melted wire" and could not be saved, although I could repair the damage to the wire and use them as fixed voltage outputs for "110v-115v-117v-120". Or..or..? so many different purposes I could use these for.

In the pic the good one still has the knob.

 

[Tom Bavis]

Save the parts at least - when a Variac brush wears out, it isn't easy to find replacements.

 

[Igotitbad]

You can find the brushess for 100 dollers plus online if you look around, I found the manuals for each set of variacs and so I do have the part numbers for the brushess.
Two of the brushes have gone through a catastrophic short and exploded "one is still good though" so this one is going to be put together in nice metal case and put to use in my shop, the other two I could modify for whatever project I'm into at the moment.. like
I could rewind with two coil's on one and make a giant cmc filter choke for my audio front end using it with a line balancing transformer to construct a "Balanced Power Conditioner.." just an idea..
I designed and built one before in my 20's for my recording studio and what it dose is reduce the total system noise floor by removing all line interference like any noise or AC humm, it makes your audio equipment sound like a black hole until instruments or music are played through it!

Grounding is the most important part of building this.
Also just want to point out if you build one of these for yourself be careful what you power from it as both of the lead's are hot coming from electrical output @ 60v-0v-60v giving you 120v of balanced conditioned power. I reserved and only used this on analoge equipment for this reason as most SMPS power supplies won't really benefit from this type of power conditioning.

 

[Igotitbad]

As you can see from the picture the contact brush literally exploded from a electrical short!

I plan on milling these old carbon brushess out and rebrazing/solder them with some new high density copper impregnated carbon graphite brush material to rebuild them, its not hard to do and saves me $100.00 If I have to replace the brush on the good variac in the future.

I do have 2 so I will never need new brushess for this variac

 

[Igotitbad]

Here is a couple of pics of the damage that was done to both variac sections as a result from the electrical short.

 

[Igotitbad]

Hard to imagine needing the full capacity of this - half should be plenty. Looks like you could wire it for 120V in, 0-280V out as well, if you have some 240V equipment. Used variacs like that in a communications shop, for international customers. And had a triple stack of 30A variacs for 3-phase equipment.

The highest voltage I could get reconfiguring wiring was 210v out with 120v in do you have any idea how to wire to get 280v? this would be useful to me as I work with all types of equipment with differering voltages.

No practical equipment could utilize this much power but a 5kw-10kw tesla coil could easily enjoy this variac for power consumption. Im a little unpractical by nature so this kinda tool in my eyes is completely necessary for mad science experimentation of all sorts, I guess there's some practical applications too! I suppose..

I have uploaded the pdf for the powerstat 226v2 if you would like to look at it. Best I can determine in wiring in the fashion you discribe is called boost connection mode from the connection diagram?

 

[gadget73]

i always wire mine for 0-100% output, prevents mistakes from happening.

Looks like for 120 in and 0-280 out, you use diagram #2. Input on 1 and 6, output from 1 to 3.

 

[Igotitbad]

i always wire mine for 0-100% output, prevents mistakes from happening.

Looks like for 120 in and 0-280 out, you use diagram #2. Input on 1 and 6, output from 1 to 3.

Thank you for looking! I thought I had already done this wiring schem humm...Imisunderstood the diagram and didn't correctly connect for 280.. Im getting 285 now, thank you gadgit for your time.

But for now im like you and have it wired for 0-120 for exactly the same reason, Its the wiser thing to do right for any normal application that is.

 

[Tom Bavis]

Add a digital voltmeter, 0-300V if you're using the "step-up" connection. A few bucks from Amazon or eBay or MPJ: https://www.mpja.com/Digital-Panel-Meters/products/52/

 

[Igotitbad]

I have several of them that are good to 500v
I build a lot of high voltage projects so I definitely have some in stock, they are dual display volts/amps meters and perfect for the powerstats that I have, there are three that work in total, I may only keep two and sell one.. two is good enough for my lab. One of the big ones for the benchtop and one of the small ones just for portability for goodness sakes.

 

[Igotitbad]

I think mine is a 7.5 amp and I've never used it's capability. Have it because the price was right.

Heck yeah mine was $free.99 and these are not cheap.. a friend of mine in Vegas gave me these two set's I was floored to see what they are actually worth and most likely reason I never bought a variac with anywhere near the capabilities of this beast.