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Powerstat Type 20 Variac
Found the a Powerstat Type 20 variac at Restore so I decided to build a enclosure for it. The variac itself is housed in the big pull box at the centre. The two smaller boxes at the sides are junction boxes for the in and out lines. I installed a combination switch with a red neon indicator light and a single outlet so I can easily plug stuff into the variac. I also installed a 3A fuse to protect the variac from shorts. It was missing the dial so I made my own, this one goes from 0-150v. 
Keywords: Miscellaneous

Powerstat Type 20 Variac

Found the a Powerstat Type 20 variac at Restore so I decided to build a enclosure for it. The variac itself is housed in the big pull box at the centre. The two smaller boxes at the sides are junction boxes for the in and out lines. I installed a combination switch with a red neon indicator light and a single outlet so I can easily plug stuff into the variac. I also installed a 3A fuse to protect the variac from shorts. It was missing the dial so I made my own, this one goes from 0-150v.

DSC02944.JPG CIMG2950.JPG COL_IMG_3384.JPG dam_building.jpg 20210115_135212.jpg
File information
Filename:COL_IMG_3384.JPG
Album name:joe_347V / Misc. Lighting Pics
Keywords:Miscellaneous
Company and Date Manufactured:Powerstat - enclosure by 347v Electric
Model Number:Type 20
Filesize:166 KiB
Date added:Feb 20, 2015
Dimensions:1800 x 1200 pixels
Displayed:486 times
Color Space:sRGB
DateTime Original:2015:02:19 22:53:16
Exposure Bias:0 EV
Exposure Mode:0
Exposure Program:Program
Exposure Time:1/200 sec
FNumber:f/6.3
Flash:Compulsory Flash
Focal length:33 mm
ISO:100
Make:Canon
Model:Canon EOS REBEL T3
URL:http://www.galleryoflights.org/mb/gallery/displayimage.php?pid=18981
Favorites:Add to Favorites

Comment 1 to 13 of 13
Page: 1

streetlight98   [Feb 20, 2015 at 03:37 AM]
Cool! What is this Powerstat device? Is it just a dimmer switch or something more? I see it can go up to 150V which is interesting. I suppose you could test how well your fixtures handle voltage drops with this. Shocked Laughing
joe_347V   [Feb 20, 2015 at 03:42 AM]
Thanks! It's actually a variable transformer so I can test my lamps by slowly ramping up the voltage instead of applying straight 120v. Apparently that's how you're supposed to test older incandescent lamps because the thermal shock from applying straight 120v will kill the filament.

I guess 150v is the overdrive mode lol, even the normally dim 130v incandescents look nice and bright at that setting. Laughing
GEsoftwhite100watts   [Feb 20, 2015 at 03:52 AM]
Not totally sure how to explain it best but it's NOT your typical wall dimmer for the light over the dining room table, that's a TRIAC. Those just chop up the sine wave I believe, whereas these actually vary the voltage (Someone please correct me if I'm wrong about this). I've experimented with a regular Leviton (Or maybe it was Lutron) rotary TRIAC dimmer and things other than the incandescent lamp it's intended for, inter alia CFLS (Yes, really!) a 175w MV yardblaster (That worked surprisingly well actually!) and a 400w CWA MH highbay (That didn't work very well). I found the trick was keeping an incandescent on there as well (So some resistive load still on there) helped my results. Here it is: https://www.youtube.com/watch?v=YIcB3GZXb14
lite_lover   [Feb 20, 2015 at 08:47 AM]
Well done Joe! Cool
streetlight98   [Feb 20, 2015 at 02:50 PM]
Ah I see. Really cool! @ Andy; yeah I think once the lamp has warmed up and ran for a little, a cap-less ballast can be dimmed but if there's a capacitor involved like with CWA, the cap will keep trying to compensate for the drop in voltage so you need a special dimming circuit with another capacitor like what highbays in stores use if they have the special dimming feature.
GEsoftwhite100watts   [Feb 20, 2015 at 06:17 PM]
Yeah even an incandescent wouldn't dim with the CWA. The HX-NPF yardblaster worked surprisingly well though! (Did you get a chance to watch the shaky iPod camera video of it)?
TiCoune66   [Feb 20, 2015 at 07:34 PM]
You should see my variac! It's a beast the size of a small breaker panel xD It was built in 1944 Shocked Typical 1940s look with a backlit voltmeter. The backlight uses a small C7 or S6 bulb. It didn't have a bulb when I brought it home but I had a GE 3W S6 laying around.

I plan to install an E26 socket eventually and use it as a line fuse with a 15A Edison fuse.
GEsoftwhite100watts   [Feb 21, 2015 at 01:48 AM]
Do you have a pic Vince?
joe_347V   [Feb 22, 2015 at 06:53 PM]
@Darren, thanks!
@Vince sounds like a cool variac! I would also like to see a pic of it. Mine is a pretty small 3A model, I think it was built in the 50s or the 60s.
GEsoftwhite100watts   [Feb 22, 2015 at 07:29 PM]
Are Variacs still commonly made/easy to find? Also does anyone know how well they would work on a modified sine wave inverter? (Since those burn up Triac dimmer switches fast)
TiCoune66   [Feb 24, 2015 at 02:29 AM]
I don't have any picture of it at the moment. But I have a nice selection of lamps to show in a close future, I'll include a pic of that variac as well!
GEsoftwhite100watts   [Feb 24, 2015 at 03:23 AM]
I know you moved, do you still have all the stuff you did prior to that? (Stockpiles of 8' slimline lamps, etc).
joe_347V   [Mar 01, 2015 at 03:14 AM]
Ahh cool, looking forward to those pics Vince!

Comment 1 to 13 of 13
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