Hi Folks,
I've had great success here finding answers to unordinary questions in the past, I figure I would try again.
Over the weekend, I picked up an old Variac at an estate sale. I did a quick test and it works, and is fairly accurate, so I would like to go ahead and make it a little safer by adding a new 3-prong power cord, fuse and new 3 prong female receptacle for the load side.
However, I am having a bit of difficulty trying to source a shallow 3-pronged receptacle. The one currently installed is very shallow. It's only about 1/4"-3/8" deep from the inside of the Variac cover to the end of the receptacle. Everything I am finding is over 1" deep, and I don't think I have the room inside the cover for that. The other issue is that the current plug is round, which are difficult to find. But that is a minor problem, I figure I am going to have to do some modifications anyway.
I've attached a couple of pictures for your review.
I checked Mouser, Digikey and Amazon without success. Does anyone have an idea where I can find a shallow 3 prong receptacle like this? Or should I just stick with the 2 prong and move on?
I've had great success here finding answers to unordinary questions in the past, I figure I would try again.
Over the weekend, I picked up an old Variac at an estate sale. I did a quick test and it works, and is fairly accurate, so I would like to go ahead and make it a little safer by adding a new 3-prong power cord, fuse and new 3 prong female receptacle for the load side.
However, I am having a bit of difficulty trying to source a shallow 3-pronged receptacle. The one currently installed is very shallow. It's only about 1/4"-3/8" deep from the inside of the Variac cover to the end of the receptacle. Everything I am finding is over 1" deep, and I don't think I have the room inside the cover for that. The other issue is that the current plug is round, which are difficult to find. But that is a minor problem, I figure I am going to have to do some modifications anyway.
I've attached a couple of pictures for your review.
I checked Mouser, Digikey and Amazon without success. Does anyone have an idea where I can find a shallow 3 prong receptacle like this? Or should I just stick with the 2 prong and move on?
Attachments
Figured I would update my own post. Thanks @cowanaudio for the suggestions! I knew those were an option, but I wanted a cleaner look.
As it turned out, finding a grounded, shallow receptacle like the original is pretty much impossible. They just aren't made, so this is what I came up with.
The hole in the case was roughly 1" when the old receptacle was removed. I was able to find a PVC adapter and nut that fit everything perfectly. I rewired everything, including a new grounded plug, cord, and fused the load side of the receptacle. It was tight in that little case when I was done, but I did get everything to fit. All connections are either soldered, or crimped with solderless connectors and heat shrink.
A little paint, and elbow grease cleaning up the inside of the coil and the dial, and we are back in business. I'm really surprised how accurate this unit is, given its age. Some of the YT videos I have watched have complained how the newer Chinese Variac voltages are way off compared to the dials, but this one is balls on.
This project was a little out of the ordinary, but was a lot of fun.
As it turned out, finding a grounded, shallow receptacle like the original is pretty much impossible. They just aren't made, so this is what I came up with.
The hole in the case was roughly 1" when the old receptacle was removed. I was able to find a PVC adapter and nut that fit everything perfectly. I rewired everything, including a new grounded plug, cord, and fused the load side of the receptacle. It was tight in that little case when I was done, but I did get everything to fit. All connections are either soldered, or crimped with solderless connectors and heat shrink.
A little paint, and elbow grease cleaning up the inside of the coil and the dial, and we are back in business. I'm really surprised how accurate this unit is, given its age. Some of the YT videos I have watched have complained how the newer Chinese Variac voltages are way off compared to the dials, but this one is balls on.
This project was a little out of the ordinary, but was a lot of fun.
Attachments
Thing to remember is that a Variac is just a single winding with a sliding tap on it. That means that although it is a transformer (an autoformer), it does not provide galvanic isolation from the mains the way a 2-winding transformer would. I use an isolation transformer. Plug the Variac into the isolation transformer, and the isolation transformer into the wall outlet. Don't do it the other way around. I understand that 'Variac' is a brand name for the device, and the name got so popular that all brands of the adjustable autoformers get called that. It's sort of like facial tissues, which often get called Kleenex, no matter the brand.
Thanks @egellings, a great reminder. I actually watched a YouTube video on that exact thing. It was not something I never thought of before and it made a lot of sense. I am not planning on doing anything too dangerous in the near future, but an IT is on the list, nevertheless.
The only thing I have now is a DBT for testing audio equipment, and I wanted something a little bit more. I figured dropping $5 on this and then making it a bit safer was worth the money.
The only thing I have now is a DBT for testing audio equipment, and I wanted something a little bit more. I figured dropping $5 on this and then making it a bit safer was worth the money.