Need Help Understanding This Thing

[oughtsix]

I just bought a "new " toy. The owner had not ran it for 35 years, and I don't know how much older it is. (there were animal bones in the box it came in, so I don't know if I need to hold the bones over it and chant or not) Before I plug it in I would like to understand what is going on. I've attached photos of the phase converter box ( a VFD?) and an attached panel. The yellow cord is the power supply and that feeds the switch(not shown).

I understand basic wiring, but this is beyond me at the present. So my questions are: How does the current move through this thing? Does it look safe?

 

[Firestopper]

I'm no expert, but I believe what you have is a static phase converter. The three rectangular and single round items are capacitors. I have never had much luck with static converters. I run a rotary phase converter to power the machines in the shop. You can run the machine on a VFD, but that will require more knowledge to set up as well as more money, assuming this is a three phase machine.

 

[JimDawson]

My concern would be the capacitors. After setting for 35 years they are probably bad. I would look into installing a VFD, it might be the least cost option.

If you go with a VFD, save the reversing motor starter (on the right), you can use it for something else down the road.

 

[brino]

My concern would be the capacitors.

ditto here.....capacitors tend to "dry out" over the years. If not totally dried out, it _may_ be possible to "reform" them by applying low voltage and slowly raising it higher , but you'd want to take them out of the circuit to do that....

Plugging them directly into high "mains" voltage may find the problems immediately......but it could be dangerous (smokey and explosive!).

It looks like you have a static phase converter like this:
http://www.homemetalshopclub.org/projects/phconv/phconv.html

Also see here for disadvantages of static phase convertors:
http://www.openelectrical.org/wiki/index.php?title=Phase_Converter

-brino

 

[RJSakowski]

The rectangular capacitors are most likely oil filled and should be OK. The cylindrical capacitor looks like an ac electrolytic. dc electrolyics can be reformed but I have not heard of that being done to ac electrolytics. They are two dc electrolytics connected in series with opposing polarities so there is no way to apply a dc forming voltage.

 

[John Hasler]

I just bought a "new " toy. The owner had not ran it for 35 years, and I don't know how much older it is. (there were animal bones in the box it came in, so I don't know if I need to hold the bones over it and chant or not) Before I plug it in I would like to understand what is going on. I've attached photos of the phase converter box ( a VFD?) and an attached panel. The yellow cord is the power supply and that feeds the switch(not shown).

I understand basic wiring, but this is beyond me at the present. So my questions are: How does the current move through this thing? Does it look safe?
View attachment 104961

View attachment 104962

It's a "static converter". Looks safe. In effect, it turns a three-phase motor into a capacitor-start capacitor-run single-phase motor. I made one for the three-phase 3hp motor on my mill. Works fine, but it is *not* a no-moving-parts replacement for an RPC and it does not provide variable speed like a VFD does.

 

[John Hasler]

The rectangular capacitors are most likely oil filled and should be OK. The cylindrical capacitor looks like an ac electrolytic. dc electrolyics can be reformed but I have not heard of that being done to ac electrolytics. They are two dc electrolytics connected in series with opposing polarities so there is no way to apply a dc forming voltage.

I've used decades-old AC caps like that with no problems. Try it. If the motor hums but won't start replace the cap and try again.

 

[chips&more]

Somebody needed to convert/trick 1 phase to run a 3 phase motor. If you do not have 3 phase source power, only 1 phase? Then you need one of these or alternatives. If you are not on a budget, then I would go with a VFD. If you are on a budget, then keep what you have, and try it out. Hook it up and test it. Make sure your power source is breaker/fuse protected. You will probably find out in the first second or two if the thing is going to work. I can’t see any damage being done to the motor in that kinda time if the cap(s) are bad. Maybe a growl from the motor or a puff of smoke from a cap(s). Just be prepared. Stay out the way and have a fire extinguisher handy. Not trying to freak you out, but just want to see you be safe. You might be surprised and find out it works. You can always check the caps with a meter before you proceed. Take them out of circuit first. Good Luck, Dave.

 

[oughtsix]

Thanks for all the replies. It is a 1 HP 3 phase motor running off 240v . It will be a few days before i power it up ( I'll get the right fire extinguisher, too) . May even have to video the startup if it might explode!..

-06

 

[coolidge]

Caps can explode and make a mess and stink.