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3 phase converter running RC63 planer

Started by Greenie, October 09, 2018, 08:17:00 AM

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Greenie

It's an old Rockwell RC63 planer 24" with a 7.5 HP motor. An old Ronk 3 phase converter runs the planer. The Ronk is starting & stopping then tripping a breaker. 4 years ago an electrician replaced the ronk motor but didn't do anything (I think) to the 3 phase converter control box. The box smelled of burnt electrical odors but there's no visible damage, not much for parts except for 6 capacitors. Even with the planer disconnected the 3 phase converter is on/off rapidly. The 3 phase motor does not smell.
We have lots of wood to plane but can't get the electrician back until November because they are booked out that far. I'm thinking about trying to repair or replace myself.
Any ideas on what's wrong?
I can buy a 10HP 3 phase converter - are they plug & play or is there a lot of wiring to do?
Replacing the 6 capacitors, if I can find them but I hate to waste time and spend money if the capacitors are not the problem.

Any help would be appreciated!

YellowHammer

You can build phase converters.
You can repair them as well.
Or you can buy them, and American Rotary is one of the best, if not the best, in the market.  It was the only brand that the dealer of my Straight Line Rip saw would allow me to use to honor my warranty.  My operation gets inspected routinely by my insurance company, fire department, and TVA Energy, and when they see the American Rotary converter, they just nod and say "good". 

Very balanced electricitybetween the L1, L2 and L3 legs, very quiet, very nice.  They are easy to install and come with a lifetime warranty.  Get a bigger one than you need because once you go to three phase you never go back.    
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

Don P

Carpenter not an electrician, warning Will Robinson :D

So the rotary motor is not getting up to speed under no load before the relay is kicking off the start capacitors, it fails to "start (doesn't spool up)", stalls and then trips?
That sounds like a start capacitor is shot, there are tutorials online for testing them, next guess would be the relay has burnt contacts or winding. Those should be all pretty quick checks. Do discharge the caps before handling them by shorting across the contacts, with glasses on just in case. Rapid cycling of those, many on off cycles without cooling time isn't good for them. My neighbor blew some setting up one.

DMcCoy

I tried building my own off plans on the internet.  I worked but not too good.  I second the American Rotary recommendation.   I bought one a couple of years ago and it works great and the weird high pitched motor noise that I got with my home made version disappeared. 

muggs

Hi Greenie, I build converters. Are you saying that the only thing in that control box is metal oil filled capacitors?

Crusarius

Greenie, you do not mention if it is a static converter or rotary converter. When I read what you have it sounds like static converter. If that is the case you probably have lost a capacitor and cannot get enough power to get it up to speed before the third leg drops out. I blew up one of the static converters on my vertical steel mill and replaced it with a VFD. The VFD was a very nice upgrade. It has direction and speed control built right in.

Greenie

"Hi Greenie, I build converters. Are you saying that the only thing in that control box is metal oil filled capacitors?"... That's all I see - six aluminum oblong cans wired together. I'm not sure if they are 1970's vintage or newer. There is no relay I can see, just wires to bus bars and the outlet to the planer. This control box is wired directly to a motor with no external shafts.

Greenie

"Greenie, you do not mention if it is a static converter or rotary converter" I think it's a rotary. There is a motor with no external shafts that spins up when we start the 3 phase converter separately and prior to starting the planer. 

muggs

OK We can go from there. If that is all there is in the box. They used the high resistance rotor method, perfectly fine. You probably have a bad capacitor. The metal ones like you have usually bulge out when they go bad. But not always. You need to find someone with a multimeter with a capacitor scale on it to check them. If the electrician can't come out, how about a motor shop near you. If the caps check out, then we look at the motor.     Muggs

Greenie

Yes, there is a motor shop here in Bangor. I'll bring the box and maybe the motor to him to check.

muggs

Good deal, let us know what you find out.    Muggs :P

Greenie

All six capacitors tested OK today, I'm back at square one. Most electricians in these parts are booked out until next spring and few have any interest in taking on this job even then.
As further elimination I think I'm going to rent a 50KVA diesel generator - they mostly all have 3 phase outputs - and run the planer on that for a few hours to make sure it's not the planer. It's $160 a day to rent the generator. If the planer runs fine on the generator then I'll order a American Rotary 3 phase converter and be relatively assured that once it arrives and is installed I'll be all set.

muggs

Your next step should be to take the motor to the shop and have them check it out.   ::)   Muggs

Greenie

The motor for the 3 phase converter?  The shop that tested the capacitors declined to check the whole unit - he's 82 years old and scaling back. That leaves no one that I can find to check the rotary phase converter until next spring. Renting the diesel fired generator for $160 will tell me if the planer motor works. I don't have any other options available if I want the planer running again.

YellowHammer

If you go with the American Rotary, I recommend getting their inexpensive, lighted remote switch.  I mounted my phase converter, 25Hp, out of any dust and such in the overhead loft.  I mounted the remote switch right next to the tools, and when I'm ready to run, I rotate the 3 phase switch to on and it lights up letting me know the converter is running.   
YellowHammerisms:

Take steps to save steps.

If it won't roll, its not a log; it's still a tree.  Sawmills cut logs, not trees.

Kiln drying wood: When the cookies are burned, they're burned, and you can't fix them.

Sawing is fun for the first couple million boards.

Be smarter than the sawdust

muggs

Quote from: Greenie on October 12, 2018, 03:23:29 AM
The motor for the 3 phase converter?  The shop that tested the capacitors declined to check the whole unit - he's 82 years old and scaling back. That leaves no one that I can find to check the rotary phase converter until next spring. Renting the diesel fired generator for $160 will tell me if the planer motor works. I don't have any other options available if I want the planer running again.
In your original post, you said with the planer disconnected the converter still would not work. So yes the converter motor.   All you have to do is find someone with 3 phase power, to try out the converter motor.  Muggs

Larry

All of the rotary phase converters I've seen have a potential relay that energizes a capacitor at startup.  Once the motor is up to speed the relay takes the capacitor out of the circuit.

Maybe your converter is a design that doesn't have a relay, but its something that I've never seen.

From the symptoms it sounds like the converter motor is never reaching operating speed.  I would guess a bad capacitor first, than the potential relay.

I believe Ronk is still in business.  Have you tried call them?

Larry, making useful and beautiful things out of the most environmental friendly material on the planet.

We need to insure our customers understand the importance of our craft.

Greenie

The problem, I discovered was the 240 volt feed to the Rotary phase converter. I should have logically and systematically gone about troubleshooting in order but I did not. First thing was I should have made sure the input power was good. As it turned out the 60amp double pole circuit breaker heated up where it connected to the bus bar in the circuit breaker panel. One contact had heated up and the tension on the bus bar was compromised. Further use heated up and allowed resistance to ruin that connection. By the time I looked there was not very much left of the circuit breaker panel connection. I relocated the double pole breaker down to the next slot to a better position and all is good.
Thanks for the help and for allowing me to be an example to avoid while troubleshooting... ;)

muggs

I like simple solutions.  8)    Muggs

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