static phase converter

kelLOGg · June 22, 2007, 06:34:26 AM

I just purchased a Powermatic planer model 160 at an auction. It is operated by a 5 HP 3 phase motor and I have only single phase available. The least expensive option I have found to operate this motor is a PHASE-A-MATIC model PAM-600-HD (from Surplus Center for $200). According to specs it will operate a 3 - 5 HP motor. Do you think this unit will start and operate my planer? I realize it will reduce available HP to 2/3 so I will effectively I will have a 3.3 HP planer but the specs on the planer say it is designed for a 3 to 7.5 HP motor.

Bob

Don P · June 22, 2007, 06:47:10 AM

It will run it but with a little searching you should be able to come up with an old 3 phase motor you could make a rotary out of ???

scsmith42 · June 22, 2007, 01:31:42 PM

Bob, typically you upsize the motor on your converter by 30% or so to make up the loss. IE - if you want to operate a 5HP motor, you use an 8HP phase converter, etc.

I think that the Surplus Center coverter may be just a bit undersized for what you want to do.

Scott

jrokusek · June 22, 2007, 01:39:14 PM

I see that Grizzly has static phase converters too. http://www.grizzly.com/products/g5843

gharlan · June 22, 2007, 03:32:46 PM

I do not understand why you would not just make one. All you need is an old three phase motor and they are everywhere for cheap. I have been using my current one for about 8 years. I made it out of an old 100 horse motor I bought from a guy for 15 dollars. It runs the shop with multiple operators just fine. But my largest single motor is a 30 hp. Before that i used a 25 hp and before that it was a 15. I have never had a problem and they are cheap. Just make sure it is a low voltage three phase. Most can be either way but if it has been rewired it may just be one voltage. I also seem to recall a certain wound motor works better than others. I am not sure which one or the types right now but I bet someone on the board could tell you.

scgargoyle · June 22, 2007, 04:55:06 PM

Do a google search for making a rotary phase converter. As others have said, it consists of a 3 phase 'idler' motor which is run on a static converter, and your current single phase is run through the motor, making true 3 phase. I've seen plans that include how to make the static part of the converter, too. I think mostly all it consists of is some big capacitors to start the motor.

gharlan · June 22, 2007, 06:14:43 PM

While using capacitors to start the "add a phase" makes life simple it is not necessary. I used capacitors on my early converters but always had a problem with a guy that could not remember to turn the capacitor back off after start. After a bit--poof--capacitor pop corn. My solution to this constant occurance was to start the motor with a pull rope. I used a rope with a knot in one end and a handle on the other. Hang knot in the keyway on the motor shaft, wind rope around shaft, pull like a lawnmower. Once spinning turn on the 220 power to the motor. The motor will come to speed and you have added a third leg for your three phase.

With my current 100 horse motor pulling with a rope is a bit tough. It has a three inch shaft so I had to wrap a rope and take off running!! It was a lot of work and funny to watch I am sure. As a solution I took an old three horse single phase motor and hinged it off the 100 horse. I put a sheave on both shafts. I start the single phase with a belt between the sheaves but loose enough to slip. After it is at speed I pull back on the single phase to make it engage and turn the three phase. After the three phase is moving good I turn off the single phase and turn on the three phase. I then relive any belt pressure remaining and let the belt flip to the floor. This takes a moment to start but gives you a phase converter without having to purchase anything other than a used three phase motor. I have used these for years. In a few cases I have the same machine in both three phase and single phase. There is no comparison --the three phase will out work the single every time.

Don P · June 22, 2007, 06:56:32 PM

QuoteI also seem to recall a certain wound motor works better than others.

I think its supposed to be Delta wound instead of Star ???.

TexasTimbers · June 22, 2007, 09:27:39 PM

Just don't buy a cheap convertor. I did and in order to be cheap they use cheap chinese motors. I have been listening to the ball bearings rattle around in there since I flipped the swith the first time.
It hasn't given up the ghost but I cringe everytime I use my table saw. You know it is going to scrap out at the worst possible time.

I have been keeping an extra 15HP motor around for when that happens.

kelLOGg · June 23, 2007, 07:29:40 AM

Hey guys,
Thanks for encouraging me to make my own rotary converter. I read the threads on phase converters and found the one started by Kelvin very helpful. I found a web page for phase-a-matic 3 phase which pretty nicely explains how to use a static converter and an idle motor to make a rotary converter. So here is my plan: purchase a 4 - 8 HP static phase-a-matic. This will operate my 5 HP planer at 2/3 power. Scrounge a 7.5 HP 3 phase motor and wire it in as described in the web link. I should have near full power 3 phase not only for my planer but future tools as well. Does this sound OK?
Bob

Larry · June 23, 2007, 07:54:32 AM

Since you decided to go the D-I-Y route here are a few links you can study on.

http://waterfront-woods.home.att.net/Articles/phaseconverter.htm
http://www.metalwebnews.com/howto/phase-converter/phase-converter.html
http://www.homemetalshopclub.org/projects/phconv/phconv.html
http://www.metalwebnews.com/howto/ph-conv/ph-conv.html

I've built several static converters from info in the first link. One rotary converter using a little info from all of the links.

There is a company in Joplin Missouri that even sells an engineered kit for a rotary converter. All you supply is the motor. Can't remember the name of the company off hand.

Den Socling · June 23, 2007, 09:18:21 AM

Through most of my life, I had more time than money and did everything myself. But last year when I needed a phase converter, I bought one plug & play. I soon saw problems. Freq drives would slow to a jog instead of stopping. (This is not good if you are watching your bridge crane running out of runway.) The problem turned out to be a voltage imbalance. After talking to three people at the RPC manufacturer, I was sure the problem was the capacitors. The RPC is rated 30HP and needs a load on the bank of capacitors. I split the capacitors into three banks. I use one for loads up to 10HP. I add a second for loads up to 20HP and the third for full loads. That fixed the voltage problem.

scsmith42 · June 23, 2007, 12:49:31 PM

Bob, most of your plan sounds OK. However, I think that you're taking a risk by "operating your planer at 2/3 power". The risk is that you'll burn out your planer motor due to a lack of needed current.

I think that you're better off either buying or building a converter that's large enough to completely meet your planer's current requirements.

Gharlan's comments about homebuilt converters are right on; I have three converters - and one is built as he mentioned. Rather than using a rope, I simply spin the shaft with my boot before turning on the power.

Scott

TexasTimbers · June 23, 2007, 01:46:04 PM

To amplify on what Scott said, underamping will burn it up just as quick nearly, if it is too drastic. If you don't have a amp meter then buy or borrow one until you get it ironed out. Knowing that your motor is pulling the RLA (Running Load Amps) , which are stamped on the nameplate, is the only sure way to know.

Don_Lewis · June 23, 2007, 11:30:52 PM

Life is way too complicated. Just buy a single phase 5 hp motor. You can buy single phase motors to 10 HP.

kelLOGg · June 25, 2007, 09:34:50 PM

I hope I'm a little more educated now. I've read the web pages on making a rotary converter and you guys' comments and have modified my plan based on the same. What does this sound like? purchase a PHASE-A-MATIC 15587 Static Phase Converter Heavy Duty 4 To 8 HP Range 220 VAC unit and follow the Phase-a-matic Method 2 instructions phase-a-matic using this unit and a 7.5 HP 3 phase idler motor to make a rotary converter. The instructions seem to be pretty clear.

One more question: My planer motor came with a magnetic starter. Do I feed the output of my soon-to-be rotary converter into the mag starter or do I no longer need the mag starter?

Don_Lewis · June 26, 2007, 07:27:58 AM

You still need the starter and overloads.

gharlan · June 26, 2007, 09:11:00 AM

Not to add more to your to do list kelLOGg but you will need to look and see how the motor on the planer is wired. If it was in use as a low voltage three phase then you should be good to go. However if it was in high voltage use then you will have to switch the wires around to low voltage. The heaters that will be installed in the overload will then not work on the low voltage(the planer will run but kick out after a minute or so). There should be a chart on the inside of the starter cover listing the heater sizes for the voltage. you will have to hit an electrical supply house for the proper heaters and they will have to order them as a rule.So checking now allows you to have them when you have it all ready to go otherwise. It was frustrating to me to finally get my new toy hooked up and then it will not run long because of some $2 heaters.----good luck I have that same planer--you will like it---gary

shopteacher · June 28, 2007, 05:14:47 PM

My current phase converter is made out of a 20 hp 3 phase motor with a bank of run capacitors and a start capacitor. The start cap is connected to a potential relay that drops out the start capacitor when the amperage increases. This keeps from blowing out the start cap. I had a momentary switch connected to the first one I built and would hold it in until the 3 phase came up to speed then would let it go to break the circuit. This new one starts by remote control. Makes it nice cause you can start and stop it anytime and from anywhere you want. It wasn't that hard to build and just took some tinkering around till I got it to work the way I wanted it to. There is only a couple volts difference between any of the three voltage legs. I had to keep changing the run capacitance till I got it fairly well balanced. I had made up a schematic for it somewhere. If I find it I'll scan and see if I can remember to post on here.

solidwoods · July 10, 2007, 07:38:07 AM

Build a rotary type.
20hp or so (you may add on tools,, like a 10hp dust collector for $25+shipping).
Planer is a high load application, if the converter can't,, well you know.
jim

Ironwood · July 13, 2007, 11:04:17 PM

From the questioned asked, be careful. IF you need answers to some of the questions then perhaps you could go to a local "Motor" shop and have them take care of the details. My local shop built a balanced 30 hp with my scrap yard motor, mag starter, safety switch and box, combined with a new monentary timer and new capacitors for $200. A bargin just in my savings of time. Be aware that 3 phase breakers are pricey if you are putting in a panel. If it only one machine and no larger plans for the future, like the man said "just go get a single phase motor"

reid

Gary_C · July 14, 2007, 10:47:40 AM

For a 5 HP motor, Don is exactly right, again. Save all this trouble and just buy a single phase 5 horse motor and go to work.

If you want to get technical, you cannot overcome the slight reduction in power from 3 phase converters by using a larger converter. The power reduction is caused by attempting to convert two-180 degree out of phase legs to 3-120 degree out of phase legs.