Need Some Elec. Motor Help!!

[Minnesota_boy]

Most common meters measure the DC resistance, voltage, or amperage.  To test the motor you need an AC impedance measurement.

[J_T]

You can wire differnt capasitors together to get 55mfd .A phase converter is no problem ask Frier Don. Big Co's like to make some things look hard to do .

[Kevin_H.]

My wife went to town today, she found a place that had the right run cap in stock for 20 bucks...but she didnt get it cause I had ordered one already. :(

Hey J T
I looked at a phase converter and it looked like a bunch of capacitors wired together...but my knowage is limited

Again if the new cap doesnt fix it i will take off the motor and take it to town.

Hey Don, did you make your own converter?

[D._Frederick]

Kevin,

There is one more thing you can try if you got more time than money. The single phase motors have a centrifical switch that have points. If the motor has sit around a lot, the points can be corroded or the moving part rusted so that they do not move. To check this switch, take off the end bell opposite the output shaft. The end bell has 4 or more bolts on the rim and there are two bolts that hold the bearing. After the bolts are out, just tap it apart.

You can check the starting caps (the caps with black plastic cases) to see if they are good. Take a couple 12 volt car batteries and connect them in series, - to +, - to + , connect the cap to the + and - leads from the battery.  Discharge the cap and you should see a nice spark if the cap is any good.

When you have it (the motor) apart look at the armature windings, if any are black and  smell.   Throw the motor in the junk pile.

[J_T]

Hey D much easer to use cheap ohm meter. I beleave Don made a rotery converter the one you are refering to is a static converter. Rotery is better most factory converters use a static to start their rotery one . Don posted a link to a site on such things once I think I sent it to him. Worked seven years selling hardware ,elect. and plumbing. Would post link don't know how that why I sent info. to Don. Me and man up the road built a 50hp he uses every day.

[shopteacher]

Kevin you could take an ohms meter and check each incoming lead to the case of the motor.  If you get a reading you got a short to ground.
   Me, I'd put a three phase 10 hp. on it and build a rotary phase converter.  All you need to make a simple, but balanced converter, are some run capacitors, a start capacitor, a momentary switch and a good older cast iron frame 10 hp motor. (could be larger to run a 10 hp motor)  You can use the newer motor, but they don't seem to work as well, something about making the newer ones energy efficient.
I just built two, one a 5 hp. and a 10 hp. converter.
Here's a thread I posted a while back on a converter I was making if you go toward the end I think you'll find some pictures of the components.
https://forestryforum.com/cgi-bin/board/YaBB.pl?board=general ;action=display;num=1073845355

[J_T]

Shopteacher on our 50hp we use a small 110 motor to start it cheper than capasitors it you have to buy them I don't  I got a bunch on hand . I would make sure to enclose all capasitors as I have seen them explode .I don't post anything I haven't tried myself for some reason I didn't post much when you were building yours maybe cause me and Frier Don all ready did it on the FF.

[Kevin_H.]

Thanks for the links...very interesting...I hope the single phase motor will come to life, but If is doesnt I will be tempted to park the gang until this summer, our plan is to have 3 phase in the new shop.

We are only about 100 feet away from 3 phase now, but no since running it in if we are going to move.

Hey Teach, I will try the ohms meter test on friday, It might save me any more work.  :(

[shopteacher]

J_T  using a pony motor to start the three phase is one way of doing it.  However you only achieve approx. 80 efficiency from the converter motor and probably don't have a very balanced output voltage.  If you check between each of the three output leads you will probably see one leg with much higher voltage.  The converters I built were deriving an output voltage of only 2 volt difference between any of the output leads.  I had a converter connected to my milling machine that had that one high voltage lead and the motor would get so hot it would kick out the thermal overloads in the starter.  You can also get a static converter that is basically just a start cap and a potential relay. The start cap kicks the three phase motor over and the potential relay disconnects the capacitor once voltage is detected in the manufactured lead. They're cheaper to purchase but here again the motor is only running at about 80 %.

[J_T]

Shop teacher our 3ph reads 110-110-180 call it wild leg common around here . Our converter been running over a year ever day . No converter puts out 100%. reson we went 50hp got several peaces on line can run several small things on same converter same time up to or around 40horse 35 is good. Some times you can get 25hp motors almost free here.

[shopteacher]

Your right J_T no converter will put out 100%. The readings between any two of the three legs on mine are 240, 238, 239.
The general consensus as to what you can run is no one motor bigger than the motor used for the converter or a combination of motors totaling twice the converter motor.  10hp can run a total of 20 hp with no one motor exceeding 10hp.
    I'm not saying you don't have a good system and know quite a few shops that run converters exactly like the one you mention. I was just siting an situation where it didn't work out to well.
     The 10hp I built has a remote control. As it will be stationed in a 2 story building. I don't want  it to run constantly so this way I can start and stop it at anytime or anyplace inside the building. A lot of my equipment is single phase and only need 3 phase when using particular pieces.
     Your right about getting three phase motors cheap. I paid 27.00 for the one I used and it weighs 400 lb so I think I could get more for as scrap than what I paid.

[D._Frederick]

J. T.

I would like to know what kind of 3 phase motor that you have that will run on 110 volts?

I agree with you that you can do a lot of trouble shooting using a ohm meter, but you have to have a wiring diagram of the motor. Some times you can find out the problem by just looking.

[D._Frederick]

J. T.

I guess that I misread you post about the voltages, I thought that you were reading your converter voltage instead of the line voltage from the power company.

[shopteacher]

D, I think he is reading output to neutral. Two of the output leads will give a reading the same as the source voltage. The manufactured leg (wild Leg) will be a much higher voltage in this case 180 V.  I just feel you can get a much closer to true three phase using 2 banks of capacitors.  By taking readings and adjusting the capacitance you can get the output voltages very close.

[Kevin_H.]

 8)

Well we got the electric motor to run today...We replaced bolth run caps. but still had a problem so we went back to square one and found that to of the leads in the wireing box were mismatched, Something like T5 and T8 were wired up backwards...

Anyway we made a little sawdust before calling it a day.

Just a little side note for Electric al...Linda was right... the rear roller is a pain in the keester, but we have a plan.

Stay tuned for "As The Saw Turns"

[Fla._Deadheader]

  Way to go, Kevin. Perseverance pays off one more time. 8) ;D :D

[Stan]

Teach, 80% power factor is the way 3 phase alternators are rated. The thermal plant I worked at they were rated 156,250 kW at 80%. We usually got 180,000+kW out of them.