# electric motor hums doesn't start spinning....



## holtzdreher

I was given a small made in china drill press. It has worked very well for over a year. (It was a couple years old when given to me) Just this past week, when I switch it on, it just hums and it won't start turning unless I spin the chuck to start it. Obviously something is wrong. It has been running well up to this past thursday. I hate to just trash it. What could be causing this, capacitor, brushes?


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## Larry42

Most likely the start capacitor has died. I seriously doubt that it has brushes. The capacitor will have information printed on it that you can use to get a new one. Look it up online. Should be pretty cheap. Quit trying to start it w/o the capacitor or you may burn up the motor. There is a centrifugal switch on the fan end of the motor (inside) that could also have failed. But the capacitor is more likely. Electrolytic Chinese capacitors are prone to failure. Easy fix.


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## Catpower

Could be the start cap but it might be the centrifugal switch, when start caps fail they generally blow apart, before you turn it on the next time give the motor a pretty good smack on the opposite end of the shaft. There might have been a piece or dirt or something that was under the contact in the centrifugal switch

I have "fixed" many split phase motors doing it


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## Larry42

If your motor has a capacitor it is not a split phase motor. Split phase motors have very poor starting torque so you won't find them on tools of any size. They do however have centrifugal switches that can fail. Dirt can get in between the contacts like said. The contacts can also arch and get a "tit" on them that prevents good contact. Or, they can just be so poorly made that they have no durability. If it is dirt you might be able to vibrate it out by tapping vigorously on the motor shaft. If you are mechanically inclined you can take the fan end cap off the motor and see if there is a burned contact & file it smooth or determine if the mechanical mechanism will function. Watch out and don't lose the wafer spring in the bearing housing. 
Cheap tools with even cheaper Chinese motors are made for only one purpose, to sell them.

The Chinese are capable of making quality tools but that isn't what the importers want to buy/sell.


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## Catpower

Larry Schweitzer said:


> If your motor has a capacitor it is not a split phase motor. Split phase motors have very poor starting torque so you won't find them on tools of any size. They do however have centrifugal switches that can fail. Dirt can get in between the contacts like said. The contacts can also arch and get a "tit" on them that prevents good contact. Or, they can just be so poorly made that they have no durability. If it is dirt you might be able to vibrate it out by tapping vigorously on the motor shaft. If you are mechanically inclined you can take the fan end cap off the motor and see if there is a burned contact & file it smooth or determine if the mechanical mechanism will function. Watch out and don't lose the wafer spring in the bearing housing.
> Cheap tools with even cheaper Chinese motors are made for only one purpose, to sell them.
> 
> The Chinese are capable of making quality tools but that isn't what the importers want to buy/sell.



There are four different single phase motors, a shaded pole has a single winding with a copper shunt in the field to cause rotation, to change rotation just flip the field over. A split phase motor has two windings a start winding and a run winding, the start winding splits the phase from the run winding and that winding determines the direction the motor will run. A capacitor start motor is a split phase motor with a capacitor parallel with the run and start windings that only stays in parallel until the motor is at about 75% full speed. A permanent split capacitor motor has a run capacitor between the start and common windings to utilize the back EMF of the start windings to increase efficiency, a capacitor start cap run motor uses both a start cap for increased start torque and a run cap for increased efficiency


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## woodnthings

*So ... we are agreeing here?*



Larry Schweitzer said:


> If your motor has a capacitor it is not a *split phase motor*. Split phase motors have very poor starting torque so you won't find them on tools of any size. They do however have centrifugal switches that can fail. Dirt can get in between the contacts like said. The contacts can also arch and get a "tit" on them that prevents good contact. Or, they can just be so poorly made that they have no durability. If it is dirt you might be able to vibrate it out by tapping vigorously on the motor shaft. If you are mechanically inclined you can take the fan end cap off the motor and see if there is a burned contact & file it smooth or determine if the mechanical mechanism will function. Watch out and don't lose the wafer spring in the bearing housing.
> Cheap tools with even cheaper Chinese motors are made for only one purpose, to sell them.
> 
> The Chinese are capable of making quality tools but that isn't what the importers want to buy/sell.





Catpower said:


> There are four different *single phase* motors, a shaded pole has a single winding with a copper shunt in the field to cause rotation, to change rotation just flip the field over. A *split phase motor* has two windings a start winding and a run winding, the start winding splits the phase from the run winding and that winding determines the direction the motor will run. A capacitor start motor is a split phase motor with a capacitor parallel with the run and start windings that only stays in parallel until the motor is at about 75% full speed. A permanent split capacitor motor has a run capacitor between the start and common windings to utilize the back EMF of the start windings to increase efficiency, a capacitor start cap run motor uses both a start cap for increased start torque and a run cap for increased efficiency


I don't see any difference here... just me?


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## Catpower

woodnthings said:


> I don't see any difference here... just me?



A capacitor start motor is a split phase motor with a start cap in the circuit

I should have said there are two kinds of modern single phase motors, a shaded pole and split phase, a cap start, PSC and cap start and cap run are just variations of a split phase motor

Many moons ago there used to be induction start motors they had on them what they called a necklace basically a universal,motor used to start the motor. The necklace had brushes it it but it was dropped out by a relay or centrifugal switch


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## Larry42

If you ask for a split phase motor, you won't get a cap start or cap run one as an option! It's a terminology thing.
Too bad in the US we can't get 3 phase power in residential from the power company. In Germany you can. 3 phase has many advantages. 
If I have the option of 3 phase or single when buying a tool I'll always go for the 3 phase. 
For any of you guys w/o 3 phase you can home build a rotary phase converter for a lot cheaper than buying a commercially made one. Long ago I ran on one for 5 years before moving to a commercial location. They are simple to build. Required parts; a used 3phase motor, some big electrolytic capacitors, two switches and a box to put it all in (just incase you blow one of those big caps!) The caps provide the 3rd leg kick to start the motor spinning. The motor will be a generator making 3 phase. Your driven motors will only develop about 80% of fully rate power, but you rarely use the full rated power on most tools for other than a very short time. So don't pass up a great deal on a used tool just because it is 3 Phase. I suspect all the information for this setup is available online. I'm so damned old that there wasn't an internet when I made mine. Mine was based on an article in Fine Woodworking. I had asked an electrical engineer about it but he assured me that it wouldn't work. I didn't tell my machines that. Don't use this system on motors that require constant full power (dust collectors, pumps, etc..)
Nice thing about 3 phase is instant reverse. Like when power tapping on my mill. 
Most of the new front load washing machines run on internally developed 3 phase so they can utilize electronic variable speed. 
My edgebander has an electronic frequency converter. It ups the normal 60 hz to 240 hz making the 3 phase trim motors run @ 14,000rpm (14,400 sincro.) You can up the speed of any 3 phase motor by just feeding it higher frequency, too much higher and it may fly apart! An older machine I had used a rotary freq changer, basically a motor generator set. You can also slow a motor the same way but cooling becomes an issue.


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## holtzdreher

well I pulled the capacitor and ordered a new one from a shop in the county. Should be here friday with free shipping.


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## Catpower

You can also build a phase converter using a starter motor to get the 3 phase motor running once it is up to speed kill the starter motor and energize the ballast motor with 240 it will continue to run on single phase and generate the third leg off L3.I have been using one I built for about 22 years for my Axleson lathe. It is best to size the ballast motor twice as big as the biggest motor you plan on operating, and they claim a two pole motor is better than the four pole motor, but I have used them both without any noticeable difference 

If you are using a VFD, try to find a motor with Type F insulation, if you are going to pull it to rated load, VFD's basically rectify the AC to DC and the motor operates on pulsating DC. It is also a good practice to install a grounding ring like an Aegis, on the frame to haft to ground the shaft to prevent bearing pitting if the motor is going to be run a lot

The first VFD I ever worked on used vacuum tubes for the rectifiers, they have come a long way since then

I have forgotten quite a bit of the stuff I used to work on daily for about 40 years, every kind of motor from an 1/100hp to a 17,500 HP Westinghouse compressor in a Union Carbide air separation plant, they also had a slew of compressors 8,000, down to bout 500 hp. and they were all 4160 volt, you made sure everything was locked out and tagged out, it was not forgiving.

They had to pay their electric bill every 10 days and it ran about $550,000, and that was about 30+ years ago,then Bophal India happened and I lost my bird nest on the ground LOL


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## Larry42

CAT, I've been surprised at how small the electronics can be in the VFDs. We've got quite a few of them on our equipment. They are all running on 380/400 or 460/480V. We have 800amp 3 phase coming into the shop. The last tool we had installed the electrician warned us about having hit the max draw for the mains. They sure are proud of those I-line breakers!
We are moving our offices to a different spot in the building so the sprinkler system needs some changes, another expensive thing! It never ends.


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## Catpower

They have come so far with the drives it is amazing, I worked at the Bureau of Engraving in Ft Worth for a while, it was built form 1988-1990 and they used all the latest equipment, I got a lot of experience on those drives, a 7 1/2 hp was about $30,000 and was bigger then the MC panel was.hell the gate drivers were bigger than a 7 1/2 hp drive is now

I see that there are some companies making a 5 hp vfd for single to three phase operation, be nice if they finally get up to 10 hp

I have a Phase Perfect digital phase converter that I used on my Hy Def plasma table, but I got rid of the table, still have the $12,000 drive. I plan on fining a good 37 inch or so Timesaver, the phase converter will handle up to 40 hp, and it puts out better three phase then the utility companies do.

But that isn't saying much the power grid kind of dumps all the electricity generated together, and consider a sine wave of 60 cps electricity is 2300-2800 miles long (depending on who you listen to about the speed of electricity) when the beginning of the sine wave hits you machine the tail of it hasn't left the power plant LOL


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## holtzdreher

well the capacitor had no effect. So I took the end of the motor apart to find the centrifugal switch. I can see it. But the darn fan seems like it was molded in place after the motor was assembled. I tried to pry the fan off, but did not want to force the issue for fear that I will break it. But light was poor in the barn, very overcast and dark today. So I will take another look at it with the trouble light tomorrow,. I did run the motor for a brief period by giving the pully a spin as I flipped the switch to on. When I turned it off I could hear the centrifugal switch click. So I suppose it is open at run speeds and closed at low rpms.


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## Catpower

holtzdreher said:


> well the capacitor had no effect. So I took the end of the motor apart to find the centrifugal switch. I can see it. But the darn fan seems like it was molded in place after the motor was assembled. I tried to pry the fan off, but did not want to force the issue for fear that I will break it. But light was poor in the barn, very overcast and dark today. So I will take another look at it with the trouble light tomorrow,. I did run the motor for a brief period by giving the pully a spin as I flipped the switch to on. When I turned it off I could hear the centrifugal switch click. So I suppose it is open at run speeds and closed at low rpms.



See if you can steal your wife's nail file and bend it to so it will fit under the contacts, then carefully sand the contacts, or possibly a piece of sand paper glued to a stick, just something to get between the contacts and sand both sides

There is always the possibility the start windings are open, the wire to them burnt or they internally are open, but generally when that happens all the magic smoke comes out of the motor


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## holtzdreher

The magic smoke. Now that is an odd coincidence. When the thing went to crap, I was trying to make a German "Rauchermannchen" (Literally means Little smoker man) A Christmas decoration figure that serves as a novelty incense burner. The incense burns inside the body cavity and the smoke exits through the Mouth of the Character. In this case, A snowman with a pipe in his mouth. I was trying to drill the pipe stem before finish turning, so the smoke will actually exit through the bowl of the pipe. Usually the incense is pine, cedar or balsam. ( i make Christmas/holiday items that I donate to the local lions club and they sell them and use the money for their vision charities. )


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## Catpower

Guess it was it's time to give it up

I have been lucky I have a few Taiwanese/chinese motors and they are still running, a couple are about 35-40 years old

Now watch the next time I fire them up POOF LOL


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## Kenneth Meyer

Larry42 said:


> If you ask for a split phase motor, you won't get a cap start or cap run one as an option! It's a terminology thing.
> Too bad in the US we can't get 3 phase power in residential from the power company. In Germany you can. 3 phase has many advantages.
> If I have the option of 3 phase or single when buying a tool I'll always go for the 3 phase.
> For any of you guys w/o 3 phase you can home build a rotary phase converter for a lot cheaper than buying a commercially made one. Long ago I ran on one for 5 years before moving to a commercial location. They are simple to build. Required parts; a used 3phase motor, some big electrolytic capacitors, two switches and a box to put it all in (just incase you blow one of those big caps!) The caps provide the 3rd leg kick to start the motor spinning. The motor will be a generator making 3 phase. Your driven motors will only develop about 80% of fully rate power, but you rarely use the full rated power on most tools for other than a very short time. So don't pass up a great deal on a used tool just because it is 3 Phase. I suspect all the information for this setup is available online. I'm so damned old that there wasn't an internet when I made mine. Mine was based on an article in Fine Woodworking. I had asked an electrical engineer about it but he assured me that it wouldn't work. I didn't tell my machines that. Don't use this system on motors that require constant full power (dust collectors, pumps, etc..)
> Nice thing about 3 phase is instant reverse. Like when power tapping on my mill.
> Most of the new front load washing machines run on internally developed 3 phase so they can utilize electronic variable speed.
> My edgebander has an electronic frequency converter. It ups the normal 60 hz to 240 hz making the 3 phase trim motors run @ 14,000rpm (14,400 sincro.) You can up the speed of any 3 phase motor by just feeding it higher frequency, too much higher and it may fly apart! An older machine I had used a rotary freq changer, basically a motor generator set. You can also slow a motor the same way but cooling becomes an issue.


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## Kenneth Meyer

Larry42 said:


> If you ask for a split phase motor, you won't get a cap start or cap run one as an option! It's a terminology thing.
> Too bad in the US we can't get 3 phase power in residential from the power company. In Germany you can. 3 phase has many advantages.
> If I have the option of 3 phase or single when buying a tool I'll always go for the 3 phase.
> For any of you guys w/o 3 phase you can home build a rotary phase converter for a lot cheaper than buying a commercially made one. Long ago I ran on one for 5 years before moving to a commercial location. They are simple to build. Required parts; a used 3phase motor, some big electrolytic capacitors, two switches and a box to put it all in (just incase you blow one of those big caps!) The caps provide the 3rd leg kick to start the motor spinning. The motor will be a generator making 3 phase. Your driven motors will only develop about 80% of fully rate power, but you rarely use the full rated power on most tools for other than a very short time. So don't pass up a great deal on a used tool just because it is 3 Phase. I suspect all the information for this setup is available online. I'm so damned old that there wasn't an internet when I made mine. Mine was based on an article in Fine Woodworking. I had asked an electrical engineer about it but he assured me that it wouldn't work. I didn't tell my machines that. Don't use this system on motors that require constant full power (dust collectors, pumps, etc..)
> Nice thing about 3 phase is instant reverse. Like when power tapping on my mill.
> Most of the new front load washing machines run on internally developed 3 phase so they can utilize electronic variable speed.
> My edgebander has an electronic frequency converter. It ups the normal 60 hz to 240 hz making the 3 phase trim motors run @ 14,000rpm (14,400 sincro.) You can up the speed of any 3 phase motor by just feeding it higher frequency, too much higher and it may fly apart! An older machine I had used a rotary freq changer, basically a motor generator set. You can also slow a motor the same way but cooling becomes an issue.


I was hopping you can look up this video on YouTube it shows a guy making a PERPETUAL POWER GENERATOR with a car alternator . In every country but ours they use 220 volts so it seems he's using a 220 volt electric motor and a car alternator. But I need to know what wires did he twist together to make the 220 volt motor run and keep running. I have made a hydrogen device that makes enough hydrogen to run my Ford 460 motor that has a much larger than factor cam at 4700 rpms as long as I want to run it as it set in my house. So I need to find away to get 220 volts in this truck so it can drive down the road. And it is works as it does here at my house then we can all stop paying for gas cuz I can salve that problem. It takes a few others things to make this hydrogen but so far the things I have bought are from China and I am worried that it won't be long before 1 or a few of these few devices are going to start smoking and then proooof. So I can change a few things like a 220 volt motor and make it all work for only God knows how long but I need to get 220 volts in my truck. There a few videos on YouTube of guys taking apart starter motors and putting magnets in them and making some cool power supplies but I am not sure how long they will last running many hours while people drive around in there cars so I need a reliable source of power like 220 volts is best but I can also use 120 volts but just thought go big or go home kind of thinking. Got any ideas?


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