single phase AC motors

[Hughman]

I need a primer on small motors: how to check function, determining which wire does what, grounding 2-wire units...

I even need to learn the vocabulary. [img]redface.gif[/img]

What is the standard reference?

[Hughman]

I need a primer on small motors: how to check function, determining which wire does what, grounding 2-wire units...

I even need to learn the vocabulary. [img]redface.gif[/img]

What is the standard reference?

[Hughman]

I need a primer on small motors: how to check function, determining which wire does what, grounding 2-wire units...

I even need to learn the vocabulary. [img]redface.gif[/img]

What is the standard reference?

[Ross M]

I think Audel's "Electric Motors" can get you a long way down the road. It is just under $20 at Amazon.

Ross

[Ross M]

I think Audel's "Electric Motors" can get you a long way down the road. It is just under $20 at Amazon.

Ross

[Ross M]

I think Audel's "Electric Motors" can get you a long way down the road. It is just under $20 at Amazon.

Ross

[pipefitter]

Grounding 2 wire units is done by chassis ground or the green screw in or on the housing.
Most things that go wrong with single phase motors that aren't toast is,Starting capacitors,centrifugal starting switch,and bearings. Most common bearing sizes for motors with 1/2" shaft is 6202 5/8ths shaft is 6203, 3/4" shaft is 6304.Anything else that can go wrong with modern electric motors would be the windings.If those are shorted the motor is pretty much disposeable becuase a new one is cheaper than a rewind or the lack of warranty makes it false economy to do so unless it is special aps such as a long shaft motor that drives a multistage well pump or an obsolete bolt pattern (rare). WHen a start capacitor is bad the motor will hum but will very slowly turn the armature as if it wants to start. You can spin the shaft on a bad capacitor motor by winding a string on it and pull starting it.With the centrifugal start switch it operates a set of contacts or points.Always check the switch for proper adjustment and contact. Also, I have made many service calls for ants getting into the points.I threatened to let a jar of them loose on every call I went on.
Note on the hum or buzz associated with a bad start capacitor motor is that a shorted motor will buzz too...just louder. You can get the books to check all the resistances of the circuitry and combinations but 9 out of 10 times,you can smell a burnt winding alot quicker than ohming one out.

As far as which wire does what...L1 and L2 are where the line voltage goes from the electrical source.The only other concern would be changing a motor over from 110 to 220v and that would have a schematic inside the access plate or cover. If not you would need to reference the manual for the color code .Some motors such as AO Smith all use the same wires for switching voltages.

Hughman,not sure if this is what you meant by vocabulary. What I have stated here is field talk and not from a book. This is the way it is stated if you are making a living at it. There is a broader range of motors and a higher techical sense for sure.Hope this helps

[ 12-13-2005, 01:44 AM: Message edited by: pipefitter ]

[pipefitter]

Grounding 2 wire units is done by chassis ground or the green screw in or on the housing.
Most things that go wrong with single phase motors that aren't toast is,Starting capacitors,centrifugal starting switch,and bearings. Most common bearing sizes for motors with 1/2" shaft is 6202 5/8ths shaft is 6203, 3/4" shaft is 6304.Anything else that can go wrong with modern electric motors would be the windings.If those are shorted the motor is pretty much disposeable becuase a new one is cheaper than a rewind or the lack of warranty makes it false economy to do so unless it is special aps such as a long shaft motor that drives a multistage well pump or an obsolete bolt pattern (rare). WHen a start capacitor is bad the motor will hum but will very slowly turn the armature as if it wants to start. You can spin the shaft on a bad capacitor motor by winding a string on it and pull starting it.With the centrifugal start switch it operates a set of contacts or points.Always check the switch for proper adjustment and contact. Also, I have made many service calls for ants getting into the points.I threatened to let a jar of them loose on every call I went on.
Note on the hum or buzz associated with a bad start capacitor motor is that a shorted motor will buzz too...just louder. You can get the books to check all the resistances of the circuitry and combinations but 9 out of 10 times,you can smell a burnt winding alot quicker than ohming one out.

As far as which wire does what...L1 and L2 are where the line voltage goes from the electrical source.The only other concern would be changing a motor over from 110 to 220v and that would have a schematic inside the access plate or cover. If not you would need to reference the manual for the color code .Some motors such as AO Smith all use the same wires for switching voltages.

Hughman,not sure if this is what you meant by vocabulary. What I have stated here is field talk and not from a book. This is the way it is stated if you are making a living at it. There is a broader range of motors and a higher techical sense for sure.Hope this helps

[ 12-13-2005, 01:44 AM: Message edited by: pipefitter ]

[pipefitter]

Grounding 2 wire units is done by chassis ground or the green screw in or on the housing.
Most things that go wrong with single phase motors that aren't toast is,Starting capacitors,centrifugal starting switch,and bearings. Most common bearing sizes for motors with 1/2" shaft is 6202 5/8ths shaft is 6203, 3/4" shaft is 6304.Anything else that can go wrong with modern electric motors would be the windings.If those are shorted the motor is pretty much disposeable becuase a new one is cheaper than a rewind or the lack of warranty makes it false economy to do so unless it is special aps such as a long shaft motor that drives a multistage well pump or an obsolete bolt pattern (rare). WHen a start capacitor is bad the motor will hum but will very slowly turn the armature as if it wants to start. You can spin the shaft on a bad capacitor motor by winding a string on it and pull starting it.With the centrifugal start switch it operates a set of contacts or points.Always check the switch for proper adjustment and contact. Also, I have made many service calls for ants getting into the points.I threatened to let a jar of them loose on every call I went on.
Note on the hum or buzz associated with a bad start capacitor motor is that a shorted motor will buzz too...just louder. You can get the books to check all the resistances of the circuitry and combinations but 9 out of 10 times,you can smell a burnt winding alot quicker than ohming one out.

As far as which wire does what...L1 and L2 are where the line voltage goes from the electrical source.The only other concern would be changing a motor over from 110 to 220v and that would have a schematic inside the access plate or cover. If not you would need to reference the manual for the color code .Some motors such as AO Smith all use the same wires for switching voltages.

Hughman,not sure if this is what you meant by vocabulary. What I have stated here is field talk and not from a book. This is the way it is stated if you are making a living at it. There is a broader range of motors and a higher techical sense for sure.Hope this helps

[ 12-13-2005, 01:44 AM: Message edited by: pipefitter ]

[Hughman]

Thanks, Ross, I'll get one [img]smile.gif[/img]

Thank you also, Pipefitter. I tried grounding one of my motors this way, but it trips the GFI every time. I wonder if this particular motor has a short to the case, but I don't know how to check it. These motors are running 50-year old drill presses, lathes, table saws, etc.

Running grounds to all this iron is part of a dust collection project using plastic hose.

The schematic panels have long gone to dust. Some of the motors have 4 terminals labled 1 thru 5, with one terminal labled with 2 numbers.

One of the cap start motors had a capacator filled with (I suspect) a toxic liquid (PCB's?) - It smoked, so I removed it, leaving the wires unconnected. I hand start this one. I might be able to find a replacement at Grainger.

As you can see, I have a laundry list of issues with these old relics. Replacing them all would be expensive! Besides, the extra weight of these old types stretches the drive belts!

I enjoyed reading your website, Pipefitter [img]smile.gif[/img]

[Hughman]

Thanks, Ross, I'll get one [img]smile.gif[/img]

Thank you also, Pipefitter. I tried grounding one of my motors this way, but it trips the GFI every time. I wonder if this particular motor has a short to the case, but I don't know how to check it. These motors are running 50-year old drill presses, lathes, table saws, etc.

Running grounds to all this iron is part of a dust collection project using plastic hose.

The schematic panels have long gone to dust. Some of the motors have 4 terminals labled 1 thru 5, with one terminal labled with 2 numbers.

One of the cap start motors had a capacator filled with (I suspect) a toxic liquid (PCB's?) - It smoked, so I removed it, leaving the wires unconnected. I hand start this one. I might be able to find a replacement at Grainger.

As you can see, I have a laundry list of issues with these old relics. Replacing them all would be expensive! Besides, the extra weight of these old types stretches the drive belts!

I enjoyed reading your website, Pipefitter [img]smile.gif[/img]

[Hughman]

Thanks, Ross, I'll get one [img]smile.gif[/img]

Thank you also, Pipefitter. I tried grounding one of my motors this way, but it trips the GFI every time. I wonder if this particular motor has a short to the case, but I don't know how to check it. These motors are running 50-year old drill presses, lathes, table saws, etc.

Running grounds to all this iron is part of a dust collection project using plastic hose.

The schematic panels have long gone to dust. Some of the motors have 4 terminals labled 1 thru 5, with one terminal labled with 2 numbers.

One of the cap start motors had a capacator filled with (I suspect) a toxic liquid (PCB's?) - It smoked, so I removed it, leaving the wires unconnected. I hand start this one. I might be able to find a replacement at Grainger.

As you can see, I have a laundry list of issues with these old relics. Replacing them all would be expensive! Besides, the extra weight of these old types stretches the drive belts!

I enjoyed reading your website, Pipefitter [img]smile.gif[/img]

[pipefitter]

Usually on older motors,they had a cloth type insulation on the wires inside the motor that would get brittle and fall apart. Sometimes they will get a strand of wire hitting the case. Blowing capacitors is a good indication of a short in the start winding of the motor.With older motors you wont find an "as good" replacement and I would get those rewound. One thing with a rewind is that you will get solid copper winding.The older motors were "true hp rated" and run alot cooler,quieter etc.Grainger is a good source for sure. I'm just not real crazy about dayton motors.On the grounding problem you can take a voltage tester and check the chassis for feedback voltage but tripping the breaker is a sure sign of a short.When starting motors with centrifugal starting switches,listen for it to click out when turning the motor off.The disk types with the weights can have broken springs/spring bands,etc.Also you can feel for hot spots on the case.The older motors should run for quite awhile before getting very warm. The newer motors run quite hotter.
Good luck Hughman and thanks for the compliment.

[pipefitter]

Usually on older motors,they had a cloth type insulation on the wires inside the motor that would get brittle and fall apart. Sometimes they will get a strand of wire hitting the case. Blowing capacitors is a good indication of a short in the start winding of the motor.With older motors you wont find an "as good" replacement and I would get those rewound. One thing with a rewind is that you will get solid copper winding.The older motors were "true hp rated" and run alot cooler,quieter etc.Grainger is a good source for sure. I'm just not real crazy about dayton motors.On the grounding problem you can take a voltage tester and check the chassis for feedback voltage but tripping the breaker is a sure sign of a short.When starting motors with centrifugal starting switches,listen for it to click out when turning the motor off.The disk types with the weights can have broken springs/spring bands,etc.Also you can feel for hot spots on the case.The older motors should run for quite awhile before getting very warm. The newer motors run quite hotter.
Good luck Hughman and thanks for the compliment.

[pipefitter]

Usually on older motors,they had a cloth type insulation on the wires inside the motor that would get brittle and fall apart. Sometimes they will get a strand of wire hitting the case. Blowing capacitors is a good indication of a short in the start winding of the motor.With older motors you wont find an "as good" replacement and I would get those rewound. One thing with a rewind is that you will get solid copper winding.The older motors were "true hp rated" and run alot cooler,quieter etc.Grainger is a good source for sure. I'm just not real crazy about dayton motors.On the grounding problem you can take a voltage tester and check the chassis for feedback voltage but tripping the breaker is a sure sign of a short.When starting motors with centrifugal starting switches,listen for it to click out when turning the motor off.The disk types with the weights can have broken springs/spring bands,etc.Also you can feel for hot spots on the case.The older motors should run for quite awhile before getting very warm. The newer motors run quite hotter.
Good luck Hughman and thanks for the compliment.

[BirchBark]

Hughman,

Check here: http://www.owwm.com/FAQ/
3/4 of the way down the page there's a section called "Motors and Electricity".

Chris

[BirchBark]

Hughman,

Check here: http://www.owwm.com/FAQ/
3/4 of the way down the page there's a section called "Motors and Electricity".

Chris

[BirchBark]

Hughman,

Check here: http://www.owwm.com/FAQ/
3/4 of the way down the page there's a section called "Motors and Electricity".

Chris

[Hughman]

Thanks again Pipefitter, You must have already checked out this pile of motors! Ya pretty much nailed what I'm dealing with....
How much of a pain is rewinding?


Birchbark, thanks for the link! OWWM is a great resourse. I'll have to download those PDF's on a faster machine, tho.

[Hughman]

Thanks again Pipefitter, You must have already checked out this pile of motors! Ya pretty much nailed what I'm dealing with....
How much of a pain is rewinding?


Birchbark, thanks for the link! OWWM is a great resourse. I'll have to download those PDF's on a faster machine, tho.

[Hughman]

Thanks again Pipefitter, You must have already checked out this pile of motors! Ya pretty much nailed what I'm dealing with....
How much of a pain is rewinding?


Birchbark, thanks for the link! OWWM is a great resourse. I'll have to download those PDF's on a faster machine, tho.

[hikingchrs]

The steps for rewinding a motor are
1. Disasemble motor
2. remove wire from stator (usually done by burning out all the varnish that holds windings in place, then cutting wires at one end with a air chisel then prying them out with a screw driver).
3. make new coils with coil winding machine
4. sandblast stator
5. place coils in stator
6. dunk stator in varnish
7. bake stator in oven to harden varnish
8. paint and reasemble
This should probaly left to the pros I worked in a motor shop for a summer steps 3 and 5 are still a mystery to me.
Chris

[hikingchrs]

The steps for rewinding a motor are
1. Disasemble motor
2. remove wire from stator (usually done by burning out all the varnish that holds windings in place, then cutting wires at one end with a air chisel then prying them out with a screw driver).
3. make new coils with coil winding machine
4. sandblast stator
5. place coils in stator
6. dunk stator in varnish
7. bake stator in oven to harden varnish
8. paint and reasemble
This should probaly left to the pros I worked in a motor shop for a summer steps 3 and 5 are still a mystery to me.
Chris

[hikingchrs]

The steps for rewinding a motor are
1. Disasemble motor
2. remove wire from stator (usually done by burning out all the varnish that holds windings in place, then cutting wires at one end with a air chisel then prying them out with a screw driver).
3. make new coils with coil winding machine
4. sandblast stator
5. place coils in stator
6. dunk stator in varnish
7. bake stator in oven to harden varnish
8. paint and reasemble
This should probaly left to the pros I worked in a motor shop for a summer steps 3 and 5 are still a mystery to me.
Chris

[pipefitter]

Rewinding an electric motor properly is one of the dying arts. You need special equipment and dies to do this with.Armature/core clearances are critical.It isnt too expensive to have it done. Here in Tampa it costs about 1/2 to 2/3rds what a new motor costs. I would look for a shop thats been in business the longest with a veteran motor man.
I worked on electric motors for 20 yrs,Hughman.All makes and models from very small to very large. Still have some of the old cast iron housed franklin motors I rebuilt.I have some old pump customers that would need these motors because a pump will outlive 2-3 motors.I used to be able to diagnose one upon walking up to it by the sound it was making or not making lol...I dont work in that field anymore but some of the old timers refuse to let anyone else work on their stuff so I do a call once in awhile to the special customers that I have had for all that time. I just dont want them to get the shaft. (NPI). Some are on fixed incomes and with other companies charging 90.00 for a service call,I just cant let them go thru that getting taken advantage of. Old customers end up being old friends,if you know what I mean.

You are correct hikngchris.And thats where the art is in knowing how many turns to wind,etc.

[ 12-13-2005, 11:36 PM: Message edited by: pipefitter ]

[pipefitter]

Rewinding an electric motor properly is one of the dying arts. You need special equipment and dies to do this with.Armature/core clearances are critical.It isnt too expensive to have it done. Here in Tampa it costs about 1/2 to 2/3rds what a new motor costs. I would look for a shop thats been in business the longest with a veteran motor man.
I worked on electric motors for 20 yrs,Hughman.All makes and models from very small to very large. Still have some of the old cast iron housed franklin motors I rebuilt.I have some old pump customers that would need these motors because a pump will outlive 2-3 motors.I used to be able to diagnose one upon walking up to it by the sound it was making or not making lol...I dont work in that field anymore but some of the old timers refuse to let anyone else work on their stuff so I do a call once in awhile to the special customers that I have had for all that time. I just dont want them to get the shaft. (NPI). Some are on fixed incomes and with other companies charging 90.00 for a service call,I just cant let them go thru that getting taken advantage of. Old customers end up being old friends,if you know what I mean.

You are correct hikngchris.And thats where the art is in knowing how many turns to wind,etc.

[ 12-13-2005, 11:36 PM: Message edited by: pipefitter ]

[pipefitter]

Rewinding an electric motor properly is one of the dying arts. You need special equipment and dies to do this with.Armature/core clearances are critical.It isnt too expensive to have it done. Here in Tampa it costs about 1/2 to 2/3rds what a new motor costs. I would look for a shop thats been in business the longest with a veteran motor man.
I worked on electric motors for 20 yrs,Hughman.All makes and models from very small to very large. Still have some of the old cast iron housed franklin motors I rebuilt.I have some old pump customers that would need these motors because a pump will outlive 2-3 motors.I used to be able to diagnose one upon walking up to it by the sound it was making or not making lol...I dont work in that field anymore but some of the old timers refuse to let anyone else work on their stuff so I do a call once in awhile to the special customers that I have had for all that time. I just dont want them to get the shaft. (NPI). Some are on fixed incomes and with other companies charging 90.00 for a service call,I just cant let them go thru that getting taken advantage of. Old customers end up being old friends,if you know what I mean.

You are correct hikngchris.And thats where the art is in knowing how many turns to wind,etc.

[ 12-13-2005, 11:36 PM: Message edited by: pipefitter ]