Small Motor Issues for Tumbler, Need Electrical advise

nevanevan

nevanevan

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I have a 1/4 hp motor from an old furnace blower that has been powering my stainless tumbler for some time. The issue is that there is way to much heat buildup going on even with a step up pulley system.

I recently acquired a motor from an old front load washer that seems to be in great shape. It says that it is a DC120volt FHP motor, see picture below.

20150221_103924.jpg


I am under the impression that I cannot hook up a rheostat to an A/C motor as it needs to have full amperage to operate, however, my question is, can I safely hook up this motor to a variable switch rheostat to control the RPM? The video below shows that it is going way to fast to tumble brass. Maybe turn your volume down in advance as it came out loud on my computer.

Thanks for the help in advance
Evan
 
first off the video doesn't work so I cant see what you have !!!washing machine motor or the fan motor will not work not made for that use you need something that runs slower, you need to slow the gear ratio down for example put a small pulley on the motor and a big one on the tumbler then the ratio slows down. neither motor will work on a variable speed the motors are not made that way the fan motor is 1725, rpm that's way to fast for what you want , not sure of the washing machine motor is I do furnace repair that's how I no this .look on youtube theres good info on how to make your own tumblers I looked at it one time I was going too make one . if you have any questions pm me and ill try to help >>>> hound2013
 
hooking up a rheostat is not the only thing you need to slow down the RPM of the motor, so your best option is don't try it...the tread mill idea is probably the best way to go, or just changing the ratio of the pulleys.
 
I'm thinking of building a tumbler as well, there are lots of homemade versions available. I like the idea of the treadmill motor, also using a power window motor on a power supply seems to work pretty good. As soon as it warms up outside I'll go in the garage and see what I can fab together.
 
FromTheNorth said:
hooking up a rheostat is not the only thing you need to slow down the RPM of the motor, so your best option is don't try it...the tread mill idea is probably the best way to go, or just changing the ratio of the pulleys.
Click to expand...
Why wouldn't a reostat work for a D/C, your post failed to explain this.

first off the video doesn't work so I cant see what you have !!!washing machine motor or the fan motor will not work not made for that use you need something that runs slower, you need to slow the gear ratio down for example put a small pulley on the motor and a big one on the tumbler then the ratio slows down. neither motor will work on a variable speed the motors are not made that way the fan motor is 1725, rpm that's way to fast for what you want , not sure of the washing machine motor is I do furnace repair that's how I no this .look on youtube theres good info on how to make your own tumblers I looked at it one time I was going too make one . if you have any questions pm me and ill try to help >>>> hound2013
Click to expand...
I am aware that the washing machine motor is a DC unit. I already have the furnace fan motor working at 1725 rpm going to an 8" pulley which reduces the rpm nicely on my 12" tumbler. The problem is this fan motor develops way to much heat, as I understand that A/C motors are not nearly as efficient as a D/C.
 
To vary the speed of an AC motor you must vary the frequency (60 Hz). If you try to reduce the voltage it will over heat.

You can vary the seed of a DC motor by varying the voltage.
 
the rheostat is only going to changing the voltage, thats not what you want to happen, you need to change the armature current and thats gong to take a few more components to do that...i could right up a whole page on it but unless your an electrician or some other, its not going to make a whole lot of sense. not saying that your not going to get it, its i have a hard time myself some times understanding this crap and my mind might blow up trying to figure it all out again.
 
Varmit said:
To vary the speed of an AC motor you must vary the frequency (60 Hz). If you try to reduce the voltage it will over heat.

You can vary the seed of a DC motor by varying the voltage.
Click to expand...

Can anybody confirm from the picture that I posted that this is a DC motor. Do they make DC motors with compact power invertors that are integral to the motor assembly
20150221_103924.jpg
 
dc motor, most of them have built in power inverters, the one you have posted has a built in one. that said, most motors today that you come across in retail stores like TSE(ontario), UFA(alberta) are all DC motors, you don't see many AC ones only if its for a very specific purpose, they are more commonly found in manufacturing plants.
 
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Gentlemen this is what I have done for the past 45 years of my life...........that is not a DC motor as it clearly states 50/60 hz The DC is just part of the spec number. The reason you can't slow a lot of motors with a rheostat is because they have an internal mechanical centrifugal switch which brings in the start winding until the motor reaches approx. 60% of rated speed and then removes it from the line. You can use a rheostat on any shaded pole motor and reduce the winding voltage which will reduce the speed as long as the load is constant. The torque of the motor and hence the HP will reduce by the square of the voltage reduced. Shaded pole motors are commonly found in furnace fans, range hoods and bath fans and the like. Range hood and bath fans have enough torque to run a tumbler if the gear reduction is great enough to work at the correct speed. The easiest method of running a tumbler is to use an automotive heater fan and a battery charger or any variable 12 volt DC power supply.
Princess auto has no end of cheap little motors and little gear box/ motor combos. Do not use a power window motor as they are rated for intermittent use only and will most certainly burn out in minutes. They are relatively high torque, high current and have about a 5% duty cycle.

Most DC motors do NOT have built in power inverters and neither do AC motors.........not sure where this fallacy came from. And most certainly the motor nameplate you have posted has no such thing inside, it is an ordinary everyday European made fractional HP single phase motor.
 
I have a motor from a discarded treadmill that I want to use in a DIY tumbler build. It seems to me that it rotates too quickly as is, does anyone know the optimum rpm rate?
I was told that a potentiometer was the electrical devise I need to slow it down properly. Can anyone confirm this?
 
A potentiometer on all my natural vents at work just count how many revolutions the shaft has turned to show what percentage they are open on the control box. The feed mill also has them to count out how much grain has gone thru the mill. So it would tell you how fast the motor is running not control the speed.
 
c-fbmi said:
Gentlemen this is what I have done for the past 45 years of my life...........that is not a DC motor as it clearly states 50/60 hz The DC is just part of the spec number. The reason you can't slow a lot of motors with a rheostat is because they have an internal mechanical centrifugal switch which brings in the start winding until the motor reaches approx. 60% of rated speed and then removes it from the line. You can use a rheostat on any shaded pole motor and reduce the winding voltage which will reduce the speed as long as the load is constant. The torque of the motor and hence the HP will reduce by the square of the voltage reduced. Shaded pole motors are commonly found in furnace fans, range hoods and bath fans and the like. Range hood and bath fans have enough torque to run a tumbler if the gear reduction is great enough to work at the correct speed. The easiest method of running a tumbler is to use an automotive heater fan and a battery charger or any variable 12 volt DC power supply.
Princess auto has no end of cheap little motors and little gear box/ motor combos. Do not use a power window motor as they are rated for intermittent use only and will most certainly burn out in minutes. They are relatively high torque, high current and have about a 5% duty cycle.

Most DC motors do NOT have built in power inverters and neither do AC motors.........not sure where this fallacy came from. And most certainly the motor nameplate you have posted has no such thing inside, it is an ordinary everyday European made fractional HP single phase motor.
Click to expand...

I am also in the industry, and this is correct. Also, not sure what a "built in power inverter" would be exactly but a DC motor-unit that runs on an AC source would require a rectifier built in, not an inverter. You would need a variable frequency drive to slow down the AC motor you have, or you would have to build a pulley system to slow it down enough, if you even could. Anyway, your best solution is what is posted above, choose the right motor and power source for the job.
 
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It was free, and I'm cheap looking for different options. Thanks so much for all the advise offered. I hope some other less knowledgeable people learned something from this thread.

Evan
 
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