120v Vacuum Motor - RC Groups
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Oct 07, 2017, 10:43 PM
Registered User
Help!

120v Vacuum Motor


I have an old vacuum motor, and I was planning on doing something with it. Immediately, I came across the problem of "how exactly do you connect stuff like this to the wall socket?" Clearly I have never worked with wall outlets or AC current at all really. I was hoping someone could help me figure out how to wire this. I'm assuming it's just positive to hot and negative to neutral, but I'd rather ask for help than burn my house down. Also, there is a third wire on this but I'm not sure what it isn't for because this is a brushed motor. Please let me know if I have this right or if someone could give me a better explainatiin of what's going on that would be great. Also let me know if anyone has ideas that I could use this for. Thanks so much!
-Eric
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Oct 07, 2017, 11:25 PM
Wake up, feel pulse, be happy!
Piece's Avatar
That is a brushed DC motor. If you plug it straight into alternating current, you will have a terrifying joy buzzer.

Go back to your vacuum and find the rectifier circuit which originally went between the motor and the on/off switch (possibly packaged as one unit). That's what takes the incoming AC and converts it to DC for the motor. It's a common setup in appliances where a typical AC induction motor would spin too slowly and belting/gearing is impractical.

The third wire is a ground wire. It would be a good idea to connect it to a grounded outlet, but it's not functionally necessary.

As always, safety, caution, blah blah, pay attention and so on and so forth.
Oct 08, 2017, 12:26 AM
just look at it smokin'
z-matrix's Avatar
Quote:
Originally Posted by Piece
That is a brushed DC motor. If you plug it straight into alternating current, you will have a terrifying joy buzzer.

Go back to your vacuum and find the rectifier circuit which originally went between the motor and the on/off switch (possibly packaged as one unit). That's what takes the incoming AC and converts it to DC for the motor. It's a common setup in appliances where a typical AC induction motor would spin too slowly and belting/gearing is impractical.

The third wire is a ground wire. It would be a good idea to connect it to a grounded outlet, but it's not functionally necessary.

As always, safety, caution, blah blah, pay attention and so on and so forth.
Hello Piece!

A universal motor works from ac and dc too
there is a field winding that is connected in series with the armature (2 brushes) and the polarity of the voltage does not matter.
I have one too and it works from 240V AC and spins even at 5V DC
Efficiency is very low (30-40%?) and it is noisy, spins like crazy, eats 1200W.


Z
Oct 08, 2017, 09:01 AM
Registered User
pilotpete2's Avatar
Quote:
Originally Posted by Piece
That is a brushed DC motor. If you plug it straight into alternating current, you will have a terrifying joy buzzer.

Go back to your vacuum and find the rectifier circuit which originally went between the motor and the on/off switch (possibly packaged as one unit). That's what takes the incoming AC and converts it to DC for the motor. It's a common setup in appliances where a typical AC induction motor would spin too slowly and belting/gearing is impractical.

The third wire is a ground wire. It would be a good idea to connect it to a grounded outlet, but it's not functionally necessary.

As always, safety, caution, blah blah, pay attention and so on and so forth.
Definitly not a PM DC motor, but a universal field wound motor. Most homes have more of these motors tha any other type. Every corded hand held power tool and counter top kitchen appliance depend on these simple and practical devices.
Pete
Oct 08, 2017, 04:16 PM
I am a nice guy! Really!
Elove, you are playing with lethal voltage levels. Your questions indicate that you have no idea what you are doing. That is a sure combination to create a fatal accident. I suggest you do nothing with the motor until you learn a lot more about household power systems and their safe and proper use. You cannot possibly learn enough from a few responses on an R/C model forum.
Oct 10, 2017, 01:56 PM
Registered User
These motors are worthless, very high RPM and they run very hot. In fact all the power is used to turn the fan which is needed to cool the motor. It is just a side effect that it also creates a vacuum for cleaning.

If the armature has 9 or 12 poles it could be used to make a stator for a large outrunner. Even that would be useless as the slots are too small for good packing.

If you really want run it connect power to the large red and white wires.
Oct 14, 2017, 12:21 AM
Registered User
vollrathd's Avatar
FYI, these vacuum cleaner motors are universal type that will run on either AC or DC voltage. Big problem with them though. Never ever run them without the fan attached! If the fan is removed, there isn't much to limit the maximum RPM of the motor. It will wind up to far beyond its rated RPM, and destroy itself. It won't last 5 seconds.

That's why just about every power tool that uses this type of universal motor is also equipped with a fan. Both to cool the motor, and to limit maximum RPM under no load conditions.

We had this type of motor for closing power on the 2500 pound high voltage circuit breakers we made years ago. That motor was rated for 240 VAC and two horsepower. The motor gearbox design pulled up a pair of 700 pound springs through the gearbox. If the gearbox ever stripped a gear, there was never very much left of the motor.


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