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Lowering AC Motor RPM's

MickeyB

Jun 13, 2023
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I am a sculptor and would like to use some common small household electronics in my work, such as:

Razors
Foot Massagers
Mixers
Electric Knives
Slicers
Pencil Sharpeners
Tooth Brush
Shoe Polisher

However, I want to be able to lower the RPMs of each item down to maybe 3-10 RPMs. What type of hardware interface would work? i.e. Router controller, motor controller, variable frequency driver, Motor Rheostat. I ‘am old school, so if you know any Ebay or Amazon products let me know. thanks
 

Bluejets

Oct 5, 2014
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The only AC motors of this small size (I Imagine small as no details on the motors given) that can be speed controlled are series type motors.
i.e. brush type however, your required low end speed of 3 to 10 rpm would not be possible.
One normally uses phase control via thyristors which may lower the speed top around 20% (maybe) all-be-it with substantial loss of torque.
However, you would be "playing" with mains voltages and not recommended.

Any DC motor (toothbrush for example....low voltage) can be speed reduced via a two bob pwm control from Ebay etc. but again, with substantial loss of torque.

There are dc motor /gearbox unit available online fairly cheap in a variety of sizes right down to miniature model servo size, control speed via pwm again, however in this instance, torque is maintained via the gearbox.
Output speeds available in a variety of ratios.
Any remote control type servo can be modified as a motor /gearbox if you want to go this path.
They have output control horn and mountings already as part of their design which would made adapting to your projects more amateur friendly.
 
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bidrohini

Feb 1, 2023
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You can use an Arduino and a motor driver like the L298. The Arduino UNO has some PWM pins. If you connect them to the Enable pins of the L298 and program the Arduino accordingly, you will be able to control the speed of your motors.

 

Minder

Apr 24, 2015
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You can use an Arduino and a motor driver like the L298. The Arduino UNO has some PWM pins. If you connect them to the Enable pins of the L298 and program the Arduino accordingly, you will be able to control the speed of your motors.

The L298 is totally unsuitable for AC (mains powered) motors, which is what the OP appears to be using.
Also the L298 is only a DC H-bridge low voltage controller.
 

Delta Prime

Jul 29, 2020
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Is it me or is the LED display on that amazon speed controller upside down!
All things being equal, the seven segment LED display is slightly askew by two arc seconds.
photo_1690242153382.png

It all depends on how you "eyeball" it. :p
 

Delta Prime

Jul 29, 2020
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Same here in the Southern hemisphere..........
Then again, have to expect that kind of thing with 2 bob gear
What hemisphere the world is flat!
And leave Bob out of this!
I'm pretty sure he's a nice guy whoever he is. :rolleyes:
 

73's de Edd

Aug 21, 2015
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Thir Kelly . . . . . . . . . with your ¿ defective ? eye
Of 3 different found manufacturers seen, that are cloning units, the central caret symbol appears differently . . positioned . . at top or bottom . . . between the 3 units.

ALSO . . . . . as you or I would typically be using a unit . . . . with its decimal points utilized . . . . that positional error would be glaringly noted.

HOWEVER . . . . . since they are not powering up and using the decimal points . . . . all is being well if they " accidentally " happen to be located "erroneously " at the top of the display.
DEMONSTRATION . . . . . a la Video

Thaaaaaaaaaaaaaaaassit . . . . . .

73's de Edd . . . . .


To be honest I don't know and haven't figured yet what 'TBH' and 'IDK' . . . . . that I see people using . . .even mean.
 

kellys_eye

Jun 25, 2010
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Thir Kelly . . . . . . . . . with your ¿ defective ? eye

It was 'tongue-in-cheek' really..... I'm aware that a 7-segment display is the same regardless of its orientation (up/down) if you ignore the d.p. In a world of 'aesthetics' you'd think the manufacturers would be aware of 'polarity'. But, then again, we're talking China here.......
 

Delta Prime

Jul 29, 2020
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Yes we are talking cheap China here but it was based on the product below that I use in my work Laboratory it's the only reason why I suggested it cuz I opened up the cheap China rip off. Same components rearranged are the same internal and my superiors we're impressed at the same time they cringed because China is safe from intellectual property but if you don't have the financial resources my suggestion would do nicely. As opposed to the suggestions or lack thereof to the TS inquiry. It's easy and convenient enough to be a critic while observing in the nosebleed seats.
1690312259465.png
 

Delta Prime

Jul 29, 2020
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How "coincidental" is it that your . . . . . .A . . .H . . .E . . .M . . . . . . ." unit" at your workplace . . . . happens to share IDENTICAL serial numbers ? with this specific unit, that is located in Ft Wayne Indiana . . . . . . long haul from LA.

H&W Machine Works
2119 Meyer Road Fort Wayne, IN 46803
It's part of their advertisement if you search a little more that unit is over $2,000.
And sorry I cannot show you the purchase order that is the property of California institute of technology. photo_1686890275166.png
 
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