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How to Slow Down a 240Vac Electric Motor? Answered

I bought a small, industrial motor and want to safely slow it's rpm. 
Does anyone have any advice as how to best go about this? 
I've looked into gearing and found this to be quite complex but understand that an alternative option may be to change the voltage received by the motor? 


Thank you for any help you provide

Discussions

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Irritable_Badger
Irritable_Badger

4 months ago

It’s worth noting that your motor is designed for intermittent use, not sustained operation. If you slow it down electrically it’s going to run hotter than designed so the duty cycle is going to be reduced. You’ll have to adjust your design to suit the new duty cycle.

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AryH2
AryH2

Reply 2 months ago

How can I easily determine if a motor is suitable for continuous or intermittent use? Is a washing machine motor for continuous use? What about lathe motor and bench drill motor?

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Irritable_Badger
Irritable_Badger

4 months ago

Use pulleys. There’s no reason to get into actual gearing or complex frequency modulation. The nice things about pulleys is they are inexpensive, available everywhere with belts of any size and very forgiving of misalignments.

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pmpottery
pmpottery

4 months ago

I have a washing machine motor that I want to slow down and make the rpm adjustable from 0-300, instead of the three options listed on the side of the motor. I have all of the washing machine controls and a controller from a band saw(and the band saw motor). The plugs that go to the controllers on the washing machine have the same kind of connections as the band saw controller, could I just use the band saw controller(which has an adjustable dial) in place of the washing machine controller....I know the power on the band saw motor uses a lot less power(amps) than the washing machine motor (also has a capacitor). I don't want to burn any of the parts up...I think that the capacitor makes it so that I can't do this.. because the capacitor won't power the mother with lower Amos, or the band saw controller will get friend....any help would be greatly appreciated.

IMG_20191116_173142_HHT.jpgIMG_20191116_173159.jpg
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levim39
levim39

1 year ago

how to make speed controler of a motor

1
liquidhandwash
liquidhandwash

4 years ago

You have only really 2 options for that motor. Gear it down, or use a speed controller. Silicon chip magazine did a kit for a speed controller last year, if you want to build it yourself. You cant just just use any speed controller for that type of motor. Yours is and induction motor so you have to control the frequency of the AC . A universal motor has brushes inside it and can be controlled by changing the voltage, and the speed controller for that type of motor is much cheaper.

http://www.altronics.com.au/p/k6032-1.5kw-full-induction-motor-speed-controller-kit/

http://www.siliconchip.com.au/Issue/2014/March/230V-10A+Speed+Controller+For+Universal+Motors%2C+Pt.2

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steveastrouk
steveastrouk

Answer 4 years ago

Interesting links. Thanks.

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Downunder35m
Downunder35m

4 years ago

From what's there it is a motor that requires a capacitor to run, next to impossible to slow these down.
If it starts and runs without a capacitor you can tr a dimmer that can handle inductiv loads - if you are lucky you find one at Bunnings but lately I saw only "fan controllers" which are useless.
You can always run them with a frequency motor converter but they mostly come for three pahse motors to connect them to single phase use with speed and break control.

Might be better to salvage an old treadmill to get a strong motor with speed control here in AU...

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Josehf Murchison
Josehf Murchison

4 years ago

Change the AC frequency.

AC motors work by the AC current changing the magnetic pols in your case 50 cycles if you change that to 40 cycles the pols change slower and the motor turns slower. Just watch the current if the current stays the same you are OK, if the current goes up the motor will burn out. The only other way is a current limiting circuit but that is load regulated.

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Magicyman
Magicyman

4 years ago

Reducing the voltage going into your motor should slow it down, however. An AC motor may not like that, some go bad, some will shut off, but some do work fine, so reduce voltage at your own risk :)

If you still wish to decrease the voltage you'll need a potentiometer of some sort, make sure it's rated to the voltage that it will be receiving, a good quick DIY potentiometer might be a dimmable light switch, but again, make sure it can handle the voltage. A quick google search will give you a far better tutorial on how to hook one up then I can.

Hope this helps!