AC or DC motor?

Hi,
I need a motor to put it to work on a clay mixer. Rotational speed of the blender must be adjustable between 1 and 24 rpm.
Using a gearbox I can reduce 1420 rpm of 1.5 hp single phase ac motor to 24 rpm but to reduce it up to 1 rpm I have to reduce motor speed without decrease of output power and torque of the gearbox. I have seen a video of a mixer in witch the operator just turns a switch to the right and left and easily that changes rotational speed of motor. any idea how can I do that? Should I use DC or AC motor to have a cheep,user friendly and simple system.
thanks.

I think,a AC motor grinder,one that is used in floor mill for grinding wet rice for making dosa or idle must be right choice for ur clay works..i think a light dimmer circuit can reduce the speed of motor..

Dear experts what u say...

A light dimmer is for light not for speed control.
But in near all power tools you have a proper speed control or you use one from home cooling fan.

That all incase you want to keep it simple.

but be a where i understand that money is all ways a problem, but please do not for get safety.
if you have clay you have water and water and electricity do not mix but do kill people.

Get yourself a 3 phase motor and then use a variable frequency drive to control the speed. VFD will give you full torque at what ever speed you need - within reason of course.

For an AC motor, the solution is a triac motor speed controller.
For a DC motor, the solution is a PWM DC motor speed controller.
Both are cheap and easily available.
What is the voltage of your main supply ?

I'm considering either 1 phase 220v 50 hz or a 3 phase motor and using it with 1 phase 220v 50hz supply.
Is it possible to use PWM with AC motors,if not why?
thanks

A triac AC motor speed controller uses a form of PWM, chopping up the AC waveform in the same manner as the DC PWM controller.

Single phase AC equipment is generally cheaper and more easily available.

For example, to control a single phase AC motor up to 2kW (2.7 hp)
(Copy and paste this in your browser address window):

http://www.ebay.co.uk/itm/2000W-Adjustable-50...ial_Automation_Control_ET&hash=item5d39c6a7f1

This is exactly the same kind of electronic circuit that controls the speed in a mains electric power tool. If you can buy a mains power tool speed controller, you can just plug it in and start working.

As Peter has said, keep all your electrical circuits dry, well proofed against water.

Hi

See the following article from velleman Kits
http://www.esr.co.uk/manuals/k2636.pdf

or consider this link as well
http://www.orientalmotor.com/products/ac-motors/msc-1.html

or this link might also be usefull to you
http://sg.renesas.com/media/applications/motor_control/triacdrive/TriacAppnote.pdf

or

http://www.8051projects.net/news-i188-single-...ac-motor-speed-controller-project-report.html

or

http://www.nxp.com/documents/application_note/APPCHP3.pdf

or

For in depth explanations see the following

http://www.ab.com/support/abdrives/documentation/fb/1024.pdf

Finally for 3 phase motor control see this link

http://cache.freescale.com/files/dsp/doc/app_note/AN1958.pdf

Not altogether correct Peter they can be used for motor control see below for link that explains this in more detail

http://www.mouser.com/catalog/specsheets/stevalill004v1.pdf

For DC motor speed controll see the following
http://www.hitex.com/fileadmin/img/download/B...PID_Control_With_The_Infineon_C167_Family.pdf

or you could use for dc motor control HIP4080AIP "Interesting !" or if you like one of the first projects I put together quite some time ago which you can re apply to DC motor control with code pcb layouts etc plus digital readout

By the way this includes memory for storing last set value and recalling last set value i wrote a small bit of VB code for rapid application development so I could work out how to move up the scale and down the scale which I used VB6 for but its all there for you if you want to use it (feel free)

Its original intention was for dimming interior lights in cars ideally suited for these long vehicles for the show offs You know the cars I mean, those long things that look like sausages you can drink in and get very drunk in the rear of the vehicle , normally driven by chauffeurs , the uh bald headed type “Britain’s well ard men, you know well ard !! “ the drivers of these vehicles typically wear huge rings and lots of metal chains around there necks and have to have a kidbney belt to stand up straight when they get out of the car due to the weight of the gold , They are a bit like Rocky blab alot boa without the hair The Long Ford’s etc they use for weddings but alas hum ha no interest was shown typical !! I’m really thoroughly jarred off




Any way heres the link

http://www.harrington.force9.co.uk/Projects/LightsController/LightsController.htm

Hi;
Thank you for sharing all these . I'm new on this area but your post is quite helpful.
thanks again.

Welcome Hadi