How To Make a Variable Speed Control From Scratch

[MJS]

Hi Everyone,

New to the forum and new to electronics.

I have a project idea that I need help with right from scratch.

Im looking to design, source parts, create and build myself
a variable speed control for a 240volt AC motor. Something that
starts in full speed for a few mins then falls back to the
set speed on the speed control.

Some things it needs.

1. Great torque at low speeds
2. Actually runs motor at full speed
3. No problems up to 2000 watts
4. Plug for motor and power point.
5. 240volt 10Amp motor

I figure it has to be as simple as possible for me to build
it and for reliability. This thing needs to last forever

This is something every similar to what I would like to do.
http://www.jaycar.com.au/productView.asp?ID=KC5478

Any help will be appreciated.

Basically, where do I start and what is the best method to do this?

Thanks,

Michael

 

[duke37]

I think this is well beyond a beginner, it is well beyond me.

I suggest that you first of all find the motor type and its characteristics such as resistance, inductance and leakage inductance.

You will need to protect your semiconductors with snubbers and will likely blow several until you get things right.

Are there not commercial motor drives which would suit you? Lathes are now sold with variable speed motors rather than multiple gears. If you go this route, you will need the control signal characteristics to do the program you want.

 

[DaveyD]

I agree with duke you would be better off buying a driver. If your panning of running this from a standard mains it's quite probable that you would keep tripping your fuse with 'great' torque. More over 240Vrms @ 10A = 2400W Uk plugs are normally limited to 3000W. Say for instance you Use PWM, you wouldn't be able to obtain the torque you need.