Thread: variable speed

Bob, Could you describe your current set up?

Variable speed can be electronic or mechanical. It can be done to anything that has a motor......for a price, its only a matter of money

In most cases the existing motor cannot be changed to variable speed.

You usually have to change the motor and switch gear to be able to use variable speed.

Seeing as Jim is too modest to say it, have a look here http://www.cws.au.com/cgi/index.cgi/..._id=1107144886

I think Jim's talkin' about you can't change the motor itself, if it's a single speed motor.....
But you can rig a series of pulleys on the motor and the lathe, to accomplish different speeds.

Originally Posted by robyn2839

is it possible to convert the motor on my lathe to variable speed? or do i have to go and buy the complete unit. bob

Hi Robyn.

If you are looking for electronic infinite variable speed on your lathe you require a three phase motor and electronic speed unit including stop / start and speed knob.
The electronic speed unit converts the power back to your normal single phase for home workshop use.
Whole system is not cheap, adapting your existing motor pulley can present problems but if all is achieved, then you enter a new world of woodturning.

Cheers Woodfast Aust
www.woodfast.com.au

thanks for that ,it was to change my beaver with pulleys ,to a full electronic variable, will have to start saving.(nothing worse than changing belts and pulleys just to drill a hole then change back up). bob

A little bit further afield but these guy's seem to have all that it needs to do the job in hand.
I'm sure someone in Oz does similar.

These guys sell single phase to 3phase variable speed controllers.
If thats what you want.
They are a lot closer to you too.
http://www.automationdirect.com.au/

Poloris

Originally Posted by Jim Carroll

In most cases the existing motor cannot be changed to variable speed.

You usually have to change the motor and switch gear to be able to use variable speed.

I had a look at the motor indicated by . Can't tell from the photo and the specs are not listed. What is it that makes it regulable with a simple potentiometer? If Robin's motor just happens to be of the same type (we do not know this) just buying a potentiometer will suffice. (Last time I dabbled with this stuff it would have been a rheostat... no semiconductors yet!)

Originally Posted by Frank&Earnest

I had a look at the motor indicated by . Can't tell from the photo and the specs are not listed. What is it that makes it regulable with a simple potentiometer? If Robin's motor just happens to be of the same type (we do not know this) just buying a potentiometer will suffice. (Last time I dabbled with this stuff it would have been a rheostat... no semiconductors yet!)

Usually in AC motors the speed is controlled by the hertz, not the volts, hence the electronics is a very different to DC which can easily be controlled by a pot. Ive been looking as well but there are no cheap solutions. For the $A500 it would cost you can almost get a new lathe.

The motor has indicated is a 3 phase motor with some fancy electronics built in. There is no other boxes or connections needed.

You use a standard single phase power point to plug into.
The motor is 1hp constant torque with a speed range of 550rpm -1700 rpm.

Now coupled with your existing pulley setup you can have quite a few speed options from very slow to very very fast.
You have to work out the driver against the driven to get the range on each pulley setup.

All this with constant torque which is what a woodturner requires. So you can turn a very out of round bowl at a slow speed and still have good torque and not stall the motor all the time.

Please note it will not fit onto the MC900-1100 asian variety of lathes as the mounting of the motor is not suitable, plus the motor is physically bigger so reducing the diameter of work you can do.
The main thing to get used to is that you turn the power on at the main switch and about a minute later all the electronics have warmed up and you are ready to go, you must only turn the lathe on and of at the pendant, if you turn on and of at the power point you confuse the electronics and it will just stop and not go anywhere. It is an easy thing to get used to.
The lead from the motor is 1.5m long so the switch can be placed in an easy to get to position.

If you have seen Neil {"U Beaut"} demo the rotary sander at the shows you will have seen the motor running as this is the motor he has on his lathe.

A lot of people with older lathes are upgrading to this motor as they have a shop full of accessories for their current lathe and do not want to go to the bother of changing chucks, faceplates and othe accessories they have, this is a cheaper option.

Thanks, got the idea (I think). I gather that the "fancy electronics built in" is a rectifier and the motor runs on DC. While we are on the topic (sorry if it is a bit hijacking) I have seen 1.5 HP motors advertised as "allowing bigger work". I can't really see any substantial advantage over 1HP in practical terms, assuming constant torque, and the potential disadvantage of higher power in a bad dig in situation. Am I missing something important? In what situations the added power would really matter?

Thanks, got the idea (I think). I gather that the "fancy electronics built in" is a rectifier and the motor runs on DC.

Not really converts single phase to DC then to 3phase for the 3 phase motor. The DC set-up is usaully on the smaller variety.

I have seen 1.5 HP motors advertised as "allowing bigger work". I can't really see any substantial advantage over 1HP in practical terms, assuming constant torque, and the potential disadvantage of higher power in a bad dig in situation. Am I missing something important? In what situations the added power would really matter?

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I have stalled my 1hp several times at full speed. So personally I would prefer 1.5-2hp. My most recent lathe has 1.5kw motor which is just over 2hp. yeehaa

Hughie just gotta ask.

What were you turning that you stalled a lathe at full speed.