Coverting a Manual Lathe to VSD

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1coolbanana
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Coverting a Manual Lathe to VSD

Postby 1coolbanana » Mon Feb 27, 2017 12:48 pm

Thought this maybe helpful to someone......maybe not :?

Converting my little manual speed changing (via belts and pulleys) to a DC variable speed drive.

I suppose I should start at the beginning.......
My lathe uses a custom size AC 240 volt single phase motor which from what I read is prone to failure.
You cant buy these as a spare part and no other off the shelf AC motor of the same or greater power fits into the allowable space.
Changing the belts constantly for the 6 speeds is a pain.

Enter DC variable speed drives and controllers.
The DC motors for some reason are much more compact and are higher HP for equivalent size.
The original motor is 1/2 hp, the same sized DC motor Ive got is 1.75hp.

They seem easy to find and relatively cheap, used treadmill motors are the best and cheapest source and what is commonly used for this type of mod.
Control is commonly by modified treadmill control boards or proprietary boards which there are many of but are a bit expensive especially here in Oz.

I never really considered 3 phase VFD as they are expensive and Im not wanting to go to 3 phase as I dont have 3 phase at that end of the shed, dont want to rewire the shed or move the lathe.
I dont think VFD works on single phase but then Ive still got the same problem of size and unreliable original motor.

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I got the DC 1.75hp treadmill motor (free), got the meters from China and the proxy switches for $20 each, a box to put them in for $7, old wall wart (free)......

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Tested the tacho and Hall sensors running the motor off an 18 volt battery
This is just for the RPM display.

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Soldered everything up and boxed it all up with an old 9 volt wall wart power supply (just for the tachs, 5-30 volt)

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And it works Thumbsup

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One is for motor RPM and the other is work spindle RPM

Waiting for the DC controller parts to arrive and then theres a bit of machining and tuning to do
Cowabunga dudes .......

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1coolbanana
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Location: NW Sydney

Re: Coverting a Manual Lathe to VSD

Postby 1coolbanana » Mon Feb 27, 2017 12:49 pm

Got the used controller from the US the other day which promptly exploded in a ball of black soot so it was back to the drawing board and I ordered a new controller.

So while I was waiting and in the evenings over xmas I did a bit more work

Since I added the tacho pickup to the cooling fan, I had to balance as it can do up to 5000 rpm

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The point of no return

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Old motor removal.
Just in case I have to go back and refit the original induction motor I thought Id better make a note of the wiring

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Drilling and tapping the end of the shaft of the new motor was easy but lengthening the keyway was a bugger of a job

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Drilling and tapping out the new mounting points for the DC motor and setting up the pulley alignments

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Setting up the hall sensors for the tachos and a trial run using a cordless drill battery

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Headstock back together and just have to finish the wiring for the controller and E stop and getting close to being done

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Its only a toy lathe compared to what Im used to but does most things I need, anyway, keeps me out of the fridge :smile:
Cowabunga dudes .......

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1coolbanana
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Location: NW Sydney

Re: Coverting a Manual Lathe to VSD

Postby 1coolbanana » Mon Feb 27, 2017 12:50 pm

I wasnt expecting this to turn up yet but finally the last piece of the puzzle

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Fitted up the brake switching the wiring and the E stop

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Fitted up to the machine

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First test :happy1:

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Did a bit more testing and all seems good maybe a little tuning on the Load compensation but pretty good at default settings :smile:

First cut.......sweet as

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Absolutely worth it and fun to do. :thumb:
Very time saving to being able to dial in the speed without messing about with belts and pulleys.
It was difficult not to be lazy with the old system and just use whatever speed it was set up for but now, with the turn of the dial, you get optimum speeds and feeds.
Just means, easier to use, faster and better results and finishes.
I like it

Got to think up a job now dunno

And another project :D
Cowabunga dudes .......

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Wodger63
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Re: Coverting a Manual Lathe to VSD

Postby Wodger63 » Tue Feb 28, 2017 4:15 pm

Waiting for the next project. :popcorn:

darren
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Re: Coverting a Manual Lathe to VSD

Postby darren » Wed Mar 01, 2017 4:43 am

How does it go with pulsing at low speeds? Years ago i was involved with making a portable line borer with a VSD and it did that a bit but things would have improved a lot i suppose
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1coolbanana
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Re: Coverting a Manual Lathe to VSD

Postby 1coolbanana » Wed Mar 01, 2017 7:47 am

Works really well, no pulsing and the control is load/torque sensing and maintains speed with the varying cut load well.
Its only a toy after all but big enough that I was able to machine a triple clamp steering stem so does most things I need except screwcutting which is the only major drawback.
I could possibly do a CNC conversion but I dont think its worth it on this thing.

This was for a KTM640 conversion on a 750 Tenere

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Cowabunga dudes .......

darren
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Re: Coverting a Manual Lathe to VSD

Postby darren » Wed Mar 01, 2017 7:10 pm

Good stuff.
I have know a few who owned the AL-960 in its various guises but i have my sights set on this

https://www.machineryhouse.com.au/L242D i only have single phase but i already have one of these at home but have never used it

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maybe this year..
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1coolbanana
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Re: Coverting a Manual Lathe to VSD

Postby 1coolbanana » Wed Mar 01, 2017 7:32 pm

Thats what I have a work. Not great. But reasonable for the price.
For that money Id look for a nice used Colchester Triumph or similar.
http://bluediamondmachinetools.co.uk/pr ... furbished/
Ive had one and really, they are great, tough, high accuracy and bulletproof
Would be a better long term proposition.


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Cowabunga dudes .......

darren
Posts: 474
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Location: Hunter Valley

Re: Coverting a Manual Lathe to VSD

Postby darren » Wed Mar 01, 2017 8:09 pm

Its on the other side of the world though.

I did my time on Russian production lathes, tough as, power quick tramming in all directions, automatic band brakes so you just slammed it into reverse at whatever speed, I later ran a machine shop and all their smaller lathes were colchesters, nice things though a little slower.
For 9 k i can get one of those new or something with the arse flogged out of it.
Ill see how things turn out
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1coolbanana
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Re: Coverting a Manual Lathe to VSD

Postby 1coolbanana » Wed Mar 01, 2017 8:18 pm

I did my time in toolrooms that still used line shafts :lol:
Broens in Ingleburn, one of the biggest toolrooms that was left has gone bust.
Actually bought out by the Chinese and shut down :(
All the 3 phase smaller stuff is going cheap from what I hear.
They have everything you can imagine that a toolroom would have for sale.
Might be worth a google.
Cowabunga dudes .......


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