[Agenthoover]

New here so hello from me and i will get staraight to it... I have a small Unimat SL lathe that i am teaching my eldest son to use for his RC car fetish.. as most will know the motor sucks big time.... looking around on the forum another member used a 24 volt scooter motor... but there was no mention of power supply... which i might add is not as easy to come by as i first thought.

Could some one tell me if the following items are ok to use together..

Power Supply ..CNC Servo Step Motor Driver AC-DC Power Supply 24V 15A CNC Servo Step Motor Driver AC-DC Power Supply 24V 15A | eBay

Scooter Motor .. 24 VOLT 250 WATT ELECTRIC E-SCOOTER MOTOR 24v 250w | eBay

Speed Controller... 12V 15A PWM DC Motor Speed Control Regulate RC Model | eBay

Im a little lost with regards to getting power for the motor.. been stuck on this for the past week so any help would be appreciated.... cheers.

Edit... Just found this one too .. http://www.ebay.co.uk/itm/2710098888...84.m1423.l2649

[Agenthoover]

Has anyone got any ideas on this.. its got me a little stuck tbh.... cheers.

[Al_The_Man]

I make 24v @ 14amps 336w?
Do you intend using it as a servo motor?
These motors probably do not have the refined features of a servo and also you would need a encoder, or is the intention for a spindle motor? which should work..
Al.

[boldford]

Cheap 24V or 36V PSUs can be easily constructed by connecting two or three PC PSUs in series following the appropriate precautions.

[Agenthoover]

I make 24v @ 14amps 336w?
Do you intend using it as a servo motor?
These motors probably do not have the refined features of a servo and also you would need a encoder, or is the intention for a spindle motor? which should work..
Al.

All i am wanting is to run the lathe as a regular lathe, i was going to use the motor listed above, using that motor seems to be the done thing amongst guys in Yahoo user groups.... all i want is a decent 24v power supply to power it... cheers..

[Al_The_Man]

How do you intend to control motor rpm?
You don't need anything very sophisticated such as switching or regulated supplies, you can also get away without the reservoir capacitor, just a full wave bridge will work, if you can find a suitable output transformer , if using a bridge only, you can use a 24vac secondary type.
Another way, if you take care how you wire the output as to the neutral is to use a variac with a bridge on the output for supply and control of speed and , if going this route you need to place a stop on the control knob to avoid over voltage.
Al.

[Agenthoover]

How do you intend to control motor rpm?
You don't need anything very sophisticated such as switching or regulated supplies, you can also get away without the reservoir capacitor, just a full wave bridge will work, if you can find a suitable output transformer , if using a bridge only, you can use a 24vac secondary type.
Another way, if you take care how you wire the output as to the neutral is to use a variac with a bridge on the output for supply and control of speed and , if going this route you need to place a stop on the control knob to avoid over voltage.
Al.

Lol... you have just taken me into a world full of confusion haha, this stuff is all beyond me tbh so was just looking for off the shelf stuff, with regards to speed control i was just going to use a simple 12 to 24 volt PWM speed controller, however, finding the right one here in the UK is proving difficult, they all seem to be 10A max... that motor runs at 14A... still looking tho.

[Agenthoover]

Something like this but the amp rating is too low 12V-40V 10A Pulse Width Modulation PWM DC Motor Speed Control Switch Governor UK | eBay

[Al_The_Man]

The motor is Capable of 14A, most of the time it would be running well below, probably.
And just make sure when the power is applied that the speed is set to zero to avoid a high initial current.
The unit in the link has a 10amp fuse which should limit the issue, if you did go over.
Al.

[Agenthoover]

The motor is Capable of 14A, most of the time it would be running well below, probably.
And just make sure when the power is applied that the speed is set to zero to avoid a high initial current.
The unit in the link has a 10amp fuse which should limit the issue, if you did go over.
Al.

Ok Al... thanks for the help... on a side note, what you think about adding a simple volume/tone style pot to one of these.. they are made for scooters so i cant see why not.. but im me...lol ... it saves me hunting around for a decent enclosure too.

24V 250W Speed Controller for Electric Scooters | eBay

24V 350W Speed Controller Box Electric Bike Scooter | eBay

[Al_The_Man]

I would think the 350w would do it to be on the safe side, I assume the 'Throttle' is the 3 wires to the Pot?
Al.

[Agenthoover]

I would think the 350w would do it to be on the safe side, I assume the 'Throttle' is the 3 wires to the Pot?
Al.

Yes thats what i thought too.. you know what my next question is going to be dont you...lol... which wire goes where on the pot... plus would i use a 250k.. 500k and so on.

[Al_The_Man]

I would expect the wiring diagram would explain all?
The normal value is 5k to 10k.
Make sure you buy linear version, not logarithmic!.
Al.

[Agenthoover]

Well watch this space ...lol.. i've had instructions for stuff in the past and it makes me wonder why they bothered.. it will be interesting if they aint up to much.... i will post a pic of me with my hair standing on end if all does not go to plan ..lol

[underthetire]

I kinda wonder why not just get a brushed 110vac motor and a router speed control from harbor freight. Seems easy and cheap, no power supply required.

[Agenthoover]

I kinda wonder why not just get a brushed 110vac motor and a router speed control from harbor freight. Seems easy and cheap, no power supply required.

I had considered that.. also a scroll saw motor, but they are to damn loud...lol.. specially the router motors..plus this little lathe has turned into a hobby in itself and me being a compulsive fiddler i just gotta do these things...lol... also the power supply will alow me to run power feed motors too.

[wizard]

I could be wrong about that but this is a simple machine tool that should be easy to plug into a wall outlets. Further I can't realistically see this lathe using a lot of power reliably so the first step would be to determine a realistic maximum HP rating for the motor.

At that point you have three reasonable choices.

1. Consider buying a cheap single phase fractional HP motor that will do the job and make use of the existing belt drive solution. It may even be possible to find a realtively small multispeed motor. Single phase fractional horse power motors are manufactured by the millions, in so many variants as to make ones head spin.
2. Install a cheap DC motor with a suitable DC speed controller. This would be a brushed motor, but on a hobby type device would likely last for as long as the owner would. Combined with the existing belt drive you will get stable operation over a wide array of speeds without much fuss.
3. Consider a 3Phase induction motor with a variable speed drive. Don't let the 3 Phase scare you off, for a fractional HP motor, available drives can handle the motor without issue from single phase power sources. Such arraingements have become very cost competitive these days and can often be more cost effective than DC motors.

Note that each solution above is designed to operate from line voltages, It makes little sense to add complexity to your drive solution when you can get everything needed in one box. In the first case you need an on/off switch with each of the following case getting more complicated. Complicated is relative here, solutions 2 & 3 are far less of an issue than a DIY approach to lathe control.

In fact if you look around a bit you should be able to find DC motors with the controller built right into the motors end cap. You may even be able to find AC motors with built in controllers. You don't have to go that way of course as there are benefits to having the controller separated from the motor, I just want to point out that there are many options available.

In the end I don't see a valid reason to go with a half a$$ approach when the market is flooded with many solutions for such a lathe upgrade. Here we are talking about solutions that run with a minimal of effort from your home power system.

The other issue here is overkill on this platform. Is the lather really worth the effort of putting a servo system on it? Id say no. In fact if you want a small CNC capable lathe I'd have to say you would be better off building your own from the ground up.