X axis drive

[mechman48]

Finally got all the bits together to fit a power drive to my mill x axis; a 12v window wiper motor, 110/220v -12v transformer, 12v PWM speed controller, some 3 core cable & some other bits 'n' bobs. I made up the framework from some 10mm aluminium plate, a couple of 10mm rounds. For the coupling I used a couple of spare sockets I had from an old imperial set together with a universal joint from the same set, to link the two I fitted a piece of 1/4" key steel with a spring over to keep the two sockets located on the modified leadscrew end & the motor shaft. I fabricated a cover from a piece of .5mm aluminium sheet I bought from a local DIY retailer & fastened on to the framework with a couple of 4mm SHCS.

It works quite well, giving me linear speeds of.. @ min.rpm - 18mm/ per min. & at the fastest rpm - 140 mm/per min....  max motor- speed 30rpm. The only thing that is concerning me is a after a few minutes operation (trial run) the motor seems to get overly warm so I was querying have I missed something in the build? I have tested the amperage... low rev amps- 2... max rev amps- 3.8, PWM speed controller input 12.2v output... 12.1v. Have put a torque wrench on to the leadscrew & it doesn't even register 1ft/lb to turn  so there isn't a lot of resistance. Can anyone assist? 

Have att. some pics for your perusal...

[Bluechip]

George:

[1] 12v transformer ? I do hope there is a rectifier in there somewhere ??

[2] A 12V transformer will be giving some 17V if rectified and a smoothing cap. attached.

[3] Wiper motors do tend to run a bit warm but not really hot. If it warms up then stabilises at that temp. it's probably OK. These motors are continuously rated to all intents and purposes ... they are expected to run for hours on end ..

Any clue as to what temp. it gets to?

Dave

[mechman48]

Dave,
Thanks for your response... Transformer bought on e bay (China) with description including overload protection, in line fuse, switchable voltage, blah, blah, & it aint a little thing so I am making the assumption that it will include a rectifier ? If  I can find the details I will post for your delectation. Another transformer I considered was just a block of windings in a frame... 240v in & 12v out (3 wires in ? - 2 out) with no pc board containing resistors, capacitors, heat sinks etc. etc hence why I'm assuming the one in use will have a rectifier  .

Cheers
George

[mechman48]

Dave ... Transformer link...as best as I can remember..

http://www.ebay.co.uk/itm/Hot-AC-110V-220V-to-DC-12V-10A-120W-Voltage-Transformer-Switch-Power-Supply-/221503522940?pt=UK_Light_Fittings&hash=item3392a3887c

[Bigbadbugga]

 I was hoping to build one using a stepper motor and an arduino, but this looks like a neat solution too.

Any video of it in action?

[Bluechip]

That looks fine, George 

Just a general purpose switch mode supply. I was a bit concerned you described it as a 'transformer' which is just AC in and AC out ... As you were, carry on ... just ignore me ... 

Dave

[mechman48]

Test running X axis drive...

[Bigbadbugga]

I like that, runs real smooth.

[BaronJ]

Hi George,

I've built a couple of mill table drives using wiper motors !  If you have it wired correctly they are very hard to stall.
At the moment I am using a 30 volt @ 3 amp variable power supply.  Neither motor takes more than a couple of amps at 12 volts.  My two motors are slightly different.  One uses the motor case as one of the connections and I suspect that is what you have.  If you feed power to the two wires the motor will rapidly get hot and won't produce a lot of torque.  One wire will give you low speed and the other will give you high speed.

I do have photographs but they are on another computer that I don't have access to at the moment.  Or you can check out this link.

 http://www.woodworkforums.com/184913-table-traverse-chinese-mill/

You will have to register to view the pictures.  But you will also be able to read the whole thread about both table traverse builds.