I need some expertise please

[gharlan]

I have come across a lathe that I wish to get up and running. It was not originally a wood lathe but I think it would adapt easily. It has a DC motor on it but no controls or power supply. I am afraid I have never messed with DC motors so I know nothing about them. So what do I need and where do I look to get it going. The motor is a 90 volt DC and runs 1800 rpm with .75 hp. Here are a couple of pics of the lathe.

The motor side

I am excited about this find as it will swing 35" on the inboard side with 4'6" between centers. If I flip the spindle around I could swing about 7'6". So I need to be able to go S-L-O-W as well as speed it up for smaller pieces. I looked into just installing a big ac motor  and a series of jack shafts but it seems difficult to be able to get speeds near 10 rpm and still be able to have much speed when called for. I really have no clue if This .75 horse DC  will pull what I need. As I said I know nothing about them. So any help you may give I would appreciate. Thanks Gary

[Fla._Deadheader]

We bought a PWM off ebay, and use it to power feed the sawhead. It pulses voltage to the motor, and the motor is ¾ HP.

  Cost around $75.00, or so. You start at 0 RPM's and turn up the speed as you want-need.  Might work well for that.

[beenthere]

The lathe looks interesting, but from the pics, it looks a bit light weight for serious turning. But looks are deceiving sometimes.  The casters are one clue to how light it is too.

Taking that into consideration, and how the rpm relates to rim speed of large diameter turnings, you may have a great time turning wood with this.

Any idea what it was built to do?  Looks like it had a very specific use, and the faceplate was a later addition.

[gharlan]

Fla._Deadheader  What is a PWM? And is that for a DC motor or AC? If I go AC I am going to go with a 5 hp 850 rpm that I have. I am a little skeptical of the .75 having enough stuff to pull a cut on a big diameter.

beenthere  The lathe is actually quite heavy and is a little over 5 feet wide at the base. The casters work well and also have built in jacks to lift it off the casters for more stability. I know I may have to bolt it to the floor though as I have seen my  model 90 lathe do a dance to many times.  From talking to the guy I got it from (he got it from a scrap yard) I think it was used in rewinding electric motors. It had a shaft that ran on one side that was also driven. It had some sort of gear head that was adjustable for length of travel before returning. Anyway the other parts were missing when I got it, but I did see the gear head. Anyway it appeared that something was going up and back along the product that was turning in the lathe. The rewinding may be totally off but it seemed to fit in with what little I know in the world.  I think the face plate has always been there by the way it all fits together. The plate is 1" aluminum and made to bolt a chuck to although the chuck was not there.  Now if I can just get it to turning. I would love to cut some 4' cookies and see what can come from it. I think if nothing else I can always use it to build some round tables if I make a jig to hold a router to it while turning slowly

[beenthere]

Thanks gary
That paints a good mental pic of what you have, along with the pics. Should be fun to work it into your turning plans.

[Fla._Deadheader]

 PWM

  http://cgi.ebay.com/80-Amp-PWM-DC-MOTOR-SPEED-CONTROL-robotics_W0QQitemZ330219720079QQihZ014QQcategoryZ71393QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

  I'm too dumb to shorten the link.

  This only goes to 36 Volts. There are MANY that are made for 90V DC operation.

[pineywoods]

PWM = Pulse Width Modulation. works on DC motors only. Picture a fast little monkey that can flip the on/off switch 2000 times a second. The ratio of on time to off time controls the speed. The forward speed controller on woodmizers is PWM. There is a type avilable for ac power, but the output to the motor is still dc,most commonly 90 volts.  AC motors require VFC=variable frequency control.. output is ac but the frequency  varies ie not necessarily 50-60 cycle.

[gharlan]

I have been searching for a 90 volt pwm. I have come across many in my search but the highest voltage so far is 58 volts. Anybody know where i might find a larger one? Thanks     Gary

[raycon]

A starting point to consider is McMaster Carr (google mcmaster carr and search DC motor control)
Below is a cut and paste from one of the online catalog pages. If you call and inquire about a specific item they'll tell you who the manufacture is.Curious as to what your target RPM range is?

(From page 857  online catalog)
AC to DC Motor Speed Controllers
   Input a single-phase (50/60 Hz) AC voltage and get a variable DC voltage output to control the speed of your 90 VDC or 180 VDC permanent-magnet motor. Choose from open-frame, indoor use (NEMA 1), and water tight for outdoor use (NEMA 4X) enclosures (NEMA enclosure ratings differ from NEMA frame sizes). Controllers have an on/off switch, knob for DC output adjustment (open-frame controller has a variable switch), and screw-terminal connections. UL and C-UL listed; CSA certified (unless noted). Reversing controllers allow you to reverse the motor's shaft rotation.
   Heat sinks are sold separately. They are required for open-frame and indoor use (NEMA 1) controllers when an output greater than 5 amps is needed.

[gharlan]

Thank You raycon. i will google them shortly and see what I can find. With the sheaves already on the lathe my speed would be from 0 to 265 rpm. I thought I would start there and see what I may need as I use it. I hope the 265 will be plenty on the top end. I will still have the powermatic if I need to go faster but my swing is limited there so we will see.  thanks again   gary