Variable speed

[al.m..]

Rory,
i have been doing a lot of reading today( home sick). One thing I came across was a thread from here a couple years ago where you said you were going to build a controller out of a 400w scr,a bridge rectifier,and a 5ohm potentiometer.
How did that work out?

I played around with that for a month or so, but could never get something that I was satisfied with. In the end, at that time I concluded that the DC 51controllers were far superior to anything that I could build. Since that time I have discovered that not all DC 51 controllers are created equal. My go to controller is an MC 60 from an old treadmill.[/QUOTE]
there are numerous free treadmills near me,wish I could narrow down what might have the mc-60 board.
what spec pot have you found works best?

[tool fan]

You are absolutely correct about cooling. On the DC motors there is usually one and sometimes 2 fans that help keep the motor cool. However they spin at the same rate as the motor so at low speeds I am not sure that they are effective.

Nice setup on the drill press by the way

Rory,
i have been doing a lot of reading today( home sick). One thing I came across was a thread from here a couple years ago where you said you were going to build a controller out of a 400w scr,a bridge rectifier,and a 5ohm potentiometer.
How did that work out?
[/QUOTE]

I played around with that for a month or so, but could never get something that I was satisfied with. In the end, at that time I concluded that the DC 51controllers were far superior to anything that I could build. Since that time I have discovered that not all DC 51 controllers are created equal. My go to controller is an MC 60 from an old treadmill.

[al.m..]

You are absolutely correct about cooling. On the DC motors there is usually one and sometimes 2 fans that help keep the motor cool. However they spin at the same rate as the motor so at low speeds I am not sure that they are effective.

Nice setup on the drill press by the way[/QUOTE]
Rory,
i have been doing a lot of reading today( home sick). One thing I came across was a thread from here a couple years ago where you said you were going to build a controller out of a 400w scr,a bridge rectifier,and a 5ohm potentiometer.
How did that work out?

[tool fan]

Lathe or drill press, they are about the same machine in my eyes.

In my opinion, you reduce the RPM of a motor and put large loads on whether DC or AC you need to watch the cooling.

My Lathe has a 3hp 1750 RPM motor on VFD with three belts.

My drill press has a 2 hp motor 865 RPM. It is geared 1 to 1 motor ratio to spindle. I overrun the motor to get up to 1200 rpm at the spindle. At 2 RPM you cannot stop that spindle, as I set the VFD in sensor less vector control... but the motor can get extremely hot in about 10 minutes.

You are absolutely correct about cooling. On the DC motors there is usually one and sometimes 2 fans that help keep the motor cool. However they spin at the same rate as the motor so at low speeds I am not sure that they are effective.

Nice setup on the drill press by the way

[billh]

I agree, the operating characteristics between lathe and drill press are as Cole Porter said, "Night and Day". Younger members may Google Cole Porter.
billh

[iamtooler]

Lathe or drill press, they are about the same machine in my eyes.

In my opinion, you reduce the RPM of a motor and put large loads on whether DC or AC you need to watch the cooling.

Not even close to the same in my view. A lathe in the hands of an expert slicing off rivers of wood for hours at a time is a near constant high demand application. It is difficult to load a drill bit for more than a few seconds at a time and at very low rpm the torque is limited by the drive train so the power (speed times torque) is also limited.

[Matt Matt]

Lathe or drill press, they are about the same machine in my eyes.

In my opinion, you reduce the RPM of a motor and put large loads on whether DC or AC you need to watch the cooling.

My Lathe has a 3hp 1750 RPM motor on VFD with three belts.

My drill press has a 2 hp motor 865 RPM. It is geared 1 to 1 motor ratio to spindle. I overrun the motor to get up to 1200 rpm at the spindle. At 2 RPM you cannot stop that spindle, as I set the VFD in sensor less vector control... but the motor can get extremely hot in about 10 minutes.

[tool fan]

I have not heard of a motor failing. Post a picture of your motor with a ruler for reference and I’ll tell you what I think


Sent from my iPhone using Tapatalk

[al.m..]

I have been putting treadmill motors and 3 phase motors with VFD's on lathes for the past few years. What I have learned is that the HP rating on the treadmill motors is some theoretical maximum and is in no way what you might expect. Mass seems to be more important i.e. bigger motors are better.

The control circuit board is also important. If you can find an MC 60 control board, it will work on any treadmill motor that I have found and deliver enough amperage to achieve sufficient torque at low speed. The MC 60 boards are on the older treadmills that have dials or slides to change the speed. Unfortunately these treadmills have the little "2.5 or 2.75 HP motors that are inadequate.

Also important, is to keep the heavy flywheel on the motors. This usually requires some modification to the belt drive section of the flywheel. I generally turn that part down to 5/8" or 3/4" and attach a stepped pulley to that stub. The flywheels are sometimes screwed onto the drive shaft with a left hand thread. This needs to be secured with a set screw.

The nice thing is that treadmills can be found for free. The not so nice thing is that sometimes 2 treadmills are required (one for the motor and one for the control board).

Attached are a couple of motors that are perfectly adequate for a Beaver, Rockwell, Delta, Walker Turner lathes when combined with an MC 60 board.

The second picture is just the label on the motor but it was the "best" one that I have encountered. Even at 100 rpm, I could not stop the spindle from spinning with that motor.

VFD's and 3 phase motors are great (but not free). With VFD's it is possible to increase low rpm torque.

I hope that this helps.

thank you for your input
you did not comment on durability,do these treadmill motors pass the test of time?
the one I have,at 2.75 peak,1.5 continuos,is it enough for my lathe,or at least a drill press?

[tool fan]

Check out this from Tool Fan [Rory] on using treadmill parts on a lathe. He could probably give you a good idea how long the components would last with use on your lathe.
https://forum.canadianwoodworking.co...-46-wood-lathe

I have been putting treadmill motors and 3 phase motors with VFD's on lathes for the past few years. What I have learned is that the HP rating on the treadmill motors is some theoretical maximum and is in no way what you might expect. Mass seems to be more important i.e. bigger motors are better.

The control circuit board is also important. If you can find an MC 60 control board, it will work on any treadmill motor that I have found and deliver enough amperage to achieve sufficient torque at low speed. The MC 60 boards are on the older treadmills that have dials or slides to change the speed. Unfortunately these treadmills have the little "2.5 or 2.75 HP motors that are inadequate.

Also important, is to keep the heavy flywheel on the motors. This usually requires some modification to the belt drive section of the flywheel. I generally turn that part down to 5/8" or 3/4" and attach a stepped pulley to that stub. The flywheels are sometimes screwed onto the drive shaft with a left hand thread. This needs to be secured with a set screw.

The nice thing is that treadmills can be found for free. The not so nice thing is that sometimes 2 treadmills are required (one for the motor and one for the control board).

Attached are a couple of motors that are perfectly adequate for a Beaver, Rockwell, Delta, Walker Turner lathes when combined with an MC 60 board.

The second picture is just the label on the motor but it was the "best" one that I have encountered. Even at 100 rpm, I could not stop the spindle from spinning with that motor.

VFD's and 3 phase motors are great (but not free). With VFD's it is possible to increase low rpm torque.

I hope that this helps.

[al.m..]

Tore down the treadmill,motor is 2.75 peak hp,1.5 hp continuos duty

[Frank English]

Check out this from Tool Fan [Rory] on using treadmill parts on a lathe. He could probably give you a good idea how long the components would last with use on your lathe.
https://forum.canadianwoodworking.co...-46-wood-lathe

[al.m..]

If have quickly discovered free treadmills in perfect working order are ten cents less than a dime a dozen,not much to lose

[billh]

The 3-phase motor and VFD is the better way to get variable speed but people have used treadmill motors. Scavenging a motor and controller from a junked treadmill is likely to be very inexpensive and this made them attractive when VFDs were much more expensive than they are now.

You have to be a bit leery of HP ratings if they are things like Peak or Treadmill rather than Continuous. Also, some motors run at high RPM which means reduction pulleys are essential but a pulley system may be a good idea for any motor to keep it in a good torque range. You need the controller board that powers the motor.

billh

[iamtooler]

It would have to be a very expensive treadmill that would yield a motor powerful enough to survive long service on a lathe especially if you want to turn bowls. If you don't mind scrounging used parts I suggest you go with a 2-3 hp 3 phase motor and a used vfd rather than old treadmills. You should still set up a jackshaft with large pulleys that will enable the motor to run fast enough to produce power and transmit it to the spindle.