Announcement

Collapse
No announcement yet.

Variable speed

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • guylavoie
    replied
    I dismantled a Bremshay treadmill that I got for free and studied the motor controller. The controller itself would send power to the motor in discrete steps, incremented or decremented by pulses coming from the main treadmill board. A tachometer (hall effect sensor and magnet) would feed back once per rotation pulses to the main board, and the main board would send up/down pulses to the motor controller in response to varying load conditions, to maintain the set speed. Making a variable speed lathe with this controller would thus involve a control that could send speed up/down pulses. I thought of doing it, with a microcontroller, but ended up going simpler using just a DC motor controller that uses a pot to set the speed.

    Leave a comment:


  • al.m..
    replied
    Harvested a functioning mc-60 circuit board and 10 ohm pot out of the second tree treadmill.althogh the motors out of the first and second have the same hp rating the one out of the first has a higher amperage rating and a more usable type foot.just need to adapt a pulley and tidy up the assembly and I have a vintage variable speed lathe

    Leave a comment:


  • tool fan
    replied

    Leave a comment:


  • al.m..
    replied
    Originally posted by tool fan View Post
    If there are pictures of the controls, look for one that has a dial or a slide to control the speed. Old Weslo's are generally this kind. 10 ohm pots are what I find work well.
    awsome
    i am suposta pick up a Weslo,with sliding speed control latter in the week.display does not work,but speed control does,free.
    hopfully no one else get there before me

    Leave a comment:


  • tool fan
    replied
    If there are pictures of the controls, look for one that has a dial or a slide to control the speed. Old Weslo's are generally this kind. 10 ohm pots are what I find work well.

    Leave a comment:


  • al.m..
    replied
    Originally posted by tool fan View Post
    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?

    Leave a comment:


  • tool fan
    replied
    Originally posted by al.m.. View Post

    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.

    Leave a comment:


  • al.m..
    replied


    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?
    Last edited by al.m..; 01-13-2020, 11:55 AM.

    Leave a comment:


  • tool fan
    replied
    Originally posted by Matt Matt View Post
    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.

    Click image for larger version

Name:	A9C57B3F-8698-4CEC-A062-B7624532004C.jpeg
Views:	573
Size:	711.9 KB
ID:	1265887
    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

    Leave a comment:


  • billh
    replied
    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

    Leave a comment:


  • iamtooler
    replied
    Originally posted by Matt Matt View Post
    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.

    Leave a comment:


  • Matt Matt
    replied
    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.

    Click image for larger version

Name:	A9C57B3F-8698-4CEC-A062-B7624532004C.jpeg
Views:	573
Size:	711.9 KB
ID:	1265887

    Leave a comment:


  • tool fan
    replied
    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

    Leave a comment:


  • al.m..
    replied
    Originally posted by tool fan View Post

    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?

    Leave a comment:


  • tool fan
    replied
    Originally posted by Frank English View Post
    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.

    Leave a comment:

Working...
X