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  • tool fan
    replied
    Originally posted by al.m.. View Post
    fan is cast into the flywheel,otherwise I would ditch it

    Leave a comment:


  • guylavoie
    replied
    Originally posted by iamtooler View Post

    This control does not react to slowing of motor, does it send continuous voltage rather than pulsed? How do you know if the motor is overloaded?
    Rob
    I haven't looked at the voltage applied to the motor with an oscilloscope to see if it's pulsed. I'm quite sure it must be doing something like that because the torque is still pretty good at low speeds, and the heat sinks on the board would need to be much bigger for something that would produce a high current, variable voltage.

    There is an overload indication (LED) on the board itself. Otherwise, you'd probably have to judge by how much it slows down if you're demanding too much.

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  • al.m..
    replied
    Originally posted by iamtooler View Post
    I am a big fan of flywheels but I am not sure it is of any use in this application, just a larger start torque requirement as there is a fair mount of rotating mass with a wood lathe.
    Rob
    fan is cast into the flywheel,otherwise I would ditch it

    Leave a comment:


  • tool fan
    replied

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  • iamtooler
    replied
    Originally posted by guylavoie View Post
    Well if it's like the controller board I had on the treadmill (DCMD57) it would be possible to use it with nothing more than two pushbuttons (each one between an input and common) to increase or decrease the speed, but if you have to press it 25 or 30 times each time you turn the lathe back on to get it up to speed, that would get old real quick. A straight DC motor control is much easier.

    I got this one:

    https://www.ebay.com/itm/AC-110V-220...IAAOSwlTBdkUGj
    This control does not react to slowing of motor, does it send continuous voltage rather than pulsed? How do you know if the motor is overloaded?
    Rob

    Leave a comment:


  • iamtooler
    replied
    I am a big fan of flywheels but I am not sure it is of any use in this application, just a larger start torque requirement as there is a fair mount of rotating mass with a wood lathe.
    Rob

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  • tool fan
    replied

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  • al.m..
    replied
    Originally posted by tool fan View Post
    I was wondering what controller you were referring to. I tried one of those and while it worked better than the smaller dc 51 controllers the MC 60 from an old treadmill was superior in terms of delivering low speed torque


    Sent from my iPhone using Tapatalk
    im going to start with the mc-60 and swe how it works out.
    while I have your attention,I have a couple ideas about pulleys,going to take some machining ( my brother has a small metal lathe.)
    what have you done?did you keep the the flywheel? I'm thinking it is needed for cooling

    Leave a comment:


  • tool fan
    replied
    I was wondering what controller you were referring to. I tried one of those and while it worked better than the smaller dc 51 controllers the MC 60 from an old treadmill was superior in terms of delivering low speed torque


    Sent from my iPhone using Tapatalk

    Leave a comment:


  • guylavoie
    replied
    Well if it's like the controller board I had on the treadmill (DCMD57) it would be possible to use it with nothing more than two pushbuttons (each one between an input and common) to increase or decrease the speed, but if you have to press it 25 or 30 times each time you turn the lathe back on to get it up to speed, that would get old real quick. A straight DC motor control is much easier.

    I got this one:

    https://www.ebay.com/itm/AC-110V-220...IAAOSwlTBdkUGj

    Leave a comment:


  • tool fan
    replied
    Originally posted by guylavoie View Post
    In my case, disconnecting the tachometer input would cause the main board to stop the motor and display an error message. This is a failsafe safety issue, not wanting to speed up the treadmill and hurt the treadmill user if for some reason the tachometer was defective.
    I have struggled to find a way to use those boards without using the entire control panel, i.e. use the board and a pot to run the motor. Even with the treadmill hall effect sensor and magnet it seems that the motor responds to other sensors and stops. I eventually gave up in favour of the mc 60 boards.

    Leave a comment:


  • guylavoie
    replied
    In my case, disconnecting the tachometer input would cause the main board to stop the motor and display an error message. This is a failsafe safety issue, not wanting to speed up the treadmill and hurt the treadmill user if for some reason the tachometer was defective.

    Leave a comment:


  • tool fan
    replied
    Originally posted by guylavoie View Post
    This wasn't pulse wave modulation. It was one pulse per step (two inputs, one to step faster, one to step slower). There might have been over 100 steps between zero and full speed. If there was no load (or load variation), then there were no more pulses being sent. The main board simply monitors the tachometer input which sends one pulse per rotation, and nudges the motor controller faster or slower (in reality: more or less power) to maintain the desired speed.
    I have observed similar responses to loads with less sophisticated mc 60 boards. When a load is applied at low rpm, the motor responds by delivering more power. In this case the hall effect feedback tachometer and magnet that are normally located on the treadmill have been removed. Based upon what you have reported, I have to conclude that something other than the hall effect tach cause the response.

    Leave a comment:


  • guylavoie
    replied
    This wasn't pulse wave modulation. It was one pulse per step (two inputs, one to step faster, one to step slower). There might have been over 100 steps between zero and full speed. If there was no load (or load variation), then there were no more pulses being sent. The main board simply monitors the tachometer input which sends one pulse per rotation, and nudges the motor controller faster or slower (in reality: more or less power) to maintain the desired speed.

    Leave a comment:


  • Matt Matt
    replied
    Originally posted by guylavoie View Post
    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.
    Can this be done with a three phase motors Reading the pulse wave modulation and Amps? I know some three phase motors I have a stepper counter on the backside for rotation orientation. I believe this is called sensor vector control. Some VFD’s have sensor less vector control that are only good to the number of poles the motor has. I do not know enough about DC motors, but I do know that they can have a short term burst of torque that AC motors struggle with.

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