Treadmill motor torque - Page 2

1. ## Re: Treadmill motor torque

VFD's under a certain size are available for 240v 1phase supply, so any double breaker of suitable rating will work, the VFD produces variable frequency, 3 phase output for the 3 phase motor.
Running a Triac controller with a bridge rectifier will work, but you may not get the performance you are expecting. May not cost much to try it..
Al.

2. ## Re: Treadmill motor torque

MC2100 PWM T.M. controllers require a 20Hz PWM control signal, If needed I have lead on necessary controllers using Picmicro and allowance for Stop/Start PB and control pot, on 50mm x 50mm board.
PM if needed.
Al.

3. ## Re: Treadmill motor torque

H All - I'm a mechanical engineer and all this electronics stuff is fascinating. I'm intrigued with the notes about a 1kw DC is not the same as a 1kw ac etc. Plus this discussion has not isolated the actual torque required to do the job or the actual torque the lathe is producing now. You need to know these things before you can design the next drive train. So I suggest you turn a pulley that you can place a flat leather belt on (or rope see attached) and some weights or a spring gauge and then you will be able to measure the actual torque your lathe can provide in its current condition at different speeds and speeds at which you want to operate. You may find its way down due to mechanical inefficiencies or whatever. Once you establish what your lathe can do then you can say I need 2x or 3x that and design your next drive system.

So if you have 3Nm, to take a figure and you make a 300mm dia pulley then you need T=Fr so F=T/r 3/.15= 20N hanging on the belt. 20N =2kg not much, a bag of sugar. This should stall the lathe. Now you have a tool for figuring out stuff vs guessing. Don't spill the sugar...Cheers Peter s

Now drive design requires the motor to overcome all the rotational inertia in the system to get to speed plus all friction components plus the job at hand. Plus it needs to be speed matched to the task. eg with a lathe if the it slows down it needs more torque as the load is going up. This is ideal for a electric motor as this is what its load/torque chart does. If the speed slows down the torque rises.

I have used 3PH motors and VFD's on machines and I like them, simple and relatively cheap what diameters are your logs? If you cut a flat spot on one of them then its ideal for a rope dynamometer.... as it also includes the job inertia...

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