Vevor sewing machine motor as power source

[matthewsx]

Thanks, I already have the motor and it worked fine except for the stock mounting.

It’s a CNC project so eventually want to control the spindle in software. If it turns out not great I’ve got less than $100 into it and would be looking for another small servo.

Here’s that project.

Homemade vertical mill drill

Well, I guess I'm gonna try to make myself a mill for cheap. I found this column on Craigslist for $80. And I ordered this spindle I can power with a VFD I already have. And I'm going to get one of these cheap x-y milling tables. And probably look for a really flat piece of C channel...

www.hobby-machinist.com

John

 

[homebrewed]

Looking at the data sheet, you should be able to replace that sensor with a pot and one or two resistors. The sensor output ranges from 1 to about 4.2V (see page 3, VH and VL values).

When turned on, the controller checks to see if the speed control is plugged in, that's why you get an error message. It probably looks for the right current flow drawn by the sensor, 6.5 milli-amps, or (more likely) for an output voltage that's at least 1V. To keep the controller from going into an error mode you will need to reproduce one or the other with the resistor network. There was an earlier thread on this forum discussing the same kind of thing for a Consew motor, if you want to do something similar. Not knowing what the sensor's VCC is, I can't give you any resistor values at this point.

The controller also should go into an error condition if it sees an excessively-high control voltage. This would prevent a too-sudden application of speed, given the context of protecting the operator of the sewing machine when first starting the machine. The controller is programmed to "think" in terms of possible faults -- an open supply pin OR an open ground pin. One fault condition would produce zero output volts, the other something close to VCC. An open Output pin would look the same as an open VCC so that's covered as well.

Finally, the motor speed may not be all that linear with respect to a control voltage -- the magnetic field produced by the magnet attached to the foot pedal may not vary in a linear fashion w/respect to position. I'd be surprised if it did. If you're looking at a set and forget application that probably is not a big deal. If not, there are ways to sorta-kinda address that but it would mean you'd need to make a more complicated circuit to do it.

 

[whitmore]

... the motor is so quiet I have to look at the pulley to see if its running.

That probably means it's a brushless motor, probably three-phase. That implies you can reverse it, as well
as control the speed (swap any two drive wires with a DPDT switch).

On the sensor, there's red/yellow/black wires; see if (when powered) there's +5V on red and grounded black.
Then, it's just a matter of how to connect the yellow wire... and try to find a Hall sensor with the numbers
you see on the chip (I can't quite read 'em).

 

[fitterman1]

That probably means it's a brushless motor, probably three-phase. That implies you can reverse it, as well
as control the speed (swap any two drive wires with a DPDT switch).

On the sensor, there's red/yellow/black wires; see if (when powered) there's +5V on red and grounded black.
Then, it's just a matter of how to connect the yellow wire... and try to find a Hall sensor with the numbers
you see on the chip (I can't quite read 'em).

Hi whitmore, i think it is brushless, i want to do away with the hall effect sensor and replace it with a on/off switch.

 

[fitterman1]

I think I'm going to encapsulate the module and magnet in a small junction box and arrange the magnet in a permanently fixed position with some hot melt glue or silicon. Then cut the output wire and run the leads to a small switch.
This will be my realtime on/off switch.
This way I can adjust parameters without the unit running and test at the flick of a switch.

 

[matthewsx]

Definitely brushless. I like this approach, will have to look into it.

John

 

[fitterman1]

Yes, look into it, no brushes = less maintenance.