# Vevor sewing machine motor as power source



## fitterman1 (May 5, 2022)

I'm using an industrial sewing machine motor for driving a dbit grinder which is nearly completely rebuilt.
The motor is vsd controlled, which made sense to me, being perfect for a sewing machine.
It came with a controller which is easily mounted under the worktable.
A power lead plugs into supply (240vac), another plugs into the controller for motor supply and a third is for the pedal speed function.
The pedal speed unit control looks like a transistor being influenced by a magnet which moves past as the pedal is pressed.
Is anyone familiar with this setup as i want to change this to an on/off switch, but don't understand what is going on with the small module and the magnet?


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## benmychree (May 5, 2022)

Variable speed is of little or no use for a D bit grinder.


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## fitterman1 (May 5, 2022)

Yes, you're right but I can control the spindle speed, braking, and ramping in the parameters. This way I can specify optimal sfm for the grinding wheel.


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## matthewsx (May 5, 2022)

I have one I’m about to put back on my mill/drill project. Definitely interested in how you control the speeds.

John


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## homebrewed (May 5, 2022)

If it's a magnet moving past a "transistor", it isn't a transistor.  It just about has to be a linear hall-effect sensor.  It could look like a transistor -- it would have Ground, Vcc and Output pins.  It just needs three terminals, that's why it would look like a transistor.  If so, it wouldn't be all that difficult to replace with a potentiometer and (most likely) a little voltage divider network.  The reason for the voltage divider network:  the hall effect sensor's output range may only be a few tens to some hundreds of millivolts, while the Vcc input could be 3-5V (or more).  Just trying a pot would likely produce a result that behaves like an on/off switch.

Getting the part number off the sensor and finding the data sheet will help speed you on your way.  Otherwise you're looking at some additional experimentation to get it right.  A couple of tandem-connected pots would help there:  route the wiper pin of your lower-ohm pot to the top of your higher-ohm pot.  The bottom pins would be connected together as "ground".  The top pin of the low-ohm pot (say 1K) would go to Vcc.  The wiper pin of the high-ohm pot (say 10K) would go to the Output connection.  The top pin of the low-ohm pot would be connected to Vcc.  Once you get everything set up, you adjust the high-ohm pot to set the motor speed.  You'd start by adjusting the high-ohm pot so its wiper is connected to its top pin, then adjusting the low-ohm pot so the motor is running at your maximum-desired RPMS.

The reason I'm talking about low-ohm and high-ohm pots is that the pot connected to the other one's wiper will load it down, causing difficulties with regard to linearity.


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## fitterman1 (May 6, 2022)

I'll pull the small board out and get a number off the "hes" when I get home.
The motor powers the spindle quite easily for a 550W unit. Standstill to 4500rpm is instantaneous in response.
Parameters are easily adjusted within the menu, which I like and the motor is so quiet I have to look at the pulley to see if its running.


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## fitterman1 (May 6, 2022)

homebrewed said:


> If it's a magnet moving past a "transistor", it isn't a transistor.  It just about has to be a linear hall-effect sensor.  It could look like a transistor -- it would have Ground, Vcc and Output pins.  It just needs three terminals, that's why it would look like a transistor.  If so, it wouldn't be all that difficult to replace with a potentiometer and (most likely) a little voltage divider network.  The reason for the voltage divider network:  the hall effect sensor's output range may only be a few tens to some hundreds of millivolts, while the Vcc input could be 3-5V (or more).  Just trying a pot would likely produce a result that behaves like an on/off switch.
> 
> Getting the part number off the sensor and finding the data sheet will help speed you on your way.  Otherwise you're looking at some additional experimentation to get it right.  A couple of tandem-connected pots would help there:  route the wiper pin of your lower-ohm pot to the top of your higher-ohm pot.  The bottom pins would be connected together as "ground".  The top pin of the low-ohm pot (say 1K) would go to Vcc.  The wiper pin of the high-ohm pot (say 10K) would go to the Output connection.  The top pin of the low-ohm pot would be connected to Vcc.  Once you get everything set up, you adjust the high-ohm pot to set the motor speed.  You'd start by adjusting the high-ohm pot so its wiper is connected to its top pin, then adjusting the low-ohm pot so the motor is running at your maximum-desired RPMS.
> 
> The reason I'm talking about low-ohm and high-ohm pots is that the pot connected to the other one's wiper will load it down, causing difficulties with regard to linearity.


What would be reading the hes?
Could it be possible to bypass this and have the main controller only?


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## fitterman1 (May 6, 2022)

Yes it is a "hes"
Here's the data sheet.


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## fitterman1 (May 6, 2022)

Tested without the hes plugged in brings up a fault on the display which means I have to bypass it somehow.


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## fitterman1 (May 6, 2022)

matthewsx said:


> I have one I’m about to put back on my mill/drill project. Definitely interested in how you control the speeds.
> 
> John


John, I've picked this motor because it has the necessary torque to spin up a grinder spindle quickly. The only speed control required is for different sized wheels. This I can change in the parameters, if necessary.
I would go for a dc motor for what you want, a potentiometer speed controlled unit would provide excellent torque especially for milling. I use a treadmill motor on my G0602 lathe and it works great.


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## matthewsx (May 6, 2022)

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


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## homebrewed (May 6, 2022)

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.


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## whitmore (May 7, 2022)

fitterman1 said:


> ... 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).


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## fitterman1 (May 8, 2022)

whitmore said:


> 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.
> ...


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.


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## fitterman1 (May 14, 2022)

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.


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## matthewsx (May 14, 2022)

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

John


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## fitterman1 (May 15, 2022)

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


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