Electronics > Mechanical & Automation Engineering

10 Nm gear head motor

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I have an old round column mill, with a hand crank to lift the head for coarse vertical height adjust.

I'm thinking of replacing the hand crank with a gear head motor so I can crank it up or down with a switch from the front. I measured the required torque at 8 Nm

Any suggestions for a donor motor, I was thinking about possibly using an automotive power window (they look to have a worm style drive),  some google searches indicate torque in this range

Ideas for donor motors: power windows, windshield wiper, power seat?

Looking for ideas....

Yep you are already on the right track. Windshield wiper and window winder motors are the most common high torque geared motors.

Another source is cheep cordless drills for when you need a bit more RPM (But are not always in the form if a nice one piece motor+gearbox module)

For when you want more torque instead, electric wheelchair motors are great.

Treadmills also tend to have geared down DC motors inside, but they tend to run from rectified mains voltage (downside in terms of safety when messing with them, but upside in the power supply for it being simple and cheep)

Making progress,

I picked up a new surplus 2002-2007 Saturn Vue wiper motor today at princess Auto on sale for $13

Looks just like this:  https://www.ebay.com/itm/2002-2007-Saturn-Vue-Chevrolet-Equinox-Front-Windshield-Wiper-Motor-New-22665038-/112088295190

5 pin connector that is somewhat unclear, see image below

I found the wiring diagram, connections C, D, and E work as expected. A & B are a bit confusing
Looks like A would have +12V while the wipers are on, and then I guess +12V gets connected to the normally negative side of the motor via the park contact to stop the motor when it's in the parked position, does that make sense?

I find automotive wiring to often be more convoluted than seems necessary[attachimg=1]

Yeah looks like you just need to connect to C and D to get direct access to the motor.

The other stuff is just there to make sure the wipers return back to the default position if you turn them off mid stroke.

Nominal Animal:
For just coarse adjust, a geared dc motor – window or wiper motor – sounds the way to go.

If you want more precision, take a look at (used) NMRV-030 worm gearboxes and NEMA-23 stepper motors under microcontroller control.

I got one off eBay for a satellite tracker antenna elevation (Alaskan Arrow II).  (I don't do satellite stuff, but a friend does.)

If I were in your position and the crank can be used for finer adjust also, me being in Europe, I'd look at e.g. rattm NMRV-030 on ebay, maybe 20:1, and a dual 8mm shaft (for hand crank on the butt end just in case) NEMA 23 stepper motor (say, 23HS9440B-26), and a TB6600 stepper driver, and just about any microcontroller for generating the pulses.  I'd also use a two-step linear regulator from whatever voltage you use on the TB6600 to get the 5V to the microcontroller, to avoid motor noise causing glitches.  At 3A or so, a 24VDC supply at 4A or more should work.  The only trick on the microcontroller is to use ramping for both start and stop, to reduce wear on the gearbox.  If the stepper+gearbox has much more torque than needed, then one can assume no steps will be lost, and count the steps to calculate the distance moved. Or you could add a 5-micron scale, and read it using the microcontroller as well.


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