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I have a project where I have to sweep a windshield wiper about 90° at a rate of 150 sweeps/minute. (~3 sweeps/second)

Since the sweep rate is high, I was thinking of using a stepper motor to get it done.

I will get the specs of the wiper soon after which I may be able to estimate the voltage,current and torque requirements.

But I need advice regarding the motor and driver choice since the project timeline is short and we cannot afford to make mistakes.

Edit: I'm a bit inclined towards a stepper motor due to it's speed and sweep controllability, though will it be able to accelerate and decelerate the load at such a high rate?

Edit: I realise that the windshield link mechanism to convert rotational motion into sweeping one would be a much better approach and a brushed DC motor would do the job nicely. So the only challenge remaining is getting enough torque and rpm out of it.

P.s I checked some wiper motors, they have 55 rpm with 40 kg-cm torque

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    \$\begingroup\$ Stepper is an option. Back of the envelope: 120 degrees sweep = 240 degree round trip. 3x / second => 720 degrees/second motion. => 400steps/sec with standard 1.8deg stepper. Not much room in steps/second for gear reduction, maybe factor of 2-2.5, so it will be a question of torque vs motor size... \$\endgroup\$
    – Pete W
    Feb 16, 2021 at 16:18
  • \$\begingroup\$ IMO: DC motor. Steppers are for precision control which you don't need. BTW I believe car windshield wipers actually drive the motor in one direction and use a mechanical mechanism to make the wiper go back and forth. \$\endgroup\$
    – user253751
    Feb 16, 2021 at 16:58
  • \$\begingroup\$ I saw the mechanism, you are correct \$\endgroup\$
    – nalostta
    Feb 16, 2021 at 17:12
  • \$\begingroup\$ Have you investigated the potential use of windshield wiper motors? Either ones designed for an airplane or a car? I met an aircraft mechanic once. To replace a small metal plate he had to make a plan, citing relevant procedures and rules, sign out exactly the materials required, affect the repair according to procedure, and then complete documentation. He could spend several hours on a plate, a few tubes of goo and a dozen "cherry rivets". After talking to him, it seems like you might be at risk of half-assing the design of an aircraft. \$\endgroup\$
    – K H
    Feb 17, 2021 at 4:34
  • \$\begingroup\$ @KH it's for a movie shoot \$\endgroup\$
    – nalostta
    Feb 17, 2021 at 5:43

2 Answers 2

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3 sweeps per second means that you are going to be spending a large part of the time accelerating the wiper. You need to build this into your torque calculation and it will lead to a requirement for very high starting torque.

A series wound DC motor will probably be most suitable for this.

You have not told us where your requirement has come from, perhaps a rotating glass clear view screen would be more suitable.

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  • \$\begingroup\$ We are trying to implement the windshield wiper of an airplane. I'm inclined towards a stepper motor because of the speed and the angle control. Otherwise I'd have add in extra measures to check the sweep angle as well \$\endgroup\$
    – nalostta
    Feb 16, 2021 at 16:49
  • \$\begingroup\$ Just out of curiosity, they actually do small series wound motors? Up to about 0.5kW I only see permanent magnet ones. Or are you maybe talking about universal appliance motors? \$\endgroup\$
    – Lorenzo Marcantonio
    Feb 18, 2021 at 12:45
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'Real' windshields (car ones, at least) usually use DC brushed motors with gear reductions and cam switches.

Stepper motors are fine but be careful since they lose torque really quick when driven fast. I actually have no idea on the mechanical torque needed for the application.

I would use a BDC motor with maybe some form of encoder feedback to do such a thing. While they are somewhat less popular gived the rise of BLDC I think that the brushed DC is still very suitable in many application

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