Wiper motor 12Vcc - how to reduce speed

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Hi,
What is The simplest way to control the speed of a wiper motor working at 12Vcc?
The ideal would be controlling the speed from zero up to its maximum with a potentiometer.

Pwm? Or what else?
Have a schematic diagram to share with me would be great

[budm]

Re: Wiper motor 12Vcc - how to reduce speed

Read through some of the links.
http://www.robotshop.com/forum/showt...eed-controller

http://www.societyofrobots.com/robot...?topic=14293.0

http://www.electro-tech-online.com/t...sserie.114681/

http://www.practicalmachinist.com/vb...-254464-print/

http://hackaday.com/2013/05/16/alter...your-projects/

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Re: Wiper motor 12Vcc - how to reduce speed

Great!

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Re: Wiper motor 12Vcc - how to reduce speed

What about the following solution?

[budm]

Re: Wiper motor 12Vcc - how to reduce speed

555 as the PWM, that looks like it will work, just have to make sure the MOSFET can handle the surge current of the motor, it should also be mounted on the heatsink.
Experiment with it will be the thing to do.

[_max_]

Re: Wiper motor 12Vcc - how to reduce speed

5A is the max current driven into the motor. I guess a MOSFET 80V 25/30A @ 25°C should do the job.
Does the diode in parallel to the motor need to be special Shottky ?

[budm]

Re: Wiper motor 12Vcc - how to reduce speed

Is 5A the continuous current draw? The start up current can be much higher, how high I do not know for your motor.
The BY Diode is for reducing the motor kick back voltage down to safe level to protect the MOSFET and voltage kick back into the power source, it has to be high voltage, 1000V rating will be fine, http://www.rapidonline.com/electroni...diodes-528282/
Some info about suppressor for the motor
http://www.kemet.com/kemet/web/homepage/kfbk3.nsf/vaFeedbackFAQ/7A55FDCC2F01F2DE852579ED00501068/$file/2011%20CARTS%20-%20Broadband%20Interference%20Suppressor%20Modules.pdf

http://www.picaxeforum.co.uk/showthr...-for-DC-motors

http://forum.allaboutcircuits.com/sh...ad.php?t=44500

http://www.learningaboutelectronics....VS-circuit.php

http://www.electronicspoint.com/tran...r-t132127.html

https://cdn.badcaps-static.com/pdfs/...325e9262a5.pdf

[_max_]

Re: Wiper motor 12Vcc - how to reduce speed

Is 5A the continuous current draw? It start up current can be much higher.

Actually 5A is the maximum current expected, in standard conditions at maximum speed the amperometer reads 1.7A

The BY Diode is for reducing the motor kick back voltage down to safe level to protect the MOSFET and voltage kick back into the power source, it has to be high voltage, 1000V rating will be fine, http://www.rapidonline.com/electroni...diodes-528282/

I see. The only doubt remains about the torque, if it drops to zero at very low speed...

[budm]

Re: Wiper motor 12Vcc - how to reduce speed

Torque of the motor:
http://electronics.stackexchange.com...-motor-via-pwm
Another thing is the frequency of the PWM, I cannot find the info I have, http://electronics.stackexchange.com...-of-a-dc-motor

http://www.societyofrobots.com/membe...xport/html/234

[Longbow]

Re: Wiper motor 12Vcc - how to reduce speed

Why not include a bit more information about the project? Are you actually designing this circuit for use in your vehicle, or just tinkering with a spare motor? PWM control of a d.c. motor assumes that you know the load requirements. A wiper motor is probably shunt-wound, which is designed for near constant speed operation. As such, you will need to apply nearly full voltage for starting. Most practical PWM motor control circuits are closed loop. Motors that do not have an internal frequency generator can be sensed by looking at the commutator noise, for the purpose of starting and running in closed loop mode.