# Wiper Motor- Moves like a stepper motor with some walwarts



## drzeus (Jun 25, 2011)

Hey Guys, I have a question;
I recently purchased a couple of wiper motors from Monsterguts.
using 3 out of the four walwarts that I have available, the wiper moves as though its a stepper motor, ie; intermittent, slight movement.
It works fine with a high dollar radio shack unit (WAY TOO COSTLY).
One of these walwarts is a "universal" converter. If I quickly change from a low voltage, back to, say, 12volt, the motor will run fine for a few seconds then go back to the intermittent motion.
All outputs are dc (according to their perspective labels).
Does this have something to do with regulated vs. unregulated, or am I missing something quite obvious?
I have been having some TIA's lately. Maybe I should retire before someone gets hurt!... LOL

Any help would be suggested.

(PS: I just ordered 2 LED dimmers via Amazon for $6 bucks apiece to regulate the voltage. I will report when I receive them tomorrow (Tuesday).

Thanx!!


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## hedg12 (Jul 6, 2008)

How many amps are the wall warts rated for?
A wiper motor is pretty forgiving as far as voltage variance goes, but they do need some current to get them moving - I'd suspect the wall warts don't have the oomph to get the job done.
I'm guessing the LED dimmers you ordered are PWM dimmers. They don't actually vary the voltage - they switch the current off and on many times a second, and vary the "on" time in relation to the "off" time. They will work fine to vary the speed of the motor.


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## Victor (Sep 4, 2011)

Try reversing the leads. I found that is what my motor did when I had them backwards.


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## HomeyDaClown (Oct 3, 2009)

Those Radio Shack universal wall warts are only rated at about 0.3 Amps (300 milliamps) and that is probably conservative. The other problem is that they are not regulated or filtered very well. When you hook them to a big load like a wiper motor the voltage drops way off and what is left is low voltage pulsing DC.

A good place to start is a 5 volt 1 amp regulated wall wart (very common/inexpensive for cell phones and computer equipment) , doubt you'll find one at the Shack though but many to be had online. I have several running wiper motors straight up (at a reduced speed) and they work fine.

A wiper motor under any load can draw 5 amps easily, so 300 milliards is not going to get you much as you already are experiencing. Most likely that wall wart will get hot and die a quick death.


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## drzeus (Jun 25, 2011)

Thanks guys. The amperage does make the most sense.
Monsterguts website states that the motors only require 2 amps at 12 volt under full load, but I would tend to agree with your assessment.
Each of the warts I used was rated at at least 2 amps. 
Funny thing is, the one that.worked properly was only rated at 1.5.
Gonna go buy some Monsterguts walwarts!
Thanks guys!

Just as a follow-up, I thought I should post that the PWM from Amazon doesn't work adequately.






It does do what it should, adjust the rpm's, but the motor emits a really annoying scream at anything other than its highest setting.
Unless you have some very loud background noise, it would be very obvious and annoying.
Isn't gonna work for me.


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## Lunatic (Oct 3, 2006)

I've run a wiper motor for my kicking legs using a 1.5 amp 12 volt supply. It ran okay but would overheat in about an hour and shut off. Never experienced intermittent before. I went with a computer power supply.


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## hedg12 (Jul 6, 2008)

The hum from the motor is from the PWM controller pulsing the current to the motor & the windings actually vibrate. Won't hurt anything, but very annoying.


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## HomeyDaClown (Oct 3, 2009)

It's the total power output capacity in watts that makes things go. Amps X Volts = Watts. I suspect the 1.5 amp wart has a higher voltage and therefore better power capacity. 

Those are chinese LED dimmers and are basically very cheap PWMs for Led lighting. Leds don't have wire windings so they never make any noise. Motors will make noise from PWM supplies just like a speaker unless the PWM frequency is higher than you can hear. Higher frequancy PWM units are bit higher priced too.


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## dazgill (Aug 7, 2012)

just one other thing you may want to "tinker" with...when you say your motor is only working intermittantly.......i am not sure of the monsterguts wiper motors as i usually get mine from a car breakers yard, so this is a general wiper motor commentthere are usually several connectors on a wiper motor, all of which are used by a car to perform various functions such as high speed, low speed, intermittant, once etc.the usual way to connect a supply to the motor is to connect the negative to the case (there is usually a connection on the case of the motor) and then the postive (or live) to one of the connectors dependant upon your needs.trial and error as to which is which is the only way to find out.


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