# Wiper Motor Speed Control



## phil121 (Oct 25, 2009)

Thanks for creating this thread, its very useful. Do you think this speed regulator unit would work just as well http://www.maplin.co.uk/Module.aspx?ModuleNo=9312

thanks

phil


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## thisain'tmayberry (Jan 25, 2010)

If I'm reading the specs on that unit, it looks like it would work, however the performance envelope is much narrower vs. the Qkits model; Maplin unit 6-15v input, 3amp output vs. Qkits unit 12-24v input, 15amp output. A wiper motor under heavy load could draw more than 3 amps but (hopefully) not more than 15 or you would probably be poppin' circuit breakers!


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## phil121 (Oct 25, 2009)

Oh i think it should be ok, its just for a tomstone peeper using a foam head.

Thanks thisain'tmayberry your great 

phil


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## phil121 (Oct 25, 2009)

You seem to know your stuff , could you possibly answer this question for me. If i have a 12vdc power supply rated at 0.5 Amps lets say, and i hook it up to a speed regulator such as the one you suggested 
would the wiper motor still work even though the amps from the 12v power supply were alot lower than the 15 amps coming from the speed regulator ?

thanks

phil


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## thisain'tmayberry (Jan 25, 2010)

Amps are like gas in your car. You can't run down the highway at 55 (haha) with only enough gas to keep the engine at idle. The engine needs more gas to make the car go faster. A V-8 engine uses more gas than a 4 cylinder engine. If you try to run a V-8 on the same amount of gas as a 4 cyl. you won't be able to tow a heavy load, take advantage of any of the power of the engine and might damage it. Why would you spend the money to buy a V8 if you intend only to use it like an econobox?

A wiper motor is kinda like a V-8. If you "step on the gas" in the form of driving/moving/lifting a heavy prop, the motor will require more "gas" which are amps. Starving the wiper motor with too little amps is equivalent to the example above. If you're "coasting down a hill" you only sip gas, with a light prop, no load, etc. you will "sip" amps. If you're "powering up a hill", you gulp gas; likewise with the wiper motor. It could draw a significant number of amps. Scary Terry (http://www.scary-terry.com/wipmtr/wipmtr.htm) once measured a wiper motor pulling 14 amps!

In my opinion, a .5 amp (or 500 milliamp, same thing) power supply is inadequate for a wiper motor, if you're using a wiper motor to drive a prop in the first place.


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## phil121 (Oct 25, 2009)

Although im not old enough to drive yet and know nothing about engines :L
i still get your point

thanks 

phil


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## dsw (Sep 11, 2011)

Trying to get a unit like Qkits unit 12-24v input, 15amp output this but from the UK, anyone know where in the UK i could get one, i don't have paypal or ebay account so i cant use the option, i have looked cant seem to find any... 

Cheers
DSW


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## dsw (Sep 11, 2011)

Ok I think I have Found what I'm looking could someone confirm this is right
http://www.quasarelectronics.com/3166v2-bidirectional-dc-motor-speed-controller-5-32vdc-10a.htm

Cheers
DSW


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## thisain'tmayberry (Jan 25, 2010)

That unit should do nicely. What are you using for a power supply?


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## dsw (Sep 11, 2011)

Computer power surply that be good won't it ?


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## thisain'tmayberry (Jan 25, 2010)

Plenty good, that's what I use. I actually mounted my speed controller inside the power supply box. Nice and tidy.


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## Scary Papa (Jan 31, 2012)

I also have an idea for a speed control for a wiper motor. I just go to radio shack and buy reostats. They run about $4 and I have used them on my wiper motor driven props for 4 years now with no problems at all. Just a thought.


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## CreepyCreations (Oct 16, 2011)

Those speed/motor controllers will give you far better results and control over the motor. I'd be wary of a reostat, only because it slows the motor down by limiting the current (usually by turning the excess into heat).
PC power supplies and speed controllers is the way to go, especially where wiper motors are concerned. They can draw a fair bit of current.


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## Scary Papa (Jan 31, 2012)

CreepyCreations, you are correct and I guess I should have made my comment a little clearer. I wasn't saying that using a reostat or potentiometer was better that using speed controllers that are designed for these applications. I was just commenting that as an alternative and cheaper setup for very limited applications such as what I use them for the 12v reostats that I have used worked very well for the last few years. Of course I haven't used the wiper motor/reostat combination for heavy applications either. Just for moving arms or turning heads on figures or moving an animated pirate ships wheel.; no heavy loads. And I would not reommend their use for anything more that these types of light load applications. For those who can afford them and for heavier applicatons i certainly agree the motor controller really is the best.


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## CreepyCreations (Oct 16, 2011)

Scary Papa... hey, I'm all for keeping the costs down! LOL using a reostat for lower power applications would probably work just fine. Most of our applications tends to be a little more "heavy duty" (doors, flinging scares, jumping rats, robot arms that actually lift things, dropping skeletons, etc) so I either just let the motors run full speed (lots of fun during testing, let me tell you!), or use a solid state controller.


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## gusbud1 (Mar 3, 2011)

I've found some of these motor controllers on ebay for a good price ($6-$7) shipping included. The ones I've picked up have worked great for my caldron creep and my coffin opener. Just search New 12V-40V 10A Pulse Width Modulation PWM DC Motor Speed Control.


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## Old Man Bakke (Oct 18, 2011)

Does anybody know where to get a 12 V 5 amp Wall adapter / Wall Wart to power the wiper motor? I have looked around and cant seem to find one. I don't want to use another CPS mainly because its to bulky.


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## Halstaff (Nov 8, 2009)

Old Man Bakke said:


> Does anybody know where to get a 12 V 5 amp Wall adapter / Wall Wart to power the wiper motor? I have looked around and cant seem to find one. I don't want to use another CPS mainly because its to bulky.


Monster Guts has them at http://monsterguts.com/index.php?act=viewProd&productId=11


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## Old Man Bakke (Oct 18, 2011)

Yeah I have seen that one....but for 19 bucks...idk


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## gusbud1 (Mar 3, 2011)

If you search for NEW 12 Volt DC Power Supply 5 Amp on Ebay it pulls a couple up for $10.00-$8.99 with free shipping. I searched on Amazon for 12 V 5A DC power supply and it came up with one for $2.99 with $6.00 shipping. It also lists 48 watts in the header, I don't have enough electrical knowledge to know if that matters or if its primarily the 12 V and amperage that matters. If someone could answer that, that would be helpful to me.


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## Old Man Bakke (Oct 18, 2011)

Now that is what I am talking about! Very reasonable in price and you got to love free shipping!

Thanks gusbud1


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## budude (Jan 3, 2010)

gusbud1 said:


> It also lists 48 watts in the header, I don't have enough electrical knowledge to know if that matters or if its primarily the 12 V and amperage that matters. If someone could answer that, that would be helpful to me.


Wattage = Voltage x Amperage - so if it says 48 Watts and it's a 12 volt supply, that means it will supply 48W / 12v = 4 Amps.


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## CreepyCreations (Oct 16, 2011)

Gusbud1/budude: I find it odd that a power supply supposedly rated at 12 V @ 5 Amps says it's 48 watts. Maybe I need to go back to math class, but last time I checked 12 * 5 = 60, not 48. However, I would play it safe and assume you can, at best, get 4 Amps out of it. That should still be more than enough to run a wiper motor. Just be warned, though, that the startup current for one of those motors can quickly spike well above that. It's a very brief spike, and most power supplies can handle it, but some can't. Make sure there's a return policy if you are ordering online, and order early so you can try it out and, if necessary, send it back and find something else well before you need to have things done. Nothing worse than discovering something isn't working the day/night before!


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## Joven76 (Oct 5, 2012)

Question about power supplies. I have a 12V/2A power supply. Is that too weak for a wiper motor or should I look into one with more amps?


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## budude (Jan 3, 2010)

CreepyCreations said:


> Gusbud1/budude: I find it odd that a power supply supposedly rated at 12 V @ 5 Amps says it's 48 watts. Maybe I need to go back to math class, but last time I checked 12 * 5 = 60, not 48.


Many times the cheaper PS vendors may just cut/paste specs so it's not too surprising to get mismatched numbers like this but the formula is correct.


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## thisain'tmayberry (Jan 25, 2010)

Joven76 said:


> Question about power supplies. I have a 12V/2A power supply. Is that too weak for a wiper motor or should I look into one with more amps?


It depends on what you're trying to move. 2 amps may be plenty for a light weight prop or a short throw lever. Scary Terry once put an amp meter on a wiper motor and watched it draw *13 Amps* trying to lift a weight . The motor will only take what it needs, but it can need a lot depending on what you're asking it to do. Describe what you have in mind and you'll get a more definitive answer.


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## Joven76 (Oct 5, 2012)

I'm thinking of a FCG to start with, but I'm toying with the idea of having it hold a lantern. So it might be a bit heavier than a normal FCG. Also, can any wiper motor work, or should there be a specific automotive make/model?


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## thisain'tmayberry (Jan 25, 2010)

I run a pretty heavy FCG using a wiper motor and an ATX computer power supply with the qkits speed controller. The wiper motor had enough torque to lift the prop but the action was jerky, i.e. slow up/fast down. I counter-weighted the prop to smoothe the action and it has been running flawlessly for 11 years.


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## Joven76 (Oct 5, 2012)

Well, I'm on my way to building one of these set ups, but I have another question regarding the ATX power supply. I've noticed a lot of different supplies out there with varying wattage. What would be the best fit for a FCG?


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