# Help my wiper motor - Stirring cauldron



## Devils Chariot (May 23, 2007)

I am building a cauldron stirring prop. I bought this motor on saturday










Here is the link to the product page:
http://www.allelectronics.com/make-a-store/item/DCM-249/POWERFUL-WINDSHIELD-WIPER-MOTOR/-/1.html

The problem I am having is this.

Scary Terry sez :"Current. The minimum required current for the motor is 1.6 amps at 70 rpm, 0.9 amps at 41 rpm (and 4 amps if you elect to run it at 106 rpm, see note on the next page).

So I got a 12v 1.4 amp 120ac/dc converter wall wart. I wanted it to go slow, so I didnt get a 5 amp which I thought I had have to put a dimmer switch on to turn down the juice (That's probably a bad idea but I don't know that.)

When I tried to hook it up I only got a clicking noise. I tried all the combinations, nothing, nothing, nothing, clicking sound, but no motor movement.

Also of note, there are two identical rows of power inputs on this thing.

Like this, only times 2.:










Anyone know what I am doing wrong?


----------



## Dr Morbius (Sep 21, 2004)

My guess is your wall wart may be the culprit, assuming you have tried all combinations of wiring. Test it on an ATX computer power supply and see if it makes a difference. If not, you got a bad motor. Maybe someone knows more about the wiring of this particular motor, I don't have one like it, but in case you didn't read it already, here is the data sheet on it.
http://www.allelectronics.com/mas_assets//spec/DCM-249.pdf
After looking at it, it looks like it requires BOTH +12v DC and -12v DC. Weird. Don't know what it means...unless it's for just the one revolution stops-in-the-same-place-it started option. Looks like it needs 2.5 amps no load, meaning I still think your wallwart is the culprit.
I DO know that the specs Scary Terry gave is the min current needed for the speed options on a particular motor depending on how it's wired. The motor will only use the current required to run and no more, so the more available current you can supply, the better. Meaning current doesn't determine how slow or fast the motor goes, voltage does. Up your current, and I'll bet it'll work.


----------



## Devils Chariot (May 23, 2007)

Thanks Doc, I still haven't finished "Electronics for Dummies". No really, I haven't.


----------



## Dr Morbius (Sep 21, 2004)

No prob, just remember lower the voltage to go slower, but give it all the current you can.


----------



## Dr Morbius (Sep 21, 2004)

Here's a great product for controlling wiper motors from Monsterguts:
http://www.monsterguts.com/electric-motors-for-props/pacemaker-wiper-motor-controller/prod_163.html


----------



## Devils Chariot (May 23, 2007)

yeah yeah i know. Maybe I will just break down and buy it. 

Say i did use a dimmer switch, that limits the current yes? If voltage is like how much water you can hold in a tank, then current is how fast you can drain it?


----------



## Dr Morbius (Sep 21, 2004)

I don't think you can use a dimmer switch on a DC circuit, since the triac relies on the alternating current in an AC circuit to make it switch off little or most of the cycle depending on how much voltage is allowed to pass through the gate of the triac by a variable resistor. You CAN use a variable resistor by iself in a DC circuit, but again that just limits voltage. That may or may not work with wiper motors, I never tried it, but it does work with DC circuits in general.


----------



## Troy (Oct 14, 2006)

Check All Electronics Website for a wiring diagram, that motor needs two grounds for some reason, trust me this very thing drove me crazy for 2 days last year....All you need to do is run a seperate ground wire from your walwart and away it will go. I use the same motor in my cauldron.


----------



## Devils Chariot (May 23, 2007)

Troy said:


> Check All Electronics Website for a wiring diagram, that motor needs two grounds for some reason, trust me this very thing drove me crazy for 2 days last year....All you need to do is run a seperate ground wire from your walwart and away it will go. I use the same motor in my cauldron.


Do you meant like this?










Or does one of the grounds go somewhere else?


----------



## Fetch (May 16, 2008)

I'm using that exact motor in the prop I'm building.
(See this thread: http://www.hauntforum.com/showthread.php?t=11412)

I tested several voltage/current combinations, and found that anything less the 7.5v won't move it. You have to hook it up with power to pin 1 (top left), ground to pin 2(bottom left) THEN split off the same ground and connect it to pin 5 (3rd pin from left, top row) to provide the switch current that will start the motor. Keep in mind you have to keep pins 1 and 2 connected to power and ground continuously, and use pin 5 as the "switch". I'm using a 12v 1.5amp wall wart, and it works fine.

Hope this helps.


----------



## Devils Chariot (May 23, 2007)

*It take a village, and then some...*



Fetch said:


> You have to hook it up with power to pin 1 (top left), ground to pin 2(bottom left) THEN split off the same ground and connect it to pin 5 (3rd pin from left, top row) to provide the switch current that will start the motor. Keep in mind you have to keep pins 1 and 2 connected to power and ground continuously, and use pin 5 as the "switch".


Is this right?


----------



## jabberwocky (Apr 30, 2008)

I believe this would be pin #5 marked with orange.


----------



## Troy (Oct 14, 2006)

Sorry I can't see the pics here at work what I did was cut the ground wire from my walwart and splice another piece of wire to the one I cut...the other end of the second ground wire I attached to one of the top mounting holes omn the motor (I used hose champs to mount my motor) after doing the above I was able to run this motor as low as 3 amps. 7.5 would cause the stirring to be too fast IMO. 

If you have any other question PM me and maybe I can help you over the phone.


----------



## Fetch (May 16, 2008)

Jabberwocky's pic is the correct hookup.

Troy, are you using the DCM-249? I wasn't able to get mine to consistently run on less than 7.5v @ 2 amps.


----------



## Troy (Oct 14, 2006)

Fetch, yep thats the one...it ran for about 3 weeks at 3v @ 2 amps?? I bought 4 of them.


----------



## Fetch (May 16, 2008)

Thanks, Troy. I may have to try your method of grounding to the mounting holes for the extra motor I bought to replace a bad one on my FCG. It was too fast before, even at 7.5v.


----------

