Help on wiper motors.

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bezzy
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Help on wiper motors.

Post by bezzy »

Hi a am thinking of building a bigger coin pusher but am unsure how i would control a wiper motor, what current do they draw and what type of power supply would be needed, would 12v wired to a switch not work? does it have to be hooked up to some form of controller? must be as simple as possible as my electrical knowledge is limited. Many thanks.
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badpenny
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Re: Help on wiper motors.

Post by badpenny »

Glittering Prize may be along shortly, I think he started by fiddling with wiper motors before progressing to meatier stuff, he may be able to advise you. He is a master when it comes to self build

12 volts isn't a lot of juice and a shelf supporting a stack of metal coins has to overcome a fair bit of friction. Starting and stalling torque.
In a commercial pusher the most expensive (apart from the modern ones which have computer management) is the motor and gearbox which are the same sort they use in kebab rotisseries in take-aways.
Apart from using one with enough grunt and a suitable power unit you also need to be aware of "continuous rating"
Continuous rating and short-time rating
A time rating is used to express the time during which the motor can normally output the rated power. Continuous
rating indicates that the motor can provide the rated power during this period. The short-time rating indicates that
the motor will reliably operate to produce the rated output for the relatively short time specified.
You will want "continuous rating" as you won't want everything getting too hot, possibly bursting into flames ...... burning your wooden case ..... oh lordy there goes the dining table and the curtains are smoldering now. All guaranteed to hack off SWMBO and generate hilarity at your house insurance company as they point out all of the reasons they won't pay out.

Check it out on Wiki and you'll understand how to read the jargon they put on the manufacturers' plates on electric motors

BP
bezzy
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Re: Help on wiper motors.

Post by bezzy »

I have come across this on ebay it is 12v 30Rpm and has a torque rating of 1225Nm i think thats a lot? would it not be just a case of hooking up to a 12v supply and switch?
chris roadhog
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Re: Help on wiper motors.

Post by chris roadhog »

12v will work for very short periods but no good for continuous running. You need a 220/240v brushless, geared motor to be right.
steinslots
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Re: Help on wiper motors.

Post by steinslots »

Although wiper motors are cheap and plentiful they will require a large 12v power supply, which will add to the weight, heat build-up and electrical consumption because transformers are only like 30% efficient, unless you use a switched-mode power supply (80% efficiency).

It's best to use the traditional mains geared motor. Like the ones they use on slush puppy machines, chocolate fountains and other commercial catering machines.

Here's an example, although 10 RPM is a tad slow: http://uk.rs-online.com/web/p/ac-geared-motors/2483643/
wb
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Re: Help on wiper motors.

Post by wb »

Microwave oven motor perhaps? I cheated on my coin pusher when I found a Flippa Winna motor in an arcade that I did bits for.

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JC
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Re: Help on wiper motors.

Post by JC »

Here's an example......
Actually Carl, that's not a great example. Shaded Pole motors, particularly geared motors are quite commonly not continuous rated - as in this case, which clearly states an operating rating of 20 minutes.
steinslots
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Re: Help on wiper motors.

Post by steinslots »

Yep, well spotted! It was a rubbish example.

That'll teach me not to post on forums during meetings at work!
Last edited by steinslots on Thu Dec 22, 2016 1:39 am, edited 1 time in total.
glittering-prize67
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Re: Help on wiper motors.

Post by glittering-prize67 »

Hi,
For a start you need brushless motors, and AC for continuous use. A wiper motor needs a lot of amps and on 12 volt you will need a huge transformer. Shaded pole is best - they are silent and draw little current, as used by most companies in the sixties and seventies.You can get continuous rated and geared to about 15 or 20 rpm. Induction motors can be used and these are a standard motor from Japan and you simply buy the gearbox you want and four bolts hold it on the motor. If you really want to be adventurous, you can use a geared stepper motor, but these do require a driver p c b. Microwave motors are not strong enough and are not designed to run for that long.
richie
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Re: Help on wiper motors.

Post by richie »

I am currently considering a wiper motor also but for a different application as I had set up an induction motor that used a gearbox but was still rotating too fast so I tried both a rheostat and current limiting module that both failed. To use an induction motor that will have the correct rpm's for your application you need to use a variable frequency drive, and these aren't cheap.
Another concern/issue may be the mounting of the 12V motor.
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