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automotive starter and dc speed controller? Answered


can I use a 45amp digital dc pwm motor speed controller with an automotive starter? the controller is from quality kits part number :uk1133. or is there another kit  I should be using? thanks

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rickharrisBest Answer (author)2011-12-13

The car starter motor is series wound. This has 3 effects:

1. It give you a lot of torque especially at slow RPM
2. It draws a colossal amount of current at slow RPM or when stalled.
3. If operated off load the motor will go faster and faster until it self destructs.

Sadly all of these make them almost useless except for their original target use.

Your controller will never be able to handle the current.

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JWKing (author)rickharris2017-12-13

When bench testing my starters with jumper cables to see that they work I have never had one operate off load going faster and faster until it self destructed. I don't know the torque of a starter, but I do know that some of the high performance ones for sale on the net are about 3 hp

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rickharris (author)JWKing2017-12-15

You can see Steves clarification below this comment.

Under the right circumstances they will increase speed to destruction.

Either way the current makes the proposition impossible.

3HP at 12 volts gives you around 200 amps.

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steveastrouk (author)rickharris2011-12-13

3.) No, its if you turn OFF the field, it will self destruct, since there is "no" back EMF. Oh the fun we had in the EE lab at university with THAT trick.

Steve

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steveastrouk (author)rickharris2011-12-13

+1. I've seen starter currents >> 200A

Steve

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rickharris (author)steveastrouk2011-12-13

The green power racing car contest had a drag racing element for older students using a car starter, about 14 seconds of running to flatten a 12 volt battery - Sadly the batteries don't like this a lot and don't last long. You can get up to 30 or 40 MPH though in that time.

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iceng (author)2011-12-12

I don't see why a car starter needs speed adjustment.

A

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tragicallyhip (author)iceng2011-12-13

would need one if motor was being used to power a go cart or some other such thing

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iceng (author)tragicallyhip2011-12-13

The only way to control a series starter motor is to limit the current.

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rickharris (author)2011-12-13

What you really need is a old car dynamo. (NOTE NOT alternator)

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steveastrouk (author)2011-12-12

NO chance. An automotive starter can demand several hundred amps at startup.

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