Author Topic: ballast resistor getting hot  (Read 2076 times)

arcijack

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ballast resistor getting hot
« on: 23 July 2012, 05:46 PM »
today as i was running my 450 6.9  noticed the ballast, the white one has a very large split and both are too hot to touch, aside from crack, is it normal to get so hot that i  cant put my finger on it?

bronzy935

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Re: ballast resistor getting hot
« Reply #1 on: 24 July 2012, 07:53 AM »
I checked mine: they are warm but not too hot to hold my finger on.

TJ 450

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Re: ballast resistor getting hot
« Reply #2 on: 24 July 2012, 08:33 AM »
It could be that there is a problem upstream in the ignition system if there is excessive heat being generated. It means the coil is drawing excessive current.

Tim
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KenM

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Re: ballast resistor getting hot
« Reply #3 on: 26 July 2012, 03:56 AM »
I recently checked the resistors on my D Jet 450 after a run just for the exercise, measured with an infrared thermometer both resistors are about 98 degrees celsius on one end and about 65 on the other, so

yes too hot to touch. I'm guessing that this is normal as I have no running issues. I know my coil is good anyway.
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Tony66_au

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Re: ballast resistor getting hot
« Reply #4 on: 27 July 2012, 05:56 PM »
Old style Ballast resistors get hot, its the way they work and why they are mounted the way they are.

Basically if you were to remove the filler you would find a wire coil, usually a fairly thick gauge and the current flowing through this is creates the resistance.

A By-product of this is heat.

This type of resistor is seriously old school but serves its purpose well in what is a fairly nasty environment for componentry but they also degrade over time and after 25 or 30 years get considerably hotter as it deteriorates.

I have replaced these in a few older cars as their value (Resistance) has changed and they are usually under $20 au and Id suggest making enquiries re sourcing new units as a matter of good maintenance.

No biggie if you dont but its cheap and good practise.

Tony

arcijack

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Re: ballast resistor getting hot
« Reply #5 on: 27 July 2012, 08:34 PM »
thanks tony for the information, i changed them out today, the blue one was totally toast, thanks again for clearing that up.

Tony66_au

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Re: ballast resistor getting hot
« Reply #6 on: 28 July 2012, 06:52 PM »
No probs mate, its fairly old school stuff and often throws people off touching them.

They can cause so many hard to find niggles which is why I usually change em out to establish a baseline of stuff I can instantly eliminate as a source of trouble.

Might be worth taking pics of them though and posting them here to illustrate what and where they are, I used to have some somewhere including an old one I opened up.

Cheers,
Tony