Protecting a coil from overheating.

[tvr383 0]

I know that a coil can be permanently dammaged if the ignition switch is left in ON or RUN position while engine is not functionning.

It happened to me recently..and I believe it could happen to many of us specially in a period of setting up an engine..the engine dies and we forget cutting ignition off!

So I'm installing a new coil on my K-582 twin engine and wonder if there is not a kind of circuit breaker that could be installed on the wire (positive) to the coil!? I could install a small warning light that would be on while the switc is on but still it could be disregard (wife and younger kids are to use it!).

Any suggestions?

thanks.

[Save Old Iron 1,563]

showing my ignorance here - is this coil energized off a mechanical points system or electronic trigger ?

[tvr383 0]

showing my ignorance here - is this coil energized off a mechanical points system or electronic trigger ?

This has mechanical driven points system and condenser.

This system has mechanical driven points and condenser..its a K-582 twin Kohler.

[Save Old Iron 1,563]

tvr383

you may want to Google "watchdog timer circuit"

this is a little "out there" but this electronic circuit watches for a continuous train of pulses (points closing and opening) - if the pulses stop appearing at its input for longer than a specified period (say a few seconds) - then the watchdog circuit wakes up and sends a signal out to what could be a buzzer or a light to alert you.

Bad news is you will have to construct one - good news is that with even a minimum amount of electronics savvy, its easy.

The input could be to watch for the 0 to 12 volt transitions at the negative terminal of the coil - once the transitions stop - and a preset time goes by - the alarm will go off.

again, its a little out there but possible.

[oldandred 15]

yea put a timer on it and as soon as you get to cutting grass the engine cuts off thats a gread idea BUT not for me just cut the switch off or put a light on the ing side when on to remind like a yellow or green light

[Save Old Iron 1,563]

Google " watchdog timer" or " missing pulse detector" to get a better understanding of what these do - they are not egg timers

although there's another idea ......... egg timer

the only problem is forgetting to look at the light after you forget to turn off the switch

its tough getting old !! :scratchead:

[Save Old Iron 1,563]

tvr383,

just another thought - what actually destroys the coil is probably heat - so lets measure heat

there are many thermostats the size of a dime that could be strapped to the ignition coil - you would have to find a temp range somewhat but not too far above the normal operating temperature of the coil and insert this thermostat in series with the positive or negative side of the coil wire - when the coil heats up past the therm stat trip point - power is removed from the coil

same idea as some of the hydro overtemp alarms

http://www.allelectronics.com/make-a-store...REAKER/-/1.html

of course you would have to obtain the proper temp range by contacting the switch manufacturer after testing your coil under actual operating conditions.

[tvr383 0]

tvr383,

just another thought - what actually destroys the coil is probably heat - so lets measure heat

there are many thermostats the size of a dime that could be strapped to the ignition coil - you would have to find a temp range somewhat but not too far above the normal operating temperature of the coil and insert this thermostat in series with the positive or negative side of the coil wire - when the coil heats up past the therm stat trip point - power is removed from the coil

same idea as some of the hydro overtemp alarms

http://www.allelectronics.com/make-a-store...REAKER/-/1.html

of course you would have to obtain the proper temp range by contacting the switch manufacturer after testing your coil under actual operating conditions.

thanks for the ifferent options offered.The mini temp. sensor has to be put aside as it gets (as hot as the oil's own temp I gess) hot in thisarea from thw nearby twin mufflers..23 hp engine here!

The small electronic appliances based on the points cycling sounds interesting but as said I'll need to find it if it does exist!?

The warning light offers some easyer installation for sure...I'll see.

Ron.

[Save Old Iron 1,563]

here is one good example

input would be from the points - it recieves pulses as long as the engine is running

output could be to a light or buzzer - the output would stay high(+12v) until the input stops receiving pulses

the circuit then forces the output low - grounding the buzzer or light

all the parts are available at your local radio shack and the total $$ cost here is less than $5.00 - again, the downside is you either have to construct it yourself or have someone fab it up for you - probably an hour or two on the workbench

:scratchead:

[tvr383 0]

here is one good example

input would be from the points - it recieves pulses as long as the engine is running

output could be to a light or buzzer - the output would stay high(+12v) until the input stops receiving pulses

the circuit then forces the output low - grounding the buzzer or light

all the parts are available at your local radio shack and the total $$ cost here is less than $5.00 - again, the downside is you either have to construct it yourself or have someone fab it up for you - probably an hour or two on the workbench

Thanks Old Iron..I will print this a refer it to someone who knows electronics.

[linen beige 14]

If not already so equipped, put a safety switch under the seat that cuts the power to the coil when the seat is not occupied. That way even if you leave the switch on and go to the house the safety switch will still cut the power to the coil.

[Save Old Iron 1,563]

Absolutely the best and most elegant suggestion there is for this issue - as long as the switch cuts off the ignition power and not just locks out the starter bypass relay - and as long as the tractor he has actually has seat safety switches -

but from reading most of the posts regarding troubleshooting - everyone hurries to rip them out and bury them in the scrap pile - never to be seen again.

I did not want to offend anyone by suggesting they put them back into operation

I still think we do a dis-service to any new members who are reading our posts in which which actively discourage the use of safety devices, Temporary bypass for troubleshooting - no problem - never enable them again - I'll stick my neck out here and say I have five tractors - ALL THE SAFETY DEVICES WORK ON THEM. If they break, I'll personally spend the $5.00 and some quality time with my grandson to fix them.

[tvr383 0]

If not already so equipped, put a safety switch under the seat that cuts the power to the coil when the seat is not occupied. That way even if you leave the switch on and go to the house the safety switch will still cut the power to the coil.

None of that on my tractor actually,,not sure if it ever had one being a 1973 model...but for a safe usage of it ,specially while mowing,it would be an excellent device to have and its double function to protect the coil sounds simplyier to me poor ignorant in electronics!

My craftsman 4000 has one similar device,that shutt off the engine if the electric PTO is ON...the only drawback is when my lightweight 10 years son try to put the brake on he lifts himself from the seat and there goes on the device..no big deal!

Any suggestions as where can be bought one similar switch at reasonnable price?

I will check Craftsman .

Thanks again,

Ronald.