TIM 6 ignition

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Gordon

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I have two TIM 6 ignition modules on my V twin engine. They were both working but suddenly one will not fire at higher RPM. It works at low RPM but as soon as it speeds up it will not work. I assume that one of the transistors is going bad but I do not know. It is not the hall sensor because I can swap the sensors and the results are the same. Electronics is not my best field so I just blindly follow the diagram. Anyone have any insight?
 
Gordon,
My only bad experiences with the TIM 6 ignitions is that if the coil doesn't have enough resistance it will overheat the diode. Other than that they have been bullet-proof. I don't see any reason why it would fire at low rpm's but not higher. To me it sounds like there isn't enough dwell or saturation time at the higher speed and the coil can't charge.
gbritnell
 
As George has said, you maybe haven't enough dwell for the speed you require, the magnet is going past the hall too fast for the coil to fully charge when you increase the revs.

There used to be a chart with the Tim 6 kits I bought that gave you the number of 1/8" magnets required in a line for a known diameter of flywheel and the top end speed of the engine, those two things are linked if the magnets were embedded into the flywheel. I usually embedded mine into a small rotor about 3/4" diameter fitted onto the end of the camshaft and never had any trouble with just one 1/8" magnet.

If your magnet is easy to fit, then try another magnet of the same size right in line with it in the direction of rotation. This should give enough dwell time for your coil to fully charge.

John
 
The thing is that there are basically two separate ignition systems working from one magnet but two TIM 6 modules. It has worked until just yesterday. One module works and the other does not. I will try either switching the coils or try using another coil. This is cutting out at relatively low RPM like probably 50 RPM.

Slightly off from this problem but has anyone tried using the TIM 6 on 12 volts? In asking Mr Google abut this problem one site said that they were using it on 12 volts.

This engine is becoming a source of frustration. I fix one problem and another pops up on something which was fine yesterday.
 
Hi Gordon,
I guess, depending on how you look at it, that's the joy or frustration with building miniature engines. Although the internet and forums like this are great places for information some times it takes hours of tinkering to get a particular engine to run well and consistently. I personally have never run my TIM's on 12 volts. I would suggest if that is what you want to do then S&S sells a voltage regulator that can be used for a 12 volt source.
I would suspect that if the ignition and engine ran ok at one time then there might be an issue with the ignition but as far as what it might be I have no idea.
gbritnell
 
George. You are correct that the tinkering after the build is both the frustration and the satisfaction in the small engine hobby. Forums like this and others as well as internet searches are a great help when you have a problem. Frequently I have had some type of problem and after asking in a forum or doing a search I have found something which solved the problem. Frequently it is something which I ask myself why I did not think of that. Just a different perspective helps. Usually once I have everything completed it is just some simple thing which I missed. Frequently I do not even know how I solved the problem because while I was looking at one thing I also readjusted a couple of other things.
 
I am getting towards putting the TIM-6 ignition togther for my Westbury Seagull, and have several questions:

Reading HMEM, it sounds as though I am likely to get through a few Hall sensors. There seems to be thousands of them, what do I need to shop for?

(Even under my little digital microscope the markings are difficult to read but they are something like:
730S
06L
but I have not found a sensor with a designation anything like that.)

I know I must not energise it without connecting the coil through plugs to ground, but can I test the input side without the coil, ie open circuit on the output? Would that upset the voltages elsewhere in the circuit?

Does anyone know the parameters of the http://minimagneto.co.uk/Products.php Minimag Novus-2 coil I am using?
 
Charles,
When I first started using electronic ignitions a fellow had designed one that used a specific Hall sensor so that is what I use. I don't know the number off hand but if you purchase one from S&S, Jerry Howell or Minimag you should be good to go. I have used the Halls from S&S with good luck.
The one rule that is almost the 'Holy Grail' when using them is to make sure you have a good ground to the engine. If not then you will definitely short them out.
gbritnell
 
Charles,
I agree that the selection of Hall sensors seems semi-infinite, and as George says, its safest to buy one from S&S who has already gone through a selection process. If that isn't an option for you, be sure to stay away from devices listed as latching or as bipolar. My most recent experience is with the Infineon TLE4905 and you can read a little about my reasons for selecting it for my Merlin's ignition in post #385 in that build thread.
When I used the TIM-6 in my Jerry Howell engines and in my nine cylinder radial, I made a very minor change to it that allowed me to switch the voltage to the coil ON and OFF. This allowed me to set up my timing using the primary portion of the circuit including the sensor and led without worrying about triggering an accidental spark. Here is a link to its schematic

http://www.homemodelenginemachinist.com/showthread.php?t=20397&page=10
 
I talked to Roy from S&S a few years ago and he said that almost any Hall effect will work. What usually blows the hall effect transistors is a bad ground between the frame and battery. When the spark plug fires, if the grounding is not secure the voltage feeds back through the hall effect looking for ground and blows the hall sensor.

I use these, I get them on e-bay they come in from china and they cost $3.60 for a package of 10. You just have to add your own wires and plugs.

A3144, A3144E. OH3144E. Hall Effect Sensor Switches

Jim G
 
The numbers and letters on the sensor are not what your looking for apparently.
Honeywell ss 443A worked for me
 
I just pasted those numbers into Ebay and got 600+ offers.

FYI for anyone that cares, years ago Jerry Howell also sold a TIM-12 which was a 12 volt ignition. I think I still have one or two unbuilt kits laying around somewhere.

Jim G
 
The coil can work from a 12V supply with a ballast resistor to limit the current to the same value as the 6V case.
Is wasteful but the current reaches the max value faster so that less dwell time is acceptable or higher RPM are possible. If you know or measure the current I at 6V then the resistor is Rballast = (12-6)/I replace with the actual voltages you are using. The Power rating depends from a bunch of factors (dwell, DCR, actual voltages) but can not be far off with a 10W but may overheat if it sits on the spot where is ON.
 
Setting up the ignition on a multi cylinder engine provides many chances to blow Hall sensors. [experience talking.]
I managed to overcome this problem by using by using Honeywell Hall units SS443a , recommended by a forum member [thank you] and ensuring absolute earthing. Currently I have all my earthing to a common brass connector block to which is connected:-
chassis earth, the SS unit earth, and an earth wire spliced into the Hall sensor earth. From this block runs a cable direct to the battery negative. I don`t know if this set up is circuit- wise correct but the above combination has lead to trouble free firing on all four.
 
Sounds like the TIP42 chip is going bad. Check you resistance of the coils you are using. I put ballast and bring the resistance up to around 2ohm and havent had any trouble. Plus I do put a heat sink on the TIP42 When they start going bad the will work but a weak spark and will stop. Feel the chip you will feel its hot after a short run try.
 
I have the hall sensor connected to ground at the TIM-6 end, the engine block and coil primary are also grounded, but should the hall sensor ground wire be connected to the engine as well? AIUI you wouldn't normally connect it at both ends.
 
(ground = battery negative in this description).
The hall sensor should only be grounded at the TIM6 circuit board end. Not to the engine block.
And the TIM6 circuit board should be grounded with a short connection.
The engine block should be brought DIRECTLY to battery negative with a separate heavy wire.
What you are trying to avoid is any HV spark energy in the engine block from finding a path to ground other than through the heavy connection back to the battery.
If you ground the hall sensor to the block some spark energy will try to find ground through the sensor wiring which will destroy the sensor.
 
As George has said, you maybe haven't enough dwell for the speed you require, the magnet is going past the hall too fast for the coil to fully charge when you increase the revs.

There used to be a chart with the Tim 6 kits I bought that gave you the number of 1/8" magnets required in a line for a known diameter of flywheel and the top end speed of the engine, those two things are linked if the magnets were embedded into the flywheel. I usually embedded mine into a small rotor about 3/4" diameter fitted onto the end of the camshaft and never had any trouble with just one 1/8" magnet.

If your magnet is easy to fit, then try another magnet of the same size right in line with it in the direction of rotation. This should give enough dwell time for your coil to fully charge.

John
Here's a link to the TIM6. It mentions Dwell Angles: Transistor Ignition Modules
 
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