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Installation of Rotec alternator

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Installation of Rotec alternator

Postby wolfcub1945 » Wed May 06, 2020 7:23 pm

I am installing a Rotec alternator kit in my CH601XL that has a Jabiru 3300 engine. I have run into a couple of problems and am seeking help on two issues:

1. The Jabiru alternator that is now in the plane has two ignition coils that have wires that connect to the two distributors. When these are removed to allow for the installation of the Rotec kit, there is no longer a connection to the distributors. Without current to the distributors, the engine will not start. Moreover, the installation instructions for the Rotec kit provide no advice on this problem. Any thoughts on how to deal with this issue?

2. The installation instructions for the Rotec kit specify that the magnetic ring that is aft of the flywheel needs to be removed and the drive pulley installed in its place. I have removed the four button head screws that serve to hold the magnetic ring in place. However, the ring does not come off. Any advice on removing it?

Thanks, in advance, for any help you can provide.

Gene
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Re: Installation of Rotec alternator

Postby Steevo » Wed May 06, 2020 7:36 pm

I am a little confused. There is no physical link between the original Jabiru stator (alternator) and the distributors.

There is a lead that goes from each coil to the distributor cap. These have to remain.

I assume you are only installing the Rotec alternator and not the electronic ignition upgrade that Rotec also make for the Jab as well (they did offer a package that contained both).

If you are not installing the electronic ignition as well, then the original coils, leads and distributors will remain albeit mounted on a different spider.

I used to have the manual for the Rotec but cannot find it now but certainly the coils and their leads remain. Either the manual isn't clear on this or it is assuming the electronic ignition is being installed as well.

The stator has probably just stuck itself on there as 620 locktite is often used to put the button head screws in and some of it sometimes gets under it. Try some heat from a hairdryer and it should come off.
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Re: Installation of Rotec alternator

Postby wolfcub1945 » Wed May 06, 2020 8:08 pm

Thanks Steevo.

Note that I am only installing the alternator kit. On the Jab 3300 there are two ignition coils and there are leads that run from these to the distributors. I can leave these in place, but wonder if they will power the ignition system. The reason is that in the Jab 3300 setup, the coils appear to be activated by the magnetic ring. So, once the ring is removed I don't know if there will be current to the distributors. It may well be the case that I am wrong about how the distributors are powered. If so, please let me know. Many thanks!

Gene
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Re: Installation of Rotec alternator

Postby Steevo » Wed May 06, 2020 8:19 pm

The coils are activated by magnets on the flywheel itself. The stator magnets and spider play no part in energizing the coils. The flywheel isn't being removed so there will be no disruption to the ignition system apart from the coils having to be mounted on a new spider contained in the kit.

I have not installed the Rotec alternator but did put the Camit kit on my older Jab. It was the best upgrade I ever did. But the principles between the 2 are the same.

If you look on the outside edge of your flywheel, you will see magnets opposite each other. These are the magnets that energize the coils. These should not be removed. You will, however, have to reset the gap to about 10 thou when you move your current coils to the new spider.
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Re: Installation of Rotec alternator

Postby wolfcub1945 » Thu May 07, 2020 1:15 pm

Thank you very much. I was under the mistaken impression that the coils were activated by the magnets in the magnetic ring. So, your information is most helpful. Thanks again!!!!

Gene
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Re: Installation of Rotec alternator

Postby diablo » Thu May 07, 2020 2:01 pm

The jabiru ignition system is very simple. It is essentially the same system that is used in lawnmowers. It does not require power. Two sets of magnets are attached to flywheel. As the flywheel rotates, the magnets swipe past the coils generating a current. The coil acts like a transformers and amplifies the voltage many times over (low to high voltage) which is fed to the appropriate spark plug via the distributor and bang, fuel is ignited and off you go!

see diagram which should be self explanatory ...

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Re: Installation of Rotec alternator

Postby wolfcub1945 » Fri May 08, 2020 12:07 pm

Thanks Diablo!

I now have a better understanding of the operation of the ignition system.
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Re: Installation of Rotec alternator

Postby paulhorth » Wed May 13, 2020 10:44 am

You will find that the six cylinder (3300) engine has three sets of magnets on the edge of the flywheel and the four cylinder only has two.
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