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Old 03-09-10, 03:54 PM   #11
metalmagpie
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Default Wico A

Thanks for that, I bought one a few weeks ago.I fear that they are reprints of David Edgingtons copy of a very basic manual. They don't show anything of the Impulse, nor even an exploded view to gauge what goes where?
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Old 03-09-10, 04:13 PM   #12
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I am sure one of mine has, If not there its the wolseley wd engine book that shows it
I will have a look when I get home

pmc
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Old 03-09-10, 09:19 PM   #13
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Default wico magneto

I would be very grateful, there isn't much information about.
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Old 04-09-10, 11:40 AM   #14
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Originally Posted by Jezmiester View Post
Ok question.

I have a mag and it sparks a lot at the points when running and im suspecting the condenser. This particular mag the condenser is burried and difficult to get to. I was wodering could a new one be added into the circuit without removing the old one, or will this have a detremental or no effect, or could this solve the problem.

Any thoughts.

Jez
Yes, as long as you use the correct value and a type designed for the fast-rising voltage spike which appears across the points.
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Old 04-09-10, 11:43 AM   #15
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Originally Posted by metalmagpie View Post
Thanks for that, I bought one a few weeks ago.I fear that they are reprints of David Edgingtons copy of a very basic manual. They don't show anything of the Impulse, nor even an exploded view to gauge what goes where?
I have lots of info on the Wico A mag and intend to put it into a booklet when I have time. However, most of it is included in the maintenance manual for the Douglas SV engine, available from the website.
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Old 04-09-10, 11:46 AM   #16
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Hi,

A condensor is just a capacitor, so yes you could fit a new one without physically removing the old failing device. But you would have to take the old one out of circuit, that is disconnect it electrically. Otherwise you would be fitting 2 capacitors in parallel, if you do this then the size of the plates within double. So it follows that the value of the capacitor also doubles, this would have a deterimental effect on the spark.

Cheers, Gerry.
The sparking will be due to the original capacitor having " lost" its ability to act as a capacitor, thererfore it will display no capacitance and will have no value, thus should be ok to leave in circuit.
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Old 04-09-10, 12:29 PM   #17
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thats most intersting diagram and infomation ,thanks for sharing mate
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Old 08-09-10, 10:14 PM   #18
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The sparking will be due to the original capacitor having " lost" its ability to act as a capacitor, thererfore it will display no capacitance and will have no value, thus should be ok to leave in circuit.
Hi, I just found this forum doing some research while fixing a Wico magneto.

Sorry to butt in like this with my first post, but i don't think it is a good idea to leave a dead condenser in circuit. It is possible that capacitor failure will be due to a broken connection inside the capacitor itself, but the cause of failure is far more likely to be that the capacitor has gone "leaky". A capacitor consists in effect two metal plates seperated by an electrical insulator. What tends to happen especially with older caps is that the insulator fails. Testing conductance across the capacitor with a meter isn't good enough as the insulation may break down only with a large voltage applied.

If you simply connect a new capacitor in parallel then the leak is still there, you might get away with it in the short term as the overall capacitance increase might counteract the effect of the leak, but the faulty cap will no doubt degrade further before long. The old condenser can remain but snip the wire as it enters.

In my mag I decided not to replace the faulty condenser with a NOS (and possibly suspect) replacement but instead borrowed a trick from vintage audio repair, stuffing a modern high voltage capacitor into the shell of the old condenser (so everything still looks authentic!) after first gutting the dead cap
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Old 09-09-10, 09:23 AM   #19
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Originally Posted by stimpy View Post
Hi, I just found this forum doing some research while fixing a Wico magneto.

Sorry to butt in like this with my first post, but i don't think it is a good idea to leave a dead condenser in circuit. It is possible that capacitor failure will be due to a broken connection inside the capacitor itself, but the cause of failure is far more likely to be that the capacitor has gone "leaky". A capacitor consists in effect two metal plates seperated by an electrical insulator. What tends to happen especially with older caps is that the insulator fails. Testing conductance across the capacitor with a meter isn't good enough as the insulation may break down only with a large voltage applied.

If you simply connect a new capacitor in parallel then the leak is still there, you might get away with it in the short term as the overall capacitance increase might counteract the effect of the leak, but the faulty cap will no doubt degrade further before long. The old condenser can remain but snip the wire as it enters.

In my mag I decided not to replace the faulty condenser with a NOS (and possibly suspect) replacement but instead borrowed a trick from vintage audio repair, stuffing a modern high voltage capacitor into the shell of the old condenser (so everything still looks authentic!) after first gutting the dead cap
It is not just the voltage rating of the capacitor which is important, but also its maximum rated "rate of rise" of the applied voltage which it can tolerate. This is what kills most condensers in this type of application. There are very few capacitors in the normal "electronics supply chain" which meet this requirement, particularly within the size constraints (with an impulse type magneto, the switching spike can be of the order of 20,000v per micro second)
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Old 10-11-10, 01:06 PM   #20
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Default wico magneto

Thanks for all your advice. Guess what? the Magneto was an anticlockwise one and the timing marks on the flywheel were marked for a clockwise rotation. I could not see how to alter the mag to clockwise so I retimed it with the engine running anti clockwise. All is now fine.
Thanks again
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