Author Topic: TY250a CDI  (Read 372 times)

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Offline Nide1

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TY250a CDI
« on: April 13, 2021, 07:47:29 pm »
[attachimg=1]
I'm trying to fix this CDI off a motorbike for a friend, but I can't identify this component, any help would be very much appreciated.
Sorry about the scratch I had to dig it out of resin.
Can somebody tell me how it triggers without a trigger coil?
Thanks
Nide1
[attachimg=2][attachimg=3]
 

Offline perieanuo

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« Last Edit: April 14, 2021, 11:26:21 am by perieanuo »
 

Offline Nide1

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Re: TY250a CDI
« Reply #2 on: April 14, 2021, 02:08:41 pm »
Thanks for the reply perieanuo, I thought it must be SCR.

Can anybody tell me how to work out gate current/voltage in simple layman's terms.

Thanks, Nide1.
 

Offline perieanuo

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Re: TY250a CDI
« Reply #3 on: April 14, 2021, 04:47:24 pm »
gate voltage here is irrelevant, gate current is given i guess by the ignition coil vie 1u5 cap, rectifier diode and 86ohm//diode and 1k resistor, and the zener limits the peak
i didn't do any calculations, but there are 'normal' gate current scr's and more senzitive ones, i think a normal one will do the trick, like i pointed before
see https://uk.farnell.com/c/semiconductors-discretes/thyristors/thyristors-scrs
the normal ones are like 8-10mA senzitivity on gate, either you use a 'normal' either a <1mA one, but my bet is it's a regular one, in that environement a sensitive gate is not desired if you design such a thing, automotive is noisy and threshholds are generous
« Last Edit: April 14, 2021, 04:50:57 pm by perieanuo »
 

Offline Nide1

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Re: TY250a CDI
« Reply #4 on: April 14, 2021, 07:41:55 pm »
Thanks again perieanuo, I'll get a 2N6509G and give it a go, I've tested everything else in the circuit so we should see a spark.

To buy one  which comes with stator plate will cost a 100 to 200 pounds and he said he always liked how the engine ran, so worth doing.

Thanks again.

Nide1.
 

Offline perieanuo

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Re: TY250a CDI
« Reply #5 on: April 15, 2021, 01:15:20 pm »
ok, just please keep us informed
 

Offline Nide1

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Re: TY250a CDI
« Reply #6 on: April 17, 2021, 07:29:39 pm »
Hi,

I fitted SCR(BT151-500R) and it worked like a dream, the best spark he had ever seen.

So thanks again perieanuo.

He's got to sort the carb/fuel out, but I've done my bit.

Thanks
Nide1    :-+ :-+ :-+


 

Offline perieanuo

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Re: TY250a CDI
« Reply #7 on: April 19, 2021, 06:48:33 am »
you're welcome, glad to hear it works, you can now press thanks to my post :)
best regards, pierre
 
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Offline Nide1

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Re: TY250a CDI
« Reply #8 on: April 19, 2021, 08:09:24 pm »
I thought I put a picture of the bike.
 
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