Can't locate part: need help or further replacement

Thread Starter

jeka616

Joined Jan 14, 2009
131
Debe,

thanks for pulling this info for me.

I did locate some BOSCH parts yesterday, however.. here is the situation. I'm attaching the current hook up schematic of bike's regulator. So...below are regulator types that I was able to find datasheet so far

- 78H12 (5A) - case is common...doesn't match up, my opinion

-LT1038 (10A)/LT1083(5A)/LM138 (5A) - I think this is what installed in original, as pinouts match as per your explanation, i.e. the output is fed to input throught the rotor...or am I missing something? This is the tricky part to sort....

- LM396 (10A) is another variation, and also to me is not applicable.

Need to get around this...

p.s. all, pls post all the regulator types that you are aware of and are capably of >=10A, and as per 2nd bullet regulators pinouts.
 

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debe

Joined Sep 21, 2010
1,389
Unfortunately what you are looking at are 3 term regulators, these are not suitable as altenator regs. Am altenator regulator feeds current to a rotor to generate voltage out of the windings. The resulting voltage generated is sensed by the regulator, this then controls the amount of current fed to the rotor. This is in a constant feed back loop. The device you have in the orig reg is NOT a 3term volt regulator. It is a custom made altenator regulator totaly different.
 

Thread Starter

jeka616

Joined Jan 14, 2009
131
I see...I was just getting online to order LT1083...thanks to your explanation, did stop. I think I need to get back to builing desk and make one that you suggested.

Another guestion is, to modify BOSCH regulator, and find correct pins, which I already did. So will plug in tonight, see what happens..

Thanks. I'm very glad to be a member of this forum, where experienced in electronics people are habitating. Alghough I visit seldom, but always getting quality feedback.

Later...
 

debe

Joined Sep 21, 2010
1,389
Which Bosch reg are u using? The one I posted in post11 isnt suitable with out altering the Rotor circuit. If you want to use the original altenator circuit use post17.
 

Thread Starter

jeka616

Joined Jan 14, 2009
131
I've got one exactly looking like you posted, in post 20, from BMW. I will test that tonight. If it doesn't test, I'll build the latest you suggested.

but I do not know the rating of BOSCH 3 pin metal case regulator...
 

Thread Starter

jeka616

Joined Jan 14, 2009
131
all right, I got good news)

I did hook up the BOSCH regulator, as per Debe's last schematic...however it did not work..I was upset..then I noticed that, although it came from BOSCH alternator, it had BERU brand name on it..so took time out to investigate connection/pin outs. Here is the attached diagram, of correct pinouts for BERU. And....it worked:) The battery voltage fluctuates now between 12.5 - 15v, which is acceptable...before it was goint up to 21V at 11.500 rpm...

Here are some pics of my testings.

Great thanks go to user DEBE, who explained the details of how alternators are functioning nowdays. Without him, I almost purchased visually same, but internally totally different stuff.

At the end, thanks to all for support. Later...
 

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