Rotax Type "A" Dynamo Regulator.

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Stan Thomas
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Location: Penkridge. Staffs.

Rotax Type "A" Dynamo Regulator.

Post by Stan Thomas » Wed Apr 11, 2018 2:34 pm

Does anyone have any factory info regarding wiring diagram or setting and adjusting the Rotax Type "A" regulator as fitted to some late 20's and early 30's cars?

Mine "cuts in" at too high a voltage - but I'm adamant not to depart from originallity and fit anything else!

Simon Hyslop
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Re: Rotax Type "A" Dynamo Regulator.

Post by Simon Hyslop » Wed Apr 11, 2018 9:08 pm

Hello Stan. I have consulted all the old books I have and none of them show this regulator, they all start at about 1933. However, I am going to take the liberty of making some guesses here and hope they may be of use to you. At that time, the regulator should be just a cut-out unit. The actual voltage output would be controlled by a third brush in the dynamo.

Therefore, the cut out unit of any make should contain only one fairly simple adjustment to vary when the dynamo cuts in or out of the charging circuit. Usually this is a screw with a lock nut. Whatever sort of cover is on your Rotax unit, after taking it off, assuming it comes on and off ok, there should be a winding with a fixed contact and a moving contact which is sprung. The adjustment screw should be connected with that moving contact and by carefully moving it up or down, the point at which the dynamo cuts in and out should be altered.

The only thing really to watch for is that the cut in speed and voltage is about right , at about 1000/1200 rpm and 14 volts at the dynamo when cold.

As I say, this is based on general 3rd brush practice so apologies if Rotax did something different but within the limits of electrical technology at the time, I'm struggling to see what they would have done radically different. Hopefully, anyone who knows more will write and add to our knowledge.

Stan Thomas
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Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Rotax Type "A" Dynamo Regulator.

Post by Stan Thomas » Thu Apr 12, 2018 9:46 am

Firstly, thank you for taking the trouble to post a lengthy reply Simon - much appreciated.

What you say makes perfect sence - but - rather stangely, yes I have a three brush dynamo - but no - it has a two coil regulator such as would be used on a two-brush system - (and it may also have a third winding to limit current output). Hence the confusion.

It may well be the factory were mix-and-matching components, which was not uncommon in those days to "use up" old stock - so have concocted the charging sytem somewhat. This is certainly true of the ignition system - which has both an auto-advance distributor and a manual control on the steering column - simply because the latter was earlier stock, with the drivers' handbook saying to keep the manual lever in the full advance position!

I'll look into it further and perhaps one of the libraries may be able to help. - but thanks again for your response.

Petelang
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Re: Rotax Type "A" Dynamo Regulator.

Post by Petelang » Thu Apr 12, 2018 10:05 am

Can you post photos of the device Stan. Interested to see what it is you have.
It's forty odd years since I was a sprog at Joseph Lucas but it might fire up some long dormant brain cell somewhere....?
Peter
Peter Langridge
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Stan Thomas
Posts: 364
Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Rotax Type "A" Dynamo Regulator.

Post by Stan Thomas » Thu Apr 12, 2018 7:11 pm

Will do Peter if you can give me a few days.

Stan Thomas
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Joined: Sat Feb 13, 2016 2:14 pm
Location: Penkridge. Staffs.

Re: Rotax Type "A" Dynamo Regulator.

Post by Stan Thomas » Wed May 02, 2018 8:31 am

Hi Peter,

Sorry I have not been back in touch after you kindly offered assistance, but a "family problem" has prevented me having time to even look at the Daimler (hope it's still there!).

Basically, it requires too high a voltage to energise the solenoid to pull in the cut out - and some previous owner has put 24v bulbs in the warning light!

What intigues me is that there is a second solenoid/armature which in the normal course of events would suggest a two-brush dynamo with current regulation - but my car has the correct three-brush dynamo and "off-on" switch arangement on the dash to turn off charging. Hence my query.

However, I will come back to you in due course given your kind offer of help.

Regards,

Stan.

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