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Dynamo regulator - tips for revival?


Timleech

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9 hours ago, WotEver said:

Dynamo regulators work by black magic (that’s why they’re that colour) and they hum to themselves...

They sound quite friendly!

 

Reasons for keeping the dynamo are:

Cost - a new one is very expensive

The existing dynamo works - if it ain't broke...

We have two complete running engines so have a spare of everything.

The dynamo is geared drive from the flywheel and engine revs are 900-1200 - changing to an alternator would necessitate a new drive system and mounts all adding complexity and uncertainty to a seagoing vessel.

The owner wants simplicity and authenticity.

 

The only broken thing we have is the voltage regulator and sourcing a 24V voltage regulator for a dynamo is proving difficult. If we could get a modern reliable electronic 24V dynamo voltage regulator it would make a lot of headaches go away.

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18 hours ago, john4647 said:

This may help.

 

https://www.ebay.co.uk/itm/362982127782?autorefresh=true

 

See diagram on pictures supplied in the listing.

Hi John. In the original thread you mentioned a solid state version of the 189A used by the diesel train fraternity. Might that be the elusive replacement that would solve my problems?

 

Andy

 

Edited by AndyW
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How much is the work to convert to electronic regulation going to cost? I bet its far more then £90 Ebay are quoting for a 24V A127 (far from my favourite alternator). I know nothing of the engine but I know a number of alternators driven off an exposed flywheel and some don't even have a machined groove in the flywheel for the belt.

 

I don't know what the field current is for the dynamo but I do know a typical alternator regulator only switches between 3 and 4 amps on 12V machines. If that was enough I think a remote alternator regulator might work as long as its switching frequency (very high compared with dynamo regulators) did not cause problems. Trouble is they are listed at oner £100 and then you have to work out how to connect it. If a diesel train one is known to work its probably the best bet if you can find one at a price you are willing to pay, if not then anything except changing to an alternator would have an uncertain outcome unless you can find someone who has done it. If you did use an alternator regulator on the dynamo you would still have to fit a cut out to stop the battery discharging through the stationary alternator.

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I found the PDF file of the 189A. Please see PM sent to OP.

 

The extra coils are probably field resistors but I am not sure, without seeing it. In any case the PDF will give you the mechanical & electrical settings, there is a table on the last page which covers your dynamo.

 

Not seen the solid state regs for many many years but they were fitted to trains.

 

Regards, John

Edited by john4647
tryping errot
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On 19/06/2020 at 16:09, john4647 said:

Wiring diagram shows field to Pos regulation and dual field circuits.

So does this mean a positive earth system?

 

Looking through the workshop manual there seems to be a + and - connection for everything so maybe this question is irrelevant. As it is a marine installation there is no common earth as there would be on a vehicle.

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4 minutes ago, AndyW said:

So does this mean a positive earth system?

 

Looking through the workshop manual there seems to be a + and - connection for everything so maybe this question is irrelevant. As it is a marine installation there is no common earth as there would be on a vehicle.

Normally, for marine applications (and many others) this would be an insulated return system, as long as the dynamo is insulated return.

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Thanks John,

 

It looks like the dynamo is insulated return as it has four connections marked +, -, F1 and F2.

 

We're beginning to think that the regulator is OK so fingers crossed it all might work when it is hooked up.

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On 19/06/2020 at 20:11, Tony Brooks said:

 

I think some Merc vans had a ready made system. As the 2 x 12V batteries you use to provide 24 volts will only be put in series when starting the split charging should be easier. May be 2 VSRs.

 

How vital is it to keep the dynamo? I think a 24V alternator would be easier all round ans I think SirN may have  a similar view.

Agree on both counts. The dynamo output would be pretty puny with only half voltage to the field. Google for an AC7 alternator and that should fit straight into the mount for a DO7, presuming a strap mounting. Alternatively engineer a mounting for belt drive and the world's your bivalve mollusc.

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Dear all!

I have an old ship with a diesel engine and a 24v system. There's a separate CAV control board (regulator) type 189A-7 and a generator. Problem is that these are disconnected.

Could you please send me the PDF manual?

Best wishes

Jonas

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13 hours ago, k24jj said:

Dear all!

I have an old ship with a diesel engine and a 24v system. There's a separate CAV control board (regulator) type 189A-7 and a generator. Problem is that these are disconnected.

Could you please send me the PDF manual?

Best wishes

Jonas

Hello,

PDF sent by PM.

Pity there is not a section on the site where we can post manuals and the like, for everybody to access. (Larger than 2.93MB)

  • Greenie 1
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2 hours ago, john4647 said:

Hello,

PDF sent by PM.

Pity there is not a section on the site where we can post manuals and the like, for everybody to access. (Larger than 2.93MB)

I'd like a copy of that for my reference library if you don't mind. I get a fair bit of vintage stuff to deal with.

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On 02/07/2020 at 10:17, Sir Nibble said:

I'd like a copy of that for my reference library if you don't mind. I get a fair bit of vintage stuff to deal with.

Apologies for the delay, only just picked this up.

Will send by PM

 

Well... can't do that either, max size is 2.93MB, PDF file is 4+MB. Can't send zip files either.

PM me with your email address please.

Edited by john4647
as above
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  • 5 weeks later...

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