Alternator Help

[Bert]

I am about to start work on building a generator to charge a 12v deep cycle battery to use to power a couple of 12v halogen bulbs and a radio etc. in my remote workshop.

I'm using a 3hp horizontal drive petrol engine, a Bosch K1 alternator and I am building an electronic field controller from the design by Richard Perez, ver. 8

http://www.homepower.com/files/mark8.pdf

I believe that the internal regulator inside the alternator has to be disabled, then one of the two brushes on the alternator should be connected to ground and the second brush connects to the field output on the Richard Perez field controller.

I have made this drawing of the way I understand the connections should be, and would be very grateful if any of you guys that have had any first hand knowledge of this circuit would perhaps let me know if these connections are correct or not.

http://www.otherpower.com/images/scimages/5545/Untitled_1_copy_2.jpg

Many thanks for your time.

Bert

[Flux]

That looks fine Bert. I have never built that regulator but it looks logical and your drawing shows correctly how to connect it.

Flux

[Bert]

Thanks for that Flux.

I shall continue with the build, and hope there are not to many sparks when I switch on.

Have a good day

Bert

[Nando]

BERT:

The part LM723 ( VOLTAGE REGULATOR) for the Mark8 controller is for practical purposes not longer available since it has not been made for at least 10 years.

There are other solutions using the regular alternator regulator -- though one needs to open the regulator, and some are really sealed.

There is a lead, the one that comes form the battery and the positive side of the rectifiers that go to the regulator that sometimes can be seen into the regulator feeding a resistor string, one resistor going to a second resistor ( goes to negative lead) and from this two resistors junction a connection going to a Zener or other semiconductor.

The upper resistor coming from the battery connection can be paralleled ( from batt point to junction of 2 resistors) with another resistor at least 20 times ( if it is made variable) to control the output voltage that at the same time controls the charging current.

Also, one could use a potentiometer resistor string like the one shown in the Mark8 article and the center pot lead going to the junction of the 2 resistors -- this way one does the same control.

I am working on a regulator for the 12VDC_Power group using a TL494 device to do what you want to do in a very simple manner and with the potential of been able to set the charging mode of the alternator:

Bulk, Float, Equalize, initially done manually and later with a small microprocessor.

How soon do you need the regulator ?.

Nando

[Opera House]

If the alternator has an existing regulator, I see no reason not to use it.  You can boost the alternator by placing a 6A diode in series with the line that powers the regulator and a switch in parallel with it.  When the switch is open, the regulator will think the voltage is .6V lower than it really is and output a higher current.   In this application there shouldn't be any need beyond that.

When I see a 555 in a schematic, I know the circuit is just regurgitated garbage.  The 555 is the only integrated circuit I know that has a problematic history.  Ignoring that the circuit still has a parts count four times that of a TL494 design and a higher parts count often spells problems for a neophyte. While I agree that they should have stopped production on the 723 ten years ago, I believe it is still made.  I was corrected on another board when I made the same statement!

   

[oztules]

 yes folks lm723 regulator........its still available for 54 pence here:

http://www.maplin.co.uk/searchpages/LM723.htm

and probably a thousand places like it near you.

.......oztules

[Nando]

It may be made by some small "cooking" houses for some pocket change when the Ovens are not being loaded, the ovens use the same energy either loaded or unloaded.

The OTHER large companies have stopped making them long ago.

The TL494 still is alive because is quite versatile and it is low cost in volume and stable matured device.

Nando

[David HK]

Plenty of LM 723 IC's available in Hong Kong. I have about 6 or 7 pieces in a packet somewhere.

Let me know if you get stuck and I will post one to you.

May save you a lot of time.

dave HK

[Bert]

Thanks for that Nando, I'm not in a great hurry so perhaps i will wait to see your circuit.

Regards

Bert

[Bert]

Thanks I shall add this info to my build a generator folder.

Regards

Bert

[Bert]

Thanks for that Dave.

I have checked with Maplins UK. they have them in stock.

Regards

Bert

[Nando]

GOOD for the LM723 which was initially called UA723 by Fairchild the initial manufacturer.

Either, there are millions in stock or some small manufacturers still produce them for the die-hard small industries.

Nando