Puma / Dorman 6LE / MacFarlane B46B / 110 kVA Generator Resurrection

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awemawson:
Late (workshop) start today due to Porcine Processing, three dismantled fattened pigs having been delivered at 7:00 this morning as IKEA self assembly kits. The commercial butcher that I use cocked up so when I went the two hour round trip yesterday morning to collect, they hadn't been done :bang: Steam issuing from my ears convinced him that him delivering today was a 'good idea' :clap:

So, back to work - still waiting delivery on some vital bits for the engine block heater (which I'm having to fabricate) so . . .

I refitted the charging alternator mounting bracket, the alternator itself, and the three new fan / drive belts which I'm glad to say seem to be correct.

Having done this it was time to investigate alternator regulators. The machine came with a CAV440A , the replacement charging alternator came with a supposedly working CAV440D and I also obtained (again supposedly) another CAV440D as 'new old stock' in a CAV cardboard box.

All were in pretty awful condition with loads of muck, paint and corrosion. I decided to lightly sand blast the CAV440A which at least allowed me to unscrew it's screws to open it up.

I'd not usually take such drastic action against innocent bits of electronics, but I think that it was justified in this instance! I've read somewhere that the 440D version is 'improved' in that it clamps one of the inputs in the case of faults but I'm struggling to find the refeerence.

So, the 440A had one Lucar connector virtually corroded away, the others have cleaned up well enough that I can re-tin them to stop further corrosion.

All fairly straightforward inside, only really two mystery components - a blue and white block that I think must be a thick film resistor circuit, and one of the three NPN transistors is unmarked. As the other two are 2N3055 and BFY50 I'd be surprised if the unmarked one is not a BC109 or very similar.

Comparing resistance values at the Lucar terminals of all three units they are remarkably similar, so it is actually possible that they all work !

More web hunting to find that reference to the 440D variant - if it proves sensible I may clean one of them up and uses it, otherwise I'll have to replace the riveted male Lucar on the 440A that's so badly eaten away (probably electrolytically)

awemawson:
Found it - a US web site:

"The type 440 regulator has three setting depending on the rate of charge required in certain circumstances:
HI – Setting for normal ambient temperatures.
MED - Setting for countries with high ambient temperatures where there is a risk of battery overheating.
LO - Setting for countries with high ambient temperatures where there is battery gassing. Once batteries have
cooled the setting must be returned to MED or HI.

Initially the 440 regulator was fitted, but was superseded by the 440A that could work at higher temperatures.
Both types had the disadvantage that should the connection to the LO, MED or HI terminals fail then too high a
voltage will be given out resulting in excessive alternator output. The 440D, which is directly interchangeable
with the earlier regulators, has a fail-safe arrangement. In the event of a similar fault the output voltage is held
down."

Read more at http://www.ybw.com/forums/showthread.php?260872-Battery-Charging-System-Help-Required-To-Understand/page2&s=c9f86ab41675f20586bc5700b1919f2b#O4RPPR0gII7CcFOc.99

awemawson:
After supper I had a go at re-tinning the Lucar connectors on the CAV440A. Not come out too badly, certainly functional, but there is deep pitting in places stopping full wetting. I left the badly corroded terminal strictly alone.

Then I gave the 'new old stock' CAV440D a light blasting - no significant corrosion on this one - the light blasting didn't even have to remove the tinning so I suspect it's declared 'NOS' status is probably true.

The other CAV440D that came with the new charging alternator has one terminal (MED) in a very similar poor condition to the CAV440A that had the High terminal corroded.

I understand that these regulators switch the field at a reasonably high frequency and this has probably contributed to the terminal corrosion seen.

Comparing the internals there is very little difference between them, a few resistors and an extra diode.

So the 'New Old Stock' regulator wins the beauty competition and is the one I will initially install, holding the others in reserve in case it doesn't work.

awemawson:
I decided to give the CAV440D regulator a coat of paint before installing it to stop it's casing going all furry like the others - not Bling I promise you :clap:

It actually had three coats of acrylic can paint with accelerated drying under the workshop hot air hand drier - this dryer gets used far more for this than hands - I prefer a towel !

The real job of the day is to make a new water jacket heater. I've not been able to source a replacement for the original so need to make one. I had a 1" copper bar to hand, a 1" BSP male/male nipple that is through bored 26 mm, I'd ordered a 1" BSP Stop End cap, and a 10 mm cartridge heater 50 mm long 250 volts 200 watts and had to hand a 20 mm male conduit nipple to give a wiring connection point so we need to set too.

I wanted to get the 25.4 mm copper bar to be a snug fit in the 26 mm male/male nipple prior to brazing, and had hoped that knurling the copper would squeeze it out enough to swell by the 0.6 mm needed, but it was just too loose, so in the end I made up a brass shim packer with dimples to hold them concentric as heat was applied.

awemawson:
So I cut a slice off the 1" copper bar, faced it, and bored it out 10 mm leaving a 4 mm wall at the far end.

Then fitting my packing shim I set too with the oxy-acetylene, got a bit over enthusiastic trying to ensure full flow of the braze, and manged to melt the end of the 1" BSP male / male nipple - Oops :bang:

Never mind, probably recoverable - so I mounted it up on the lathe, skimmed it back to good brass and ran a 1" BSP die nut down it - the threads on the nipple were too long anyway so I don't think that this will be a problem.

A good old clean up, then I bored out and tapped the 1" BSP cap to take a 20 mm conduit nipple, which I screwed in and sweated in to stop it unscrewing. The original heater has an integral ceramic terminal block, but the new has flying leads, so a terminal box will fix onto this 20 mm conduit stub.

Altogether not perfect but I think that it will do the job.

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