12V Bosch Generator - Exploded Diagram

[Jolls]

Hi Team

I pulled down the Bosch generator today and checked all the internals were OK. It appeare a bit loose around the shaft when I did my initial inspection - like there was a bearing on the way out. So I opted not to "motorise" her to see if she was in corking condition.

When I stripped her down I found some of the insulation had deteriorated; however, the insulation built into the field windings still appeard to be intact (no shorts to earth). I gave the damaged /failing areas a coat of liquid electrical tape.   The bearing and bearing fit seemed fine so I was puzzled as to the "loose" feel. On closer inspection it appears that there may be bits missing - the odd felt and wavy washer around the bearing and potentially a couple of thrust washers/shims to get the preload correct.

Does anyone have an exploded view of the Bosch generator - the manual has the Lucas one and there are enough differences to make it "not very useful".

Cheers n Beers
Craig

[ardiesse]

Craig,

The later FE-FC manual has an exploded diagram of the Bosch generator, as do the FB and EK manuals.

The felt and wave washer have probably been removed because the ball-bearing was replaced with a double-sealed type.

When you say "loose around the shaft", what do you mean?  Axial end float, side-to-side movement at the commutator end (sintered bush), or side-to-side movement at the drive end?

The field coil insulation in the Bosch generators is paper, and it's common that it falls to bits.

The major hassle with Bosch generators is replacement brushes.  Bosch stopped making them years back.  The aftermarket part number is BS754, and Ashdowns still has a few sets.  Except that they don't sell retail - you need to find a co-operative auto electrician to order them.

Rob

[Jolls]

Craig,

The later FE-FC manual has an exploded diagram of the Bosch generator, as do the FB and EK manuals.

The felt and wave washer have probably been removed because the ball-bearing was replaced with a double-sealed type.

When you say "loose around the shaft", what do you mean?  Axial end float, side-to-side movement at the commutator end (sintered bush), or side-to-side movement at the drive end?

The field coil insulation in the Bosch generators is paper, and it's common that it falls to bits.

The major hassle with Bosch generators is replacement brushes.  Bosch stopped making them years back.  The aftermarket part number is BS754, and Ashdowns still has a few sets.  Except that they don't sell retail - you need to find a co-operative auto electrician to order them.

Rob

Hi Rob

I was referring to end float.

The bearing is not a sealed type, but I will replace it with one given I appear to be missing some of the parts. My manual must be the early one - I do have a Gregory's manual - didn't think to look there.

Cheers n Beers
Craig

[ardiesse]

Craig,

There'll be a spacer missing.  I had the same problem with one of zulu's generators.

Working your way toward the front of the armature, there should be -

Inner Splash Ring
bearing inner race
intermediate ring
pulley and Woodruff key
lock washer
armature nut

I reckon the "inner splash ring" was helpfully thrown away by the last person who "reconditioned" your generator.

Rob

[Jolls]

Craig,

There'll be a spacer missing.  I had the same problem with one of zulu's generators.

Working your way toward the front of the armature, there should be -

Inner Splash Ring
bearing inner race
intermediate ring
pulley and Woodruff key
lock washer
armature nut

I reckon the "inner splash ring" was helpfully thrown away by the last person who "reconditioned" your generator.

Rob

Thanks Rob

As I suspected. Time to find a "donor" generator to build one from two.

Cheers

[Jolls]

I dug around in the "washer bucket" this morning and found a shim of the right size so put her back together temporarily an have her running as a motor. I will look at getting a sealed bearing to replace the one in her at the moment and give her a lick of paint. That should be all I need to do in the short term; however, will need to be on the lookout for some brushes down the track.

[Harv]

A little late, but here is the diagram from the FE/FC manual:

https://imgur.com/a/nc47Lio

Cheers,
Harv

[Jolls]

A little late, but here is the diagram from the FE/FC manual:

https://imgur.com/a/nc47Lio

Cheers,
Harv

Thanks Harv,
That is gold. So I was only missing the wavy washer and the felt. I turfed item 28, the retainer cup for the felt seal and put in a shim. I don't think I need it because from that diagram the pulley wheel sits on the shoulder of the armature with no other support. So I will get into town and purchase a sealed bearing and be on my merry way!
Cheers n Beers
Craig

[Jolls]

To save me pulling the genrator back down (no troubles at all to do if I have to) does anyone have listed in their bag of tricks the bearing size/part number for the Basch Generator? I'm creating a spreadsheet to track this stuff for when I need it down the track.

Cheers n Beers
Jolls

[my8thholden]

Hi Jolls  .I rebuilt my Bosch generator myself , I have the bearing part number somewhere , it wasn;t were I thought it would be ..quite straight forward really  ...I removed the paper from the field coils and wrapped in fabric tape , not too much there is minimal clearance and then coated that with varnish ..I have a few sets of various brush sets , I found some I could grind down to size on a green stone and have been working for few years now ..Vern .

[ardiesse]

Craig,

6203LL for Bosch, 6202LL for Lucas.

Rob

[Jolls]

Hi Jolls  .I rebuilt my Bosch generator myself , I have the bearing part number somewhere , it wasn;t were I thought it would be ..quite straight forward really  ...I removed the paper from the field coils and wrapped in fabric tape , not too much there is minimal clearance and then coated that with varnish ..I have a few sets of various brush sets , I found some I could grind down to size on a green stone and have been working for few years now ..Vern .

Hi Vern,
I patched up the field coils with liquid electrical tape as most of the paper was in pretty good shape. Cleaned out the ouled up gink in the plain bearing and re-oiled it. All I need now is a sealed bearing - she is running great as a motor so I expect no problems in the short term. I have purchased a Lucas as a spare and will chase down a Lucas regulator to go with it just in case. I also purchased a spare starter motor as well so I can have a rebuilt spares sitting onthe shelf for when the day comes!
Cheers n Beers
Jolls

[Jolls]

Craig,

6203LL for Bosch, 6202LL for Lucas.

Rob

Thanks Rob, you are a Gem!

[Jolls]

G'day FC legends,

Firstly, I need to hang my head in shame for requesting the exploded view of the generator. It has been almost forever since I  owned my last FC, and almost as long since I was using the FE/FC shop manual. I had forgotten about the FC supplement in the back - low and behold I had the diagram all along. The one Rob so kindly posted is different to the one I have in the manual - but the one I have in the manual looks identical to what I have sitting on the bench so I am all good.

Secondly, Rob, thanks for the detail on the bearing - ordered it over the phone and it fit like a glove. What a great resource this site is!

So , the crunchy generator bearing has been replaced with a modern sealed bearing. I have it running fine, albeit with a 2mm washer as a shim to prevent the pulley dragging on the housing. With the 2mm washer in place I still have about 5mm end float. This is because a previous "mechanic" has turfed the inner bearing splash (spacer). This is part number 46 in the exploded diagram of the manual. 

This is where the wisom of the forum comes in again - what is the depth of the missing component? I need this info to correctly align the generator with the drive belt. I'm sure I can guestimate but if anyone knows the depth or has a spare one they could measure for me I would love to hear from you. Once I have the specs I can turn one down, paint the genny, and tick it off the completed list.

As an aside - does anyone have a list of the Bosch codes so I can decipher the stamping? I have found a list of date codes from 1960 on available on the net but nothing useful in my searches so far.

Thanks in advance for your advice.

Cheers n Beers
Jolls

[Harv]

Firstly, I need to hang my head in shame for requesting the exploded view of the generator. It has been almost forever since I  owned my last FC, and almost as long since I was using the FE/FC shop manual. I had forgotten about the FC supplement in the back - low and behold I had the diagram all along. The one Rob so kindly posted is different to the one I have in the manual - but the one I have in the manual looks identical to what I have sitting on the bench so I am all good.

My bad... I think I posted the Lucas diagram from the FE manual, rather than the FC supplement.

Cheers,
Harv

[Jolls]

My bad... I think I posted the Lucas diagram from the FE manual, rather than the FC supplement.

Cheers,
Harv

Not an issue; thanks for the effort!

[ardiesse]

Craig,

I've got a Bosch generator which spat the armature windings on the way out Harv's one fine afternoon.  It's basically only good for mechanical parts, and brushes.

Rob

[Jolls]

Craig,

I've got a Bosch generator which spat the armature windings on the way out Harv's one fine afternoon.  It's basically only good for mechanical parts, and brushes.

Rob

Hi Rob,

If you don't need the internal spacer, or if you want to get rid of the whole think for parts, let me know the damage. I am an electrical fitter mechanic by base trade; haven't touched rewinding an armature since I was at tech. Could be a project for retirement - just got to recall how to do it without all the smart machinery they have today. Windings by hand could be tedious - unless I could find an old winding machine somewhere - I already have the lathe etc.

As an aside I have read the threads on here and the FB/EK forum regarding your generator test set up. I have been contemplating something similar for a while. I have my eye on an old US WW2 LV test kit on eBay; postage is a killer but would be a great setup for testing generators/regulators on the bench and in the vehicle. Just working out if I can get it shipped cheaper using a third party service so I only pay internal postage to the US seller. Otherwise it may be time to make something similar to your setup. Have you modified it any further from the way you had it set up at the end of the threads?

Cheers n Beers
Craig

[ardiesse]

Craig,

The generator test setup's three phase motor could do with more oomph, but you make do with what you can scrounge from work . . .

The other problem's got to do with switching transients in the dummy load.  I'm using low-dropout voltage regulators with booster transistors as constant-current loads.  All fine in theory, but the practice is a different matter.  The regulators can turn off way faster than the generator can react.  I had an FJ Bosch generator on full song, and turned the 20A load off.  There was a coughing sound, and the magic smoke came out.  The field current had to decay somehow, and it did so by generating a huge voltage spike, which took out the lower-current sections of the dummy load, and the cooling fan.

I've thought up a soft-start and -stop system, but it'll use a voltage reference and op-amp instead.  Still to be implemented.

And don't admit that you've had experience at rewinding DC machine armatures.  I have a couple of 6V Delco generators needing armature rewinds . . .

Rob

[Jolls]

Craig,

The generator test setup's three phase motor could do with more oomph, but you make do with what you can scrounge from work . . .

The other problem's got to do with switching transients in the dummy load.  I'm using low-dropout voltage regulators with booster transistors as constant-current loads.  All fine in theory, but the practice is a different matter.  The regulators can turn off way faster than the generator can react.  I had an FJ Bosch generator on full song, and turned the 20A load off.  There was a coughing sound, and the magic smoke came out.  The field current had to decay somehow, and it did so by generating a huge voltage spike, which took out the lower-current sections of the dummy load, and the cooling fan.

I've thought up a soft-start and -stop system, but it'll use a voltage reference and op-amp instead.  Still to be implemented.

And don't admit that you've had experience at rewinding DC machine armatures.  I have a couple of 6V Delco generators needing armature rewinds . . .

Rob

Thanks Rob

It would be great to get hold of an original GMH test set and see the internals - they obviously solved the problem and I expect the answer is something pretty low tech. Large ceramic wound variable potentiometer perhaps.

As for the armature rewinding - only ever done it at Tech as it was part of the trade back then. Once I was in the field motors were checked and if the fault was in the windings off it went into a dedicated shop. Most of the practical aspects we covered really demonstrated the theory. I had to repair an armature once to demonstrate I knew how and ticked the box. Since then I have only dabbled in the fitting side of things. Rewinding isn't difficult if you have the tools, doing it by winding them buy had would be a labour of love!

Let me look into it - if it is not too much to get set up you may get your generator armatures fixed! It may cost you a Bosch spacer! Haha

Cheers Jolls