D2 Generator to alt conversion

[Old Magnet]

You can have a go at the ridged shaft if you like but bare in mind there is a reason for both quality conversions on the market having flex couplings. The test will be bearing and/or shaft life.

As far as dust control for the 10SI there are two options for mounting screens on the back of the alternator. One is the marine application which uses a combined flame arrester/screen consisting of three layers of fine mesh built in to a cover housing. The other is referred to as a "chaff" screen which is similar to the marine unit but one layer of screening and a lighter cover housing.

Bearings in the 10SI are the needle bearing prelubed type on the back end and prelubed enclosed ball bearing on the front.......adequate but not what I would call beefy.

Got the "Supper" call, will add more later

[ccjersey]

I would simply remove the bearing next to the fan on the alternator. It's pretty simple to get into one of these and reassemble when you are through. That would eliminate the stress on the shaft and only require a longer spacer between your female threaded shaft extension and the shoulder on the rotor shaft. Any misalignment (inherent in a welded assembly) will result in a cracked housing or cracked hollow shaft extension at the point where the threads end and the solid portion of the shaft begins. I don't believe the bearing will be able to self-align and relieve the stress on the shaft. The most likely misalignment (radial?) will cause a bending of the shaft with every rotation.

Do be aware that some of these alternators have varying lengths of shaft where the pulley mounts which could require modification of the spacers/shaft extension length.

It would be a special order, but the 10SI can be had without many of the normal perforations on the rear of the housing (opposite the drive end). I used to have one that was retrofitted onto a machine by our local gen/starter shop, way back when. I haven't seen any lately like that. The tendency is to demand more and more amps these days with some of these alternators rated @ 90 amps, so for these, cooling is very important. Just keeping the battery charged on a dozer would not likely require very much in the way of cooling.

The delcos don't last forever under agricultural use, but are readily available and easily repairable. In addition, there are several competetive makes that will bolt into the same dimension mounts and use the same connectors.

[Old Magnet]

ccjersey hits on where I was going with my previous post but I had a heck of a time finding the pictures I wanted showing the option.....had filed it in my "junk" file

This approach could satisfy the "gypo" requirements as a cheap solution. This is a current commercial available unit that is a prime example of how not to do it.....free hand torch cut flange, no slotted holes for adjustment and convenient mounting bolt indexing that interferes with lugs on the alternator casting. Does not have a cooling fan.......but does not require a coupling.
Also seems to be a problem of enough space for the mounting bolt wrench access on some of the housings.

But......all is not lost.....if done properly it could be a satisfactory application.
If used at a low amperage (battery charging) mode the amount of heat generated may not be that severe. Also as a one wire set up using the low voltage cut in that eliminates the tri-diode set up you only have to deal with the voltage regulation electronics.

[jmvmopar]

Old magnet. That could be a good idea, just use a ND alt like on a chrysler product where the fan is internal to the alt.

[OzDozer]

G'Day all! - Well just a little update here .. OzD has been hard at work, figgerin' the ultimate design for an alternator drive adaptor for the old Cats .. and my machinist buddy and I, have finally produced the working prototype ..

Voila! .. the piece-de-resistance!! ..

A.

The design of this adaptor has taken us a few weeks of brain racking .. design .. redesign .. rethink .. redo .. and generally running into blind alleys .. until we came up with a design that was as simple and robust as we could get .. without involving vast amounts of components, and work.

After discussions in previous posts, with Old Magnet and ccjersey .. who both inputted excellent advice .. we finally settled on the following ..

1. The adaptor is steel, and comprises machined and welded components ..

2. The design involves a short shaft, carried on two standard 6207 ball bearings .. separated by a spacer, and retained by a circlip .. this shaft is located in a machined, heavy-wall-tube housing .. which is welded into the mounting flange plate ..

3. The original generator drive gear is used, without modification. The original gear is unbolted from the genny, and slipped on the keyed shaft, and retained by the same nut and woodruff key as original ..

4. The mounting flange plate is slotted for drive gear depth adjustment, as recommended by Old Magnet ..

5. The design has a Lovejoy coupler, bolted to the short shaft, as the connection between the adaptor drive shaft and the alternator ..

6. The alternator used, is a standard Delco 10SI, of the voltage, and number of wire connections, of your choice.
There are NO alternator housing modifications, or specially machined faces, or any fancy parts required, to bolt up a bog-standard Delco 10SI.
This allows 5-10 minute changeover of any faulty alternator, and the end user can acquire and utilise a new or used Delco of his choice, and in his price range.
You can run down the street, and pick up a $20 alternator from a wrecked Chevy, and use that, if you wish.

7. The alternator half of the Lovejoy coupler is machined to fit the standard 10SI shaft. The nut is unscrewed, the pulley removed .. and the Lovejoy coupler spider is slipped on and retained by the same nut as original .. the alternator fan stays in position, and is retained on the alternator shaft, precisely the same as original ..

8. The alternator is retained by using a specially-machined stud that fits the lower housing mount hole in the standard 10SI .. with a nut and washer added .. and the top of the alternator is retained by utilising a bolt screwed into the top adjuster lug.
This effectively means that the alternator is retained in precisely the same manner as when fitted to any auto engine ..

To install the alternator, the Lovejoy spider is bolted to the alternator .. the alternator is lifted into alignment with the specially-machined stud .. then slid on .. with just a wriggle to align the Lovejoy coupler spiders .. then the nut and washer screwed on the stud and tightened .. and then the top bolt is screwed into the adjuster lug and tightened ..

Unfortunately, the cost of manufacturing the adaptor, is not as low as I would have liked .. and I don't think we can compete with any commercial adaptor produced in the U.S. This adaptor has ended up weighing around 10 lbs (4.5 kgs) and freight is a killer for any distance nowadays.

We are looking at AU$400 (US$300) for one adaptor, complete with new hardware and installation instructions. Freight anywhere in Australia will be AU$20 .. but freight costs to the US are in the order of AU$100 (US$80).
Hopefully, we will be able to supply enough of these adaptors to Aussie customers, to turn a small profit ..

The adaptor pictured in this set, is our prototype. There will be minor design modifications to the final product. We erred with some length measurements on the prototype, because we never had the RD-4 engine handy to recheck our distances.
The rear mounting plate will end up a lot closer to the alternator fan, in the final design .. with the 80mm tubing that covers the Lovejoy coupler being lengthened by about 3/8" (10mm) .. and spacers between alternator and adaptor being about 3/8" (10mm) shorter, accordingly ..

At present, we are only producing an adaptor for the D4400 engine. If someone wants one for a D3400, we will need accurate diagrams, or a D2 generator, to calculate the modifications required for any other drive gear size (the RD-4 gear is 26 teeth) ..

Here is a heap of pics showing the alternator coupled and de-coupled, and fitted to the RD-4 engine ..

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[Old Magnet]

Hi Oz,
Looks good ...appears you have included all the design requirements. Basically the same as current US production units except your mounting accommodates the generic alternator without having to use the Delco/Motorolla conversion three bolt hole end housing. Might consider looking into an aluminum casting to help with the weight issue.

Have you done a run trial at speed yet?. Curious to see if the bolt/stud and coupling version will control vibration/alignment as well as the piloted housing mount versions.

[OzDozer]

OM - Thanks for the kudos. No, we haven't done a run at speed yet, but we don't see any major problems, as the operating RPM is low. We will look for an RD-4/D4 owner shortly, to test her out ..

The aluminum casting hasn't been seriously considered .. but now we have the final design, we could look into that. We were under the impression that a low production run of an aluminum casting wouldn't reduce costs by any serious amount .. and the weight saving would only be, maybe 2 or 3 lbs.

The Lovejoy coupler alone, still weighs around 2 lbs, even after machining .. and coupled with the need for the shaft and bearings, the only weight saving is in the housing .. making the total weight, still up around the 7 or 8 lbs mark.

[ccjersey]

I think it's a good looking design. I doubt it will have any significant vibration problem since it's driven by an axial connection instead of a belt and the spider of the coupling will damp some of the vibrations from being driven by a diesel engine.

You could go with crescent or triangle shaped pieces of steel for the stand-offs at bottom and top to spread the contact across more of the surface of the alternator if you think there might be a problem.

Well that won't work, looking at the picture, there is a raised boss around both the top and bottom bolt holes which would prevent any contact beyond your bushing anyway.

A stand-off made from plate would need to be countersunk to allow the surface of the alternator mounting ears to contact instead of just the boss around the hole if you wanted to get some additional stability.

[Old Magnet]

On these old engines....everything vibrates....and ya never know what's in tune with what to amplify movement. The two point mounting with limited contact area may not be sufficiently rigid in this application......as compared to the large three bolt mounting flange of the Motorola style adapter.

To cover the range of applications rpm's of up to about 2200 or so should be accommodated.

[ccjersey]

How about a brace from a convenient spot on the side of the engine over to the tapped hole in the back of the alternator. Perhaps with oblong holes in it to get it aligned correctly before it is tightened down.