Just a word of warning
Old generators can be very dangerous, they can bite really bad.
If you are not really certain have someone who knows what they are doing check it out.
Old insulation failure and rodent damage are two culprits to watch for, and don't take for granted that the wiring has not been altered in some way.
cheers wimmera farmer

Deannis:

As other have stated the engine is D4400. Here is an explaination of the stampings:

110/220 For all Cat generators of your vintage there were two voltage options. The "low" voltage option was 110/220; the "high" voltage option was 220/440. The generators were all wired as 3 phase with nine leads and could be re-connected to produce single phase. In your case you could wire as 220V 3-phase or 110V 3-phase or 110V single phase 2-wire or 220V single phase 2-wire or 110/220V single phase 3-wire. When wired as single phase the power capacity is reduced by one-third.

37.5 KVA This is the maximum capacity of the generator based on heat rise. But for the D4400 engine at 1200 RPM the actual power output was 25 KVA 3-phase, equivalent to 20 KW @ 0.8 Power Factor. The sales model for the unit was "44-20", where "44" refered to D4400 engine and "20" refered to the 20 KW rating.

30KL1480 This is the serial number of the generator.

6B6428 This is a Cat number, possibly the generator arrangement number.

How many leads come out of the generator? Could be 9 lead reconnectable or maybe just a single phase 110/220 with 2 lines and a neutral. The voltage of a low voltage 3 phase set would normally be 110/190 up to 120/208 depending on the regulator setting.

There had to be some single phase generators put on CAT engines!

9 leads does not allow reconnection for single phase output by any commonly used connection. 9 leads only allows high voltage 3 phase to low voltage 3 phase reconnection.

12 leads out of the generator will usually allow a single phase reconnection by either the zig-zag or double delta connections. This does produce single phase voltages like 110/220 or 120/240 which we are used to in North America.

You can always get single phase power out of a 3 phase generator by connecting to only part of the 3 phase and the neutral if needed. For example, you can get 120/208 single phase out of a 3 phase generator by connecting to 2 lines and the neutral. It's unbalanced, but it will work and the generator will survive if you don't exceed the amperage rating on any line.

ccjersey:

Attached is the wiring diagram for getting single phase from the 9 lead 3-phase generator. As you can see one leg of the windings are not used and therefore the power output is reduced by one-third. To achieve 110/220 single phase, use T3 for LINE1, T8 for LINE2, and T2/T9 connected for NEUTRAL. Other connections can be used to achieve 110V single phase 2-wire and 220V single phase 2-wire.

QUOTE "it seems to be 110/220 which means in all probability that it is a single phase generator not a three phase which is what most generally shows up.. "

Disclaimer: I said seems, probability and generally..........

Everytime you think you MIGHT have it figured out, someone comes along and teaches you something new! Thanks KCB and ccjersey!

Jeff

That's a new one on me! Never seen it anywhere before. I am interested in the source of the diagram. Most manufacturers recommend either the double delta or zigzag connections for their 12 lead generator ends, but do not manufacture 9 lead ends any longer. After all, the difference in a 12 lead and a 9 lead is a few feet of lead wire to bring out the T10, T11, T12 ends of the coils instead of splicing them together as T0 in a 9 lead.

Looking at what it results in, it appears to be a version of a double delta. A double open delta.

Here is a repost of the complete generator connection diagram.
I'm no expert here but the 120 - 240v single phase option only seems to apply to units with the "Compensating Current Transformer Type" controls.

Here are some more pics. I have not checked leads yet more interested in getting running first, also been servicing d2 and going to work. The power plant has issues with pony motor, it will only roll over about 3/4 the way around then stops? Also its missing the mag. I am currently looking into direct electric start, or some other way to get it going. I am sure engine is good, it is not stuck and full of oil and anti freeze. Unfortunately the man who previously owned it passed away and nobody knows anything about it other than it was junk in their way. Thank god junk is cheap!

Looks like you have the direct start provision....I can see the bolt on cover plate in the pictures.

ccjersey - The wiring diagam I posted was from "Wiring, Lubrication & Maintenance of Caterpillar Diesel Electric Sets", Form 5682. No date given, but I suspect mid 1940's.

OM - I believe your reference is for later vintage generators with improved electrical controls. Your publication date is April 1958, about 15 years later than the D4400 unit.