• If you like antique engines, vintage tractors or old iron, please register and join us. When registering, please provide your CITY and STATE as your location!

26Kw Alternator and 4-53 Detroit Diesel?

wbartlett1

Registered
I have 26KW PTO generator that I want convert to a GENSET. It has a bell housing with a normal SAE pattern to mate to ( I am hoping) a 4-53 Detroit Diesel (non-turbo) producing approx 170 hp at 1800rpms. Is this too much engine, will it hurt the alternator? I may draw 10-12KW max in an emergency situation if my neighbours don't also plug in.

Wayne B
 

Birken Vogt

Email NOT Working
See my other post but it won't hurt the generator unless you overload the generator, then it will put the hurt on it good because it will happily drive the copper into smoking territory.

I'd like to know more details about the proposed project.
 

wbartlett1

Registered
See my other post but it won't hurt the generator unless you overload the generator, then it will put the hurt on it good because it will happily drive the copper into smoking territory.

I'd like to know more details about the proposed project.
Thank you for your information. I live in an area prone to extended power outages and wanted a backup generator to power the house and garage. I know this setup is overkill but that's what I have without going out to buy something else. The alternator is 'Aircraft Appliance and Equipment' brand and the Detroit Diesel 4-53 was formerly a backup fire pump at an airport. Both work beautifully now but have never been mated.
 

Triple Jim

Registered
I suppose you could rig up a device that sensed output current and kills the engine if the alternator is overloaded for some set length of time.
 

25Eagle34

Registered
As long as your 25KW alternator has the correct size circuit breakers, your alternator is protected no matter what size engine you have powering it. Anyway, I doubt you would ever use the 25KW for the loads you discussed unless you are trying to Power all of the neighbors. What kind of panel and breakers does your alternator have?
Good luck and have fun with your project!
Don in California
 

Birken Vogt

Email NOT Working
Normal circuit breakers don't really protect the generator unless they are undersized or super-special. Nowadays we use current sensing controllers instead which will shut down the engine if you exceed whatever you have programmed for a programmable length of time.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
A 26 kw alternator?!? Is it 12 or 24 volt?? That would be like 1,000 or 2,000 amps!!! :eek: :O
 

pegasuspinto

Registered
The thing on the back of our 'generators' is an alternator, making AC

I AM assuming that he has looked at the data tag, and it's a 120/240 60 cycle unit.

He should also look into the gen end and make sure it's a 4 pole 1800 RPM unit, I am assuming he's removing a gearbox and I guess it COULD be a 2 pole 3600 RPM unit, if so he's pretty much screwed on this project. If he's really really lucky it's a 6 pole 1200 RPM unit.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Don't think he'll be lucky enough to find a six pole PTO generator (does such an animal exist?), but you're right, he may well have a two pole generator.

*Alternator* would not be incorrect, just sounds funny. But ALL machines that convert rotary power into electrical power are generators, even the rectified AC ones in automobiles. :brows:
 

cornbinder89

Registered
I've also heard it this way: If the output is A/C it is an alternator, if D/C it is a generator, so even the little beasty's in your car are generators.
Kinda hard to make a hard a fast rule, as even generators produce A/C in the armature and it is mechanically turned to D/C in the commutator.
Both terms get thrown about with equal abandon.
 

bunkclimber

Registered
the 4-53 has more than enough power to spin your alternator under load and then some.That engine really starts to level out about 2000rpm and up,with an 1800rpm (4-pole)it would do OK.If you can turbo it it'l perform better but I think the turbo would have to be sized for mid-range rpm and not top end.One thing you'll have to change is the governor on the engine if it came from a vehicle..you need a droop governor or better yet,electronic governor actuating the fuel rack on the engine.The vehicle engine typically has a limiting speed governor,wrong type for a genset.If you go electronic governor you can bypass the present governor..a bit scary as I like some kind of limiter or shutdown.The newer digital governors you can program for overspeed.FWIW
 

Birken Vogt

Email NOT Working
The 4-53 has some kind of governor on it but it might be set at 2800 or something you would not want to go with an 1800 RPM alternator. You might be able to just dial it back to something more reasonable like 2000 and then let the electronic governor take over from there but you would have to be sure the mechanical governor was not also interfering. Knowing how Detroits act I bet this plan would work but ymmv....
 

Charley K

Subscriber
Last Subscription Date
10/09/2019
Hi, My generator combo is a Mercedes 240d 4cylinder @70 hp on a 25kw Generac head running at 3600. The unit is sheaved at a ratio that works the engine at @ 2450rpms. This engine rpm limits the generator to 18kw.You could use belt and pulleys and pretty much tailor the rpms as needed. I used the electronic governor from the donor Generac to maintain the HZ. Works like a charm. You will need to figure the best rpm range to run the engine and ratio accordingly. At 170 hp I think you will have trouble with the engine wet stacking with light loads and a slow rpm out of the torque band. Good luck with your project, CK PS, I have a couple of posts on here of my build. There are a few pictures also. The guys on the forum were very helpful, some of the info may be useful to you. There was a post on here this morning showing an electronic governor on ebay, Would work well with your project.
 

Vanman

Subscriber
Last Subscription Date
07/10/2019
Detroits have such fantastic mechanical governors! I can't imagine introducing electronics to them.

They drive six pole or four pole generators, so 1200 or 1800 rpm. A 453 turning 1200 rpm ought to be plenty of power for a 26 kw generator.

If the PTO generator had a 1000 rpm input, that'd likely work quite nicely as well.
 

Birken Vogt

Email NOT Working
I did not read back in the thread but since this engine was a fire pump your are right, it likely does have a good constant speed governor. If it has enough range to get down to 1800 RPM. Or maybe it is already set there, who knows what the fire pump ran at. Inquiring minds want to know.
 

Charley K

Subscriber
Last Subscription Date
10/09/2019
If the generator is two pole, direct couple will put the engine out of the rpm range. 1200 rpm will also put the engine out of rpm range. 1800 rpm head would work but would be very lightly loaded and wet stack. The engine is to large for the project. Two stroke diesels don't fair well with light loads, fuel consumption will be high. Look around the internet, there is a lot of information regarding the governor. There is much well intentioned advice on forums. Do your research before spending your money. CK
 

Birken Vogt

Email NOT Working
71 series were run at 1200 RPM with smaller 6 pole generator heads. 12-15 kW if I recall correctly. I don't think there is any reason you could not do it with a 53 series. There might be minor issues with engineering items like cam timing, compression ratio, blower size, etc. but for hobbyist use it is probably just a small loss of efficiency. If you can get the governor to go that low without changing springs or something.

As always, beware of uncontrolled engine speed when messing with a Detroit governor.
 
Top