50 dn generator

[chessie4905]

I'm going to reinstall a 50dn alternator that was removed before I purchased conversion. Gear train is fine, just plated over. Wires are there, just taped off. Anyway, I have two 50dn's, One a takeoff from my parts coach and one I purchased from Nimco a few years back. The Nimco one has the oil line upgrade one it but fewer teeth on the drive. Bearings are quiet when you hand spin it. No tag on it and painted gray.Can I just install proper gear and use it? Anything I not realizing?
I'm going to install new drive and driven gear and do the adapter centering procedure in the manual with dial indicator.
I know some (Cliff) don't care much for the gear driven ones due to cost of catastropic failure, but otherwise, any other thoughts?

[luvrbus]

One is for the Sun gear drum drive setup (planetary)  the other is for a direct drive

[TomC]

Better to convert the rear drive to a double V-belt and then run a couple of 160amp alternators from trucks ($160ea), cheaper and if one locks up will only take out the V belt, not the drive train ($$$$). Good Luck, TomC

[Bill Gerrie]

I have used the direct drive off the engine 50DN for over 30 years on various engines and never had an issue. Be careful when you install the 50 DN to the engine as there are several gear combinations and they are not interchangeable. You must have the proper one or you will bust the housing.

[luvrbus]

I have used the direct drive off the engine 50DN for over 30 years on various engines and never had an issue. Be careful when you install the 50 DN to the engine as there are several gear combinations and they are not interchangeable. You must have the proper one or you will bust the housing.

You have been real lucky Bill Gerrie,ask LVMCI what can happens he is the most recent causality I know, it cost him a 8v92TA last year   

[Utahclaimjumper]

 People also think they can just bolt it on with out setting it up with prussion blue to establish the fit,,a real no-no.>>>Dan

[Bill Gerrie]

I've heard that but I guess till I have trouble I won't know for sure. I sure hope it doesn't happen to me.

[luvrbus]

I've heard that but I guess till I have trouble I won't know for sure. I sure hope it doesn't happen to me.

I hope it never happens to you either it is sad seeing grown men cry 

[chessie4905]

I know there are specific gear combos for the 4905, at least and will use the ones that are of the parts coach which match the tooth count specified in the parts book. I was wondering if the gear drive 50 Dn's are all the same otherwise, and we're run faster or slower in city bus use with different engine....8-71, 6-71, 6-92. I do know they make a belt driven 450 amp 50dn plus. Just didn't know if the one I have is same output as in the 4905. I will use the dial indicator on the drive gear to pilot hole in adapter and adjust as necessary to obtain .002 or less run-out as specified in manual.

[luvrbus]

If you are going to use the 50D ,I'll check my boxes in the next few days I have the Kent/Moore J-29883 fixture to set those up if it hasn't grew legs and walked off

[chessie4905]

Thanks.

[chessie4905]

Found this info on improvements over the years.

http://busfixx.tripod.com/busservice/id23.html

[TomC]

When my 50DN gave out, it stopped charging-but was still turning. Since it was overheating, I disconnected the big battery cable till I was able to replace it. Being a V-drive, the alternator was easy to get to through the side engine access door, but with it in about 2ft, I made a ramp out of 2-2x4's (weighs 100lbs!). I took it in and they gave me a rebuilt exchange with all upgrades already done. With also changing the big transistorized voltage regulator to a digital voltage regulator (about the size of a pack of cigs), it cost right at $1,500. When I mounted it back in (major grunt to get it back in position-even with the 2x4 ramps), I estimated the clearance and bolted it down. Still working many years later-guess I lucked out.
Only thing, even with the digital voltage regulator, my voltage surges up and down-hence you can see the headlights getting brighter and dimmer quickly with the voltage regulator kicking in and out. I also run with the headlights on at all times to give the alternator a load, otherwise the alternator charging light comes on. Good Luck, TomC

[luvrbus]

Funny thing about the 50D gear driven a bus engine is the only place you will find one,not saying truckers are smarter than bus people  but replacing the belts is a  easier job   

[chessie4905]

The average truck doesn't need a 270 amp alternator either. Although I've seen a few that may need 1000 amps with all the lights some add.☺