The 50D Alternator strikes again

[buswarrior]

This dark cloud has suddenly appeared over the gear drive 50dn.

There's 20 years worth of busnut internet history available for research, some here, most of it over on BNO, which historically involved way more industry knowledgeable people and engineers.

Nobody talked about this. Nobody.

Same old song, however. If you don't do your proper maintenance, if you don't install things according to the manuals, if you don't trust the former owner to have done any of the above...

Before the panic, can you wait for me to set-up a little business building over priced, ill fitting brackets to convert to pulley?

Happy coaching!
Buswarrior

[luvrbus]

They have always been a problem a bus engine is the only applications you will find one,they are a high amp, high rpm (3 x's the engine speed) and trying to cool with 200* plus engine oil is not a good recipe.The air cooled Niehooff 200 amp the military uses driven from the blower never gives a problem lol I do get my share of the 50D that went off, you may drive your bus for miles and never have a problem with the 50d but some are not that lucky like Mike,I never understood why people would want a alternator that takes 5 to 7 hp to operate.The 50D years back would break the cam Detroit had to start making a different cam just to drive the thing       

[Jim Blackwood]

That overpriced poorly fitting bracket does sound like a proper fix. If I had a 2 stroke you could sign me up!   

Jim

[windtrader]

I never understood why people would want a alternator that takes 5 to 7 hp to operate.

Are you saying a converted bus may not need so much power while running down the road? A smaller alternator would work to run headlights, running lights, charge the battery? There isn't much else pulling electrical power.
If that is the case and it is a real concern, then removing the gear driven 50DN and adding a 3rd party to run off the main crank pulley would be simple and pretty cheap, especially compared to the cost of fixing a blown up engine.

[richard5933]

Wouldn't the HP consumed by the 50DN be in direct relationship with the load on it? I understand that spinning an idle alternator takes some power, but certainly not 5-7 HP. I just ran some numbers through an online amps-to-hp converter and it came up with 7 HP to make approx. 270 amps @ 24v.

Whether someone 'needs' the 50DN really depends on a few things, like are they running the OTR heat or a/c. With the OTR a/c it's pretty much necessary to have that large of an alternator. You also have to ask what other demands are being placed on the system, like charging a large house battery bank, running a mini-split or large inverter, etc.

The other consideration is how much fab work someone is comfortable/capable of doing, since there really isn't a plug-n-play option for replacing the 50DN. Depending on how you mount the replacement, there will be need for new brackets, belts, etc. plus some wiring changes.

If I ever get a second bus and it's unknown how long since the 50DN has been serviced, it will be on my list of first-round items to be serviced/replaced.

[luvrbus]

Wouldn't the HP consumed by the 50DN be in direct relationship with the load on it? I understand that spinning an idle alternator takes some power, but certainly not 5-7 HP. I just ran some numbers through an online amps-to-hp converter and it came up with 7 HP to make approx. 270 amps @ 24v.

Whether someone 'needs' the 50DN really depends on a few things, like are they running the OTR heat or a/c. With the OTR a/c it's pretty much necessary to have that large of an alternator. You also have to ask what other demands are being placed on the system, like charging a large house battery bank, running a mini-split or large inverter, etc.

The other consideration is how much fab work someone is comfortable/capable of doing, since there really isn't a plug-n-play option for replacing the 50DN. Depending on how you mount the replacement, there will be need for new brackets, belts, etc. plus some wiring changes.

If I ever get a second bus and it's unknown how long since the 50DN has been serviced, it will be on my list of first-round items to be serviced/replaced.

The v drives in buses are the toughest to convert to a belt drive something is always in the way and are limited with out replacing the drive for the 50D ,Richard my Delco manual says the draw is 5 hp at idle your 7 hp at 270 amps at 24v is spot on with the manual for the oil cooled 50D,anybody with a belt drive 50D on a MCI can hear the engine change when a 50D kicks in at idle

[dtcerrato]

When we finally abandoned our air cooled 160A pos. grnd. generator. We revamped its carcass (housing) as an accessory drive for the new air cooled two belt drive 200A alternator. It has performed flawlessly for a few years now.

[niles500]

If you have an isolater charging 8 8d lifelines and otr ac a 50dn is pretty much a necessity- fwiw

[daddysgirl]

I certainly treat mine with like a baby, as I could not imagine having to remove the damn thing. It weighs more than I do.

[windtrader]

if you have most of the original equipment then you likely need the same power as the original so 7hp is 7hp. My point is with all that gone. no OTR AC, no seating with overhead lights, no 8D batteries. Really not much to power except headlights and charging the battery which are standard group 31 that charge up almost as fast as a regular car battery.

I don't plan on doing it but, it would be fairly simple to get a read of amps being pulled with the stuff on. With the OTR AC gone, there is a free spot on the pulley and the brackets could be easily adapted for a much smaller alternator.

I know them things weight a ton but it would be easiest to unbolt it and take a look at it's condition. oh yeah - just like the maintenance states. lol

[neoneddy]

I can say with certainty, the alternator does not use the same HP all the time. Go ahead and adjust the voltage and you'll hear the engine unload. Then on the other side when my Two ACs turn on and the inverters kicks in I can hear the engine load up some more.

I know it uses power, my best MPG was always spring trips when AC wasn't required.  I just don't buy it robbing 7HP just spinning the armature. 

Sometimes my solar takes over and I get the nogen light.

[luvrbus]

I can say with certainty, the alternator does not use the same HP all the time. Go ahead and adjust the voltage and you'll hear the engine unload. Then on the other side when my Two ACs turn on and the inverters kicks in I can hear the engine load up some more.

I know it uses power, my best MPG was always spring trips when AC wasn't required.  I just don't buy it robbing 7HP just spinning the armature. 

Sometimes my solar takes over and I get the nogen light.

Any gear driven assertories takes HP you guys would faint if knew how much HP a blower on the 2 strokes uses up 

[neoneddy]

Right, any friction / load of any kind takes HP. My point was the parasitic HP draw is not always 7 HP. I'd buy it being 7HP at the top  or middle ground, but if the batteries are full I'd suspect the load is closer to spinning the armature alone.

[chessie4905]

Set it up to not charge on grades to lessen draw when the hp is crucial.

[chessie4905]

Set it up to not charge on grades to lessen draw when the hp is crucial.