[encantotom]

hi all,

i have seen 3 of you now that have the alternator on your series 60 show low voltage.

on the last leg of my trip home a few weeks ago the voltage registering on the vmspc was 12.9-13.0 volts.

so, it is not where it should be.

but....my coach has the 300amp 50DN oil cooled alternator on it. it weighs a little over 100 pounds. and actually is a generator with a delco remy separate voltage regulator.

richard send me some documents on how to troubleshoot but i have not stepped through it yet. anyone have any experience with these big monster alternators?

thanks

tom

[RussWhite]

The autopsy on my alternator is complete. The pictures are on my daughter's camera right now. Root cause is looking like a loose nut that allowed the pulley to slip on the rotor shaft. That resulted in running way too slow and overheating. All the insulation is burned from the wires on the stator and many of the stator wires are melted and broken. I think he said my alternator had been modified and as modified had a 270 amp rating. I will have all diodes and bearings and regulator replaced as well as a new stator. Should be all done tomorrow evening or the following day - looking at a bill just south of $500. He will add a lock nut and we hope that will keep the pulley from ever slipping again.

[encantotom]

I assume yours is a standard style alternator from what you are describing.

Tom

[Richard]

Russ,

If you have the PennTex alternator, there is a key in the pulley that should have prevented the slippage.

[RussWhite]

Richard,

It is a Leece-Neville. It is now totally rebuilt and all new except for the housing and rotor. I will install it just as soon as it gets light. I will post some pictures soon.

[encantotom]

ok, cooled off some so went out to play with the newell.

the voltage is reading 12.8v. both on the vmspc and the gauge on the dash is close to that as well.

the voltage regulator has an adjustment screw on it. before i break something i need some info.

it shows a direction arrow to increase the voltage. but it has a allen screw cap there.

so, do i remove that allen screw to get at an ajustment screw or is that the adjustment screw? i didnt want to break it as the first impulse is just to start turning it. i tired a little and it was hard to turn.

anyone know

thanks

tom

   

[whatsnewell]

Have you put any penetrating oil on the screw to loosen it up? Looks to me like that is the adjustment screw, but God and elaine know I have been wrong before. In my more impatient days I would have just started turning the screw until it stripped out, or sheared off....

[Ozarkguy]

Tom that is the adjustment. Mark it before u move it then try to back it up a bit They do have resistantance when adjusting. But one wonders why the drop? Ground problems??

ok, cooled off some so went out to play with the newell.

the voltage is reading 12.8v. both on the vmspc and the gauge on the dash is close to that as well.

the voltage regulator has an adjustment screw on it. before i break something i need some info.

it shows a direction arrow to increase the voltage. but it has a allen screw cap there.

so, do i remove that allen screw to get at an ajustment screw or is that the adjustment screw? i didnt want to break it as the first impulse is just to start turning it. i tired a little and it was hard to turn.

anyone know

thanks

tom

[encantotom]

ok, i am thinking i am going to have to take this alternator off and go get it checked out.

has anyone taken one of these beasts off before? it is in a very awkward spot and weighs a little over a hundred pounds.

tom

[encantotom]

an update.

the hex screw in the voltage regulator is a plug to cover the hole. i took it out and the screw to adjust the voltage is inside and is a small flat screwdriver adjustment.

i used the vmspc as the voltage measurement.

when i started the voltage was 13.0v at low idle and 13.1v at high idle. sometimes previously it would dip down to 12.9v

to start with the screw slot was pointing at 1pm. 13.0v low idle 13.1v high idle

i adjusted the screw to 3pm (i was told it was sensitive) and now it was 13.4v both high and low idle

i adjusted the screw to 6pm and now it was 13.7v low idle and 13.8v high idle.

i talked to richard and he said that was right in the proper range.

so i put the hex screw cap back in and rechecked the voltage and it showed the same yet.

now my question is this. what does this mean? since i adjusted the voltage up almost a volt, does it mean that the brushes are 1/2 worn or something else is worn to some amount? any indication of if this adjustment shortens the life of the alternator in any way? or is it an indication of how long the alternator is going to last?

i am full of questions and looking for some guidance. i will try and call an truck alternator shop this week sometime.

any knowledge from you all?

tom