955 circuit breaker poping

[fest777]

i have a 955 85j series that keeps poping the breaker, when i rev the machine the amp meter goes way up to almost 50 amps then it pops, its a rebuilt alt, what could be the problem a weak breaker, i thought the regulator was built in thanks anthony

 

[92U 3406]

You've got something drawing a lot of power. Look downstream of that circuit breaker for damaged wiring or damaged accessories.

 

[AllDodge]

its a rebuilt alt

Put a voltmeter on the bat or alt and see how high the voltage is going.

This wouldn't happen to be a 12V alt would it?

 

[mitch504]

I just came into this thread to see if you left out an "O", or a "P"

 

[fest777]

its 24v alt, when it revs the amp meter pegs to almost 50 amps then after 5 or 6 secs it pops

 

[fest777]

also the 12v question is a good one before it was a 12v alt and batt, it did the same thing popped when rpms went up, now it right with 24v system

 

[Welder Dave]

I just came into this thread to see if you left out an "O", or a "P"

Never heard of a 955 pooping but they could clean up a lot of poop.

 

[AllDodge]

also the 12v question is a good one before it was a 12v alt and batt, it did the same thing popped when rpms went up, now it right with 24v system

Never heard of a 955 with a 12V system
Need to measure the voltage. The alt may be going from 24 to 50V or other

 

[mitch504]

To do a given amount of work, a 12 volt system uses twice the amperage that 24 volts does, that's why cars went from 6 to 12v, and most heavy equipment is 24. Circuit breakers open when amperage gets too high, and some get weak when overloaded repeatedly. I wonder if running it on 12v did this to yours. 50 amps is not a huge breaker. I would find out what the ampacity is supposed to be, and check it with a reliable test meter, not a dash gauge.

 

[Klay]

Which breaker is popping and do you have a schematic diagram of the system or know what it is feeding?
I would try to isolate the circuit and trace the wire to the component that is drawing all the current after ensuring the CB is not weak by measuring the DC current through the CB with an amp clamp.

 

[DB2]

The older Cats had one main resettable breaker for the whole system. Just FYI.

 

[Nige]

The electrical schematic for this machine could probably be drawn on the back of a cigraette packet with space left over ... here is the offending article.

To echo AllDodge's comments I can't recall seeing this model with anything other than a 24v electrical system. Just a thought. Are the batteries connected correctly - in series as shown in the schematic below, and not in parallel..?

 

[fest777]

the batts are in series, when its was 12v it was a temp set up just for a week or so till the 24v system was reinstalled, there is no short anywhere, it just can not handle the amp spike thanks anthony

 

[petepilot]

the batts are in series, when its was 12v it was a temp set up just for a week or so till the 24v system was reinstalled, there is no short anywhere, it just can not handle the amp spike thanks anthony

the regulator either in the alt or if it has a remote it is letting the alt run wide open if not for the cb it would blow the batts up

 

[fest777]

that makes sense

 

[92U 3406]

Amps are inversely proportionate to resistance. A failed regulator will spike volts. The only way to flow more amps is if the resistance of the circuit(s) has dropped. You're looking for a short or short to ground.

 

[Nige]

the regulator either in the alt or if it has a remote it is letting the alt run wide open if not for the cb it would blow the batts up

The alternator would automatically want to run at maximum output if there was a short to ground. My 2c - YMMV.

 

[kshansen]

A couple questions on this wiring diagram. The disconnect shown just above and to the left of the starter appears to have the bottom two wires coming from the ammeter + terminal and then over to the out put of the alternator. Is this correct? I do seem to recall some machines where the output from alternator were maybe a pair of +12 wires, were they orange? not that the color really matters just what I recall.

The only other wires from the + side of ammeter are one to light switch and one to heat/start switch. Should be easy to isolate those two circuits.

I'm still wondering what was done to this machine when it was, for some unmentioned reason, hooked up as 12 volts. I could see in a very tight pinch installing a 12 alternator to act as an idle pulley for the fan but why would any wiring be changed for that just tape off the wires that would normally be hooked to the alternator. Now if the only way someone could get a machine like this running in a pinch you might need to install a 12 volt starter in that case I would just hook it up and let her rip. I've been running a Farmall BN for probably over 30 with a 6 volt starter running on 12 volts some day it might die but probably not before I do!

Have to believe there is much more to this story than we are being told, just saying!

 

[fest777]

i said it was a temp thing, why all the drama about a 12v starter and alt to move the loader when i first got it going, yes i ran it a short while like that didnt harm anything except no glow plugs, no harm no foul thanks

 

[AllDodge]

Could be your breaker is just weak. Mine will pop if I leave the glow plugs on for more then a minute. Mine doesn't pop just running but my gauge only moves up to maybe 30 after starting and then goes down near zero after running

My original breaker list as 3H4105 and has been replaced
If I just use serial number and breaker it comes back with 6T3645 which is a 60 amp and can find on ebay for $27