Cummings 10 amp circuit breaker tripping with new alternator

220 hp Cummings 2004 boat, put 210 amp Idlepro Leece Neville alternator wired neg and pos directly to house bank. Keeps tripping engine breaker. Leaving Friday for Bahamas, really would like to fix! I did change out breaker, still trips. Any ideas?

I don't think I have enough information to hazard a guess. I don't know, for example, the size of the breaker or where it is in the circuit relative to the alternator and which engine load it is associated with, e.g. ignition, starter, charging, etc.

So, a few questions:

-- When does it trip the breaker? When connected or once the engine is started?
-- What size is the breaker?
-- Where is the breaker in the circuit? Any chance you can hand sketch the circuit showing alternator, battery, and engine wiring as well as breaker and upload a photo?
-- Was the alternator every wired reverse polarity? Even for a moment? If so, is the diode good?
-- What gauge is the associated wiring? What is the longest length?
-- Are you using the remote sense capability? If so, how is it wired?
-- Is it internally or externally regulated?
-- Does it work if you put the old one back?

Cheers!
-Greg

Which engine breaker? That is a big alternator. If it is the "ignition" breaker that supplies power to the alternator's field then the new alternator is requiring too much current and is tripping it.



Get a clamp on DC ammeter and measure the current in that circuit. You might need to rewire that circuit with bigger wire, probably 12 gauge and upsize the breaker to 15 amps.


David

djmarchand said:

Which engine breaker? That is a big alternator. If it is the "ignition" breaker that supplies power to the alternator's field then the new alternator is requiring too much current and is tripping it.



Get a clamp on DC ammeter and measure the current in that circuit. You might need to rewire that circuit with bigger wire, probably 12 gauge and upsize the breaker to 15 amps.


David

Click to expand...

Agreed. Might also consider an external smart regulator and dedicated wiring for the big alternator which would let you leave the OEM wiring and breaker alone. With the external regulator, you can detect the charging voltage and temperature right at the batteries which would allow for better control, faster/more complete charging, greater battery capacity, and longer battery life.

CB operate at different loads and speeds.

Perhaps the CB you have is too sensitive .

A simple cheap test would be a slow blow fuse to see if that's the hassle.

Trips in 15 secs, does not trip if + is disconnected. + and - connected directly to battery.
10 amp push button breaker , on engine, just like the Genset.
New alt,but had on another boat short time , worked fine.
Remote not hooked up.
Internal, Neg isolated, must have Ground wire.
Doesn't trip when positive is removed before starting.
Doesn't have ign wire, self excited.
Planning on possibly using Balmar external after this trip. Out put should be 14.0
Have solar for trickle
DC clamp meter of wire going to breaker ~12-15 amps. wire ~12guage and I assume it operator the engine sensors

Cummings 5.9 bt M 220hp 2004

I have different boat now

I have a 2004 Heritage East now, need to change Avatar, but I still have the Gulfstar, will sell when I get back.

Ok, so this engine breaker does not supply the alternator. So what does it supply that draws 12-15 amps?


David

10 amp breaker with 12-15 amps going to it?

Mechanical engine. Do U have the air heat option or the preheat option? Is the fuel cutoff sol. very warm?

NOte that having the alt running will increase the DC voltage a few, and if this bad load is marginally too high, then the alt voltage might put it over the edge and trip the CB.

Move the negative from the alternator back to the engine and see what happens.

Just had a thought. The Cummins has an energize to run fuel solenoid. Since it is on all of the time it has two coils: a pull in coil that draws more current and a hold coil that draws less. If the internal contacts are bad the pull in coil may be energized all of the time resulting in more than normal current draw.

Use your clamp on ammeter to check the current drawn by the coil when the engine is running. If it is the 12-15 amps then replace the solenoid. The coil will eventually burn out anyway and leave you with a dead engine.


But after thinking about it some more the engine would immediately die when the breaker trips, so my theory above is probably all wet.


David

Two schematics are below courtesy of Tony Athens several years ago.

THe C.B., the only one that appears here, appears to get its power from the starter solenoid. It is 10A. Trace it through and it appears to go to the terminal block C1 - 4 and then to the Gear oil pressure sensor. While installing the alternator is there any chance you monkeyed the wiring causing a short cct.

Maybe I am misreading this but take a look.

Which specifically is your engine?
Which alternator specifically did you remove?

lost mssg

I tried to post a reply, a very long one for me, of what happened today.lost it all. I will try tomorrow, I am leaving for Key Largo in morning. Thanks to every body.

The engines are Cummins 6bt5.9m. Today I replaced the 10amp breaker with a 20amp fuse on the port engine (by generator being installed on port engine). The fuse had fairly small gauge wire maybe 16 or smaller. I started up the engine and observed all wires for temperature and found the small gauge wire getting warm. The engine kept running making a modest amount of amperage because batteries were fully charged. I am thinking of replacing the fuse block with a heavier gauge. Then I smelled the dreaded burnt wire smell and then screamed to my wife “kill it Kill it” she replied it wont stop. I grabbed the pliers to pull the fuse and it broke I pulled out the pieces and the motor kept running. I came up to the helm everything is dead. I go back to engine room and there is no manual shut off like the “Perkins” I look at the starboard engine looking for an emergency shutoff so I shut off all the fuel and it eventually the port engine stopped. At this point, I felt defeated. I am trying to put this together for two hours with 16hours to go…scrap!!!! Scrap!!! scarp!!!!!!!!!!!!!!!!!!!!!! I put the old breaker back on, disconnected the alternator from the battery, bled the fuel on the engine and by God the darn engine started. We are leaving in the morning. We will be gone three months, I will study the wiring diagram and try to get this 210amp dc (Generator) back online. We are leaving Marathon and going to Key Largo tomorrow and God willing the next day to Bimini. The only reason this is getting posted is because my lovely wife is typing this. Trawler Forum people are the best community. Thanks....

bring an epirb

Sounds like an exciter lead that should have a resistor or light bulb, but once hard wired exciter current back feeds into the ign circuit and that is what prevented a shutdown.

How many leads total come off the new alt?

Saga

I am collecting my thoughts since a lot has happen since my 1st post. I left Marathon on the 1st, Crossed over to Bimini the next day, my very 1st crossing plus solo, had good weather..Moved fast because of weather and made it to Rose Island on the 5th. I disconnected my positive cable to the Alternator before make the trip, started to take off belt since it only turns the Alt. The water pump is geared. Then put belt on because the Tach runs off the “W needed, only “W” lead for tach. Yes, I and it did work!! with no other connection, so I had a tach for the trip, damn important. Next will call tech Monday and go over over fuse problem, No exciter wire I did rewire into one main 1250 ah bank before I left and add a Victron battery monitor. It WiFi to your phone, So great and easy to ck usage. Surprising with the rewire, the solar pick up the daily usage approx. 300-400AH. In 8 days I have run gen set 2x for 3-4 hours total, very happy. Have a ice maker, 5cuft freezer and 10 cuft freezer. Wish I could get the alternator working as a back up.
Still open to ideas what to check., Waiting out winds the last few days , then moving the the Exhumes I brought an ACR EPRIB. And an Islander WiFI system.

You are officially in paradise.

You may have to get right down there , if not done already, and TRACE the wiring that the 10A breaker is attached to so you know where it is attached, both ends.

We are all guessing and so far the guessing has missed.

You never did answer my question about the engine and the alternator specifics. Also which alternator was on the engine that was replaced?
It may not help but it may and without information all of us are hampered.

Update

I will trace out every cable soon. Engines are 220HP Cummings 5.9 , Alternators stock Delco Remy, I don't have info but I think they are approx 85 amps. Up grade to Prestolite Leece-Nelville Idle Pro AVI 160-2008 210amps Continuous Duty. It is made for school buses, etc. make 170Amps at Idle all day long, 14.0 volts

"Up grade to Prestolite Leece-Nelville Idle Pro AVI 160-2008 210amps Continuous Duty. It is made for school buses, etc. make 170Amps at Idle all day long, 14.0 volts"


A smart 3 or 4 stage V regulator with a batt temp sensor would be a great addition.

FF said:

"Up grade to Prestolite Leece-Nelville Idle Pro AVI 160-2008 210amps Continuous Duty. It is made for school buses, etc. make 170Amps at Idle all day long, 14.0 volts"


A smart 3 or 4 stage V regulator with a batt temp sensor would be a great addition.

Click to expand...

AND an alternator temp sensor.

I looked up the Delco alternator. You likely had a 15SI which was 85A. THere are others close but they produce either more or less current. These alternators were used on the 6bts.

Will go back and study the schematics and hopefully I can see something

Don't run without the belt!! A Cummins B220 one of the pulleys is the coolant circ pump. Yep, sea water pump is gear driven, but not the coolant pump.

Ski in NC said:

Don't run without the belt!! A Cummins B220 one of the pulleys is the coolant circ pump. Yep, sea water pump is gear driven, but not the coolant pump.

Click to expand...

I knew there was something else that the belt did!!!!

original cummins installation the alternator plugs in. sounds like you have replaced the plug (and maybe some of the original loom) with direct wiring.
in itself that is a good thing to do, but it is possible you have "lost" the diode contained in the engine wiring loom in this process.
this diode is within the wire which provides power from the key switch to excite the alternator on startup. after that it is self excited (unless you have an external exciter which i think you have said you do not)
if diode is missing it is possible you are now backfeeding from the alternator to the output side of the key switch when the engine is running thus effectively bypassing the key switch , that i believe is the reason for engine not stopping when you turned off the key switch.

your 10A breaker is tripping because it is carrying more than 10A, by your own readings, it is supposed to do that ??? if the diode is missing then key switch feed is still connected to the exciter circuit when the engine is running, this could be the reason for your excess amps.

Loom had 3 wires, only 2 were used originally, I reduced to 1. The “W” wire feeds the tach, unit is self exciting, no other wires needed. Hook up for sensor “S”. Haven't seen a diode nor removed one. When the engine didn't stop, I think is a big clue.
I haven't worked on Alternator set up, I have been Macgyvering a lot. Had a Xantrex inverter fail, have to keep the frozen food cold. I brought a spare inverter charger. Not much here it is really remote. Solar has helped alot. I will reread all the info you guys send me and tackle this problem.