Looking for some advice regarding a Cummins Genset

[Hanjun941]

Hi,

So I am currently troubleshooting a cummins generator that only seems to be able to switch from idle and rated speed mode during only after running for about ten minutes, any longer than that everytime i switch back to idle from running, there is no change and when i change it back to rated, the rated speed increases by about 100rpm, i remove the 24v battery and wait for awhile, when i restart the engine, all the settings are wack and I have to tune the governer settings back to normal i.e. idle and rated speed, however the same issue occurs, at the start i can switch modes fine, after awhile, the same problem occurs, I've connected the wires correctly according to Cummins manual and have replaced the governor controller and actuators, has anyone any insight on this problem? Or if anyone has a more specific datasheet for cummins governors other than the official manual, that would be appreciated. Thanks
Also, i find it weird that when the terminals for idle and run are connected, its running at rated, and when idle is disconnected from run, it runs at rated.

 

[Lucien Nunes]

When running at correct speed, does the set take load? Is the frequency within limits?

Stiffness of the actuator linkage or rack can cause odd effects if the actuator can't move it smoothly. It may settle in one of its most common positions where it is more worn, but not want to move away, which would tend to make itself known through overspeeds / stalls etc but this might not happen if the rack is sticking nearly closed and the set is unloaded. Double-check for high-resistance connections in all cables to the actuator and controller. E.g. when hot and malfunctioning, with one actuator and speed sensor lead removed can you see the correct coil resistances with good insulation resistance to ground.

 

[PEG]

Hi,is the units start/charge circuit,providing the 24V?

Have you checked that the input 24V and ground,are within parameters?

 

[Hanjun941]

Yes i have checked the voltages, all in order, its so confusing, I'm even considering replacing all the control wires

 

[PEG]

Hi,if the control wiring is in good order,and they can be tested individually,if needed,i would not rush to that.

The two different sides of engine speed control,need to be assessed.

If you ensure the mechanical side is free,operating correctly,and that includes any device on the engine fuel side.

Once this is confirmed,work forwards to the electrical control side,and then to the inputs,those devices receive. For instance,how does the system receive engine speed data? Some have RPM control on multi-position solenoids,and rely on engine governors,to maintain speed.
Some have real-time RPM control,with lag or delay,to allow engine governor to react.

Out of interest,is there any load on the plant? Have you tried it with a known load?

Have you bypassed the idle/run switch,to iron out that,little sucker?

Some of the RPM adjustments,require the main circuit breaker,to be in a specific position.



There are a huge amount and variety of electronic speed control devices,for these units,on Ebay,so i'm guessing they could be troublesome

 

[Megawatt]

Hi,if the control wiring is in good order,and they can be tested individually,if needed,i would not rush to that.

The two different sides of engine speed control,need to be assessed.

If you ensure the mechanical side is free,operating correctly,and that includes any device on the engine fuel side.

Once this is confirmed,work forwards to the electrical control side,and then to the inputs,those devices receive. For instance,how does the system receive engine speed data? Some have RPM control on multi-position solenoids,and rely on engine governors,to maintain speed.
Some have real-time RPM control,with lag or delay,to allow engine governor to react.

Out of interest,is there any load on the plant? Have you tried it with a known load?

Have you bypassed the idle/run switch,to iron out that,little sucker?

Some of the RPM adjustments,require the main circuit breaker,to be in a specific position.



There are a huge amount and variety of electronic speed control devices,for these units,on Ebay,so i'm guessing they could be troublesome

Hi,

So I am currently troubleshooting a cummins generator that only seems to be able to switch from idle and rated speed mode during only after running for about ten minutes, any longer than that everytime i switch back to idle from running, there is no change and when i change it back to rated, the rated speed increases by about 100rpm, i remove the 24v battery and wait for awhile, when i restart the engine, all the settings are wack and I have to tune the governer settings back to normal i.e. idle and rated speed, however the same issue occurs, at the start i can switch modes fine, after awhile, the same problem occurs, I've connected the wires correctly according to Cummins manual and have replaced the governor controller and actuators, has anyone any insight on this problem? Or if anyone has a more specific datasheet for cummins governors other than the official manual, that would be appreciated. Thanks
Also, i find it weird that when the terminals for idle and run are connected, its running at rated, and when idle is disconnected from run, it runs at rated.
View attachment 53996
View attachment 53997

I worked on generac generators and it had a sensor that screw into the engine to help regulate RPM. I had one that when you cranked it started full speed. Does yours have that sensor and it will be magnetic

 

[Hanjun941]

I have resolved the issue, the magnetic pickup speed sensor stops working properly above 60 degrees, i guess it was just faulty

 

[Megawatt]

I have resolved the issue, the magnetic pickup speed sensor stops working properly above 60 degrees, i guess it was just faulty

Good deal that’s what I thought that might be the problem and thanks for letting us know
[automerge]1574602082[/automerge]

I have resolved the issue, the magnetic pickup speed sensor stops working properly above 60 degrees, i guess it was just faulty

Hankun941 those pick up sensors give a lot of problems. When I was working I would have 2 on my truck

 

[Megawatt]

Good deal that’s what I thought that might be the problem and thanks for letting us know
[automerge]1574602082[/automerge]

Hankun941 those pick up sensors give a lot of problems. When I was working I would have 2 on my truck

When you pulled it out did it have metal shavings stuck to it Because it’s so close to the flywheel ?

 

[PEG]

That was in my fourth paragraph,so i'll pm my paypal details...???

Nice result,and fair play for posting the ongoing story.....some of us don't bother with facebook and love island,so this is what we wait for ?

 

[Megawatt]

That was in my fourth paragraph,so i'll pm my paypal details...???

Nice result,and fair play for posting the ongoing story.....some of us don't bother with facebook and love island,so this is what we wait for ?

DPG my friend I don’t ya Facebook page. I went to school on Generac generators for commercial and industrial units. I didn’t read your comment but the main thing is you got him going nice job

 

[Hanjun941]

I didnt think it was the magnetic pickup, because the correct rpm would show on the speedometer, I cleaned the mpu but it was the same problem, i realised it was the temperature thing, when i took it out again and cooled it, and it worked fine until it got hot again.

 

[Megawatt]

I didnt think it was the magnetic pickup, because the correct rpm would show on the speedometer, I cleaned the mpu but it was the same problem, i realised it was the temperature thing, when i took it out again and cooled it, and it worked fine until it got hot again.

Han great job generators can do some funky things and I went to school on Generac generators and when I was working in the field, got called to this job and it took me hours to find out the problem which was the pick up tube