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Super Contributor

Re: Losing Power 3516 BTA

Yes, that will do it, but you should have been getting a loss of throttle sensor fault in the ECM.  IF the DSLC PWM output fails the ECM will drop the rpm to the programmed idle setting.  But like I said, there should have been a fault code everytime it happened.  Can't remember the fault code off the top of my head, but if you have an EMCP II it is likely a logged fault unless someone cleared it.

Cat Dealer
Dealer

Re: Losing Power 3516 BTA

If you have an emcp 2 control, I would monitor the k1 [electronic governor] relay or the k7 [fuel control relay].     the symptom you describe is consistent with the ignition power being interrupted to the engine ecm.    sort of like turning the key switch in a vehicle off then back on.

Contributor

Re: Losing Power 3516 BTA

Been on leave but the guys have fixed the problem while I was off, it appears that the battery voltage was dropping as the engine loaded up, this being the DSLC load control DC supply it affected the PWM output load signal??? Strange but it now appears to be working fine.

 

Thanks for all the advice.

 

Mike

New member

Re: Losing Power 3516 BTA

 

please check the following:

1. connection on the breaker relay or shunt trip.

2. reverse power relay maybe trigger once unit on load and open the breaker.

3. controller setting, check for accuracy or reverse power setting

 

 

Highlighted
Contributor

Re: Losing Power 3516 BTA

This unit must be in parallel with another source to get a reverse power trip? Or the load has a very high inertia?

Reverse power is not necessarily an engine problem, so it does not need to shutdown the engine.

 

I agree with the others...try fuel quality, combustion air, it could be something besides the controls. Or maybe the other unit is going high, either Hz or V.

 

Does it drop the load first (low Hz?) before it gets the reverse power or does it reverse power and than drops the load?

 

The AVR output going high should cause an overexcitation or overvoltage alarm, not a reverse power.

If the AVR goes low, then it could result in a reverse power trip, but it should first trip on underexcitation or undervoltage.

 

Did this start suddenly or with some other event, like a PM service or something?

 

Good luck!

Steve  

 

 

Contributor

Re: Losing Power 3516 BTA

It was one of our experts that had me fooled, it shut down again on reverse power after 3 hours..back to square one..Am setting up a recorer to monitor some of the numbers
Super Contributor

Re: Losing Power 3516 BTA

Sounds like you found your problem, but I'm confused about some of the information you provided.  An AVR going to a high output and causing as low lagging power factor should not cause a reverse power trip.  The most likely trip would be overcurrent.  The DSLC is a real power controller, and are you also using it to control VAR share?

 

If the AVR went full field then shut off then the loss of field protection should trip, again NOT reverse power.

 

Oh well, at least you found it.

 

Mike L.

Contributor

Re: Losing Power 3516 BTA

An update :: looks like the problem was with the voltage regulator going high causing the unit to go into low lag power factor, the reverse power relay picked up and tripped the breaker. Have replaced the AVR and it is now running okay...Thanks for the advise. Mike
Contributor

Re: Losing Power 3516 BTA

There are two sets of batteries, both have thier own chargers fed from the platform power supply, the battery voltage measured is 25 volts but the ECM displays 24 volts using electronic technician, it is this voltage that shows the ripple. It is the local Cat rep that is recommending the possible ECM replacement. The ECM is mounted on the engine an there are 4 plug connections between the DSLC and the ECM, we have checked all the connections accessable but we have not found any problems. Thanks for the help. Mike Reeby
Super Contributor

Re: Losing Power 3516 BTA

OK, so if you have an alarm indicating a problem with the power supply, and a trend appears to confirm you have a problem with your power that is load related, how does that lead you to an ECM problem?  Was any other testing done, like putting a DMM on the power input to the ECM to see if the power is actually fluctuating or is the ECM incorrectly reporting a problem?

 

Frankly, based on the info provided so far, I would start doing a careful look at all engine wiring connections, especially ground and Battery negative.  Does the unit on-line rely on a charging alternator or a power supply to supply DC when when running?  What are they deviations you report in the power, spikes, dips, swells or sags?  If the power dipping or sagging, you could be affecting the actual fuel delivery and causing the power loss.  If the power is dropping low enough it may actually be reseting the ECM.

 

Before changing the ECM I would do a little more investigation, the ideal tool would be a scopemeter or trending meter with a fast enough response to capture the actual duration and magnitude of the deviations you report, A good quality DMM may work, but be sure it has an analog function or use the MIN MAX record function, or use an analog meter on the correct scale.  Also measure the power supply on the AC scale and look for ripple, if you have a high ripple (above 2 VAC), then measure it's frequency to see if you can define it's source.  Also check your ground connections and generator grounding, as it may be a possible contributor to an erratic DC power problem.

 

Hope that helps, Mike L.