A GE-TM2500 SAC is operating now. We had replaced HPT speed pic-up three times due to sensor failure. sensor’s wiring has been checked as well.

For more information below some details:
- Machine controlled by Woodward
- sensor supply voltage: 24 Vdc
- sensor type: Transducer motion pic-up, P/N: L44920p01 with 187Ohm impedance

Any suggestions to verify sensor fail reasons?

Through my search for solution I read in Woodward manual that some controllers has impedance less than 300 ohm, A 300 ohm resistance should be placed in series with the sensor. Should we do this action? Is that going to effect on the sensor precision?

Appreciate your feedback

 

Woodward Technical support has always been very helpful when I've had to contact them. I won't say I always liked the answers I got (which conflicted with their documentation in several cases) but they were almost always able to offer some useful insights or work-arounds.

Please let us know what you learn and how you resolve the problem.

 

Magnetic Controls Inc in LA, manufactures Mag pickups for many industries. They would be specialists in your failure analysis research and solution.

 

Has anyone find a solution for this. I am having a similar problem. We have a NPT A and B speed probe, each on opposite side of the package. NPT B speed probe goes back to our Woodward control and Bently. NPT A goes back only to Woodward controls. NPT B has consistently fail after a few months of the turbine running. We have tried changing the probe, cleaning the connector and even swap termination position so the other probe goes back to the Bently and Woodward. Each time it will run a few months before it fails again.

I appreciate any feedback for this problem.

 

Hello,

It can be said at this point of time, that both of you can be assumed not using the same MPU (magnetic pick-up).

Unless otherwise, it would be good if you can give more details information about the MPU.

Manufacturer:
Model:
Part No.:
Serial No.:

For my end here, I don't have much experience about repetitive MPU failure(s).

The best way I can think of :-

1. You collect back all the MPUs that failed.

2. Write up some official letter and history (date installed and length of service) about the MPU

3. Courier it to the exact manufacturer to request for 'forensic' investigation...i.e maybe the MPU manufacture can cut the tip and take a very close look what sort of failure i.e overheated, intermittent sparks...etc..this is just an idea...

However, I think sending the MPUs back the its original manufacturer as a good starting point to understand the problem(s) from material point of view, damage mechanism and maybe quality of the manufacturing itself or maybe something to do with field configuration or its operation.

By the way, I assumed your GT has also these Bently Nevada proximity probe for this package...how these probes conditions since the beginning...having some failure also ?

With that, I hope you will discovered something soon and really appreciate can be shared what are the findings.

Best regards.