We have a LM6000 PG. We have had issues with the variable geometry for some time. We have worked through most of the issues but we are currently getting stumped by the VBV Voltage Sum Fault.
We get this alarm at random times mostly on a start up or shut down. We have Woodward MicroNet Plus controllers the card part number that drives the LVDTs is 5501-1432
We have worked through the GE trouble guide and ended up replacing the on and off engine cables as requested by GE we have replace the LVDTs and done countless VG Cals. We have swapped the driver card in between the VSV and VBV the problem did not follow the card.
I have taken a DMM and dropped the lines to the LVDTs from the FTM connected into the leads with spring nuts and ran a long jumper into the package connected to the DMM with banana plugs; then attempted to pull push on the connectors wile watching the DMM for deflection. We also had GE bring a manual pump and pump the VBV to 25% 50% 75% and 100% and attempt to pull push on the connections in attempt to recreate the issue yet keep coming up empty handed.
When I read the LVDT with a DMM the values are P1=108.6Ω S1=74.2Ω S2=72.8Ω plus or minus a few 10ths of a ohm across all my LVDTs. I get the same readings also within a few 10ths directly at the LVDT and at the FTM in the MTTB.
<b>Moderator's Note:</b> Not sure what symbol belongs instead of "Ω". Will try to find out.
We also have a issue of not building enough ps3 for sprint to turn on at this point I think it may be to issues with the VBVs letting to much air out of the engine. GE has provided us a schedule of the amount the VBVs should be open and we are within that proper range of approx 25% open at full load but I am having a hard time believing we should be 25% open when our trouble shooting manual and all the text I have found online says that over 33MW or 60% load the VBVs should be closed..
One more thing.. On the HMI the actuator ohms reads approx 40 on A channel and approx 20 on B channel across IGV, VSV, and VBV. I have pulled a new LVDT verified its values with a DMM and placed it on A channel and it will read 40 ohms then moved that same LVDT to B channel and it will read 20 ohms..
Any one have any ideas??
We get this alarm at random times mostly on a start up or shut down. We have Woodward MicroNet Plus controllers the card part number that drives the LVDTs is 5501-1432
We have worked through the GE trouble guide and ended up replacing the on and off engine cables as requested by GE we have replace the LVDTs and done countless VG Cals. We have swapped the driver card in between the VSV and VBV the problem did not follow the card.
I have taken a DMM and dropped the lines to the LVDTs from the FTM connected into the leads with spring nuts and ran a long jumper into the package connected to the DMM with banana plugs; then attempted to pull push on the connectors wile watching the DMM for deflection. We also had GE bring a manual pump and pump the VBV to 25% 50% 75% and 100% and attempt to pull push on the connections in attempt to recreate the issue yet keep coming up empty handed.
When I read the LVDT with a DMM the values are P1=108.6Ω S1=74.2Ω S2=72.8Ω plus or minus a few 10ths of a ohm across all my LVDTs. I get the same readings also within a few 10ths directly at the LVDT and at the FTM in the MTTB.
<b>Moderator's Note:</b> Not sure what symbol belongs instead of "Ω". Will try to find out.
We also have a issue of not building enough ps3 for sprint to turn on at this point I think it may be to issues with the VBVs letting to much air out of the engine. GE has provided us a schedule of the amount the VBVs should be open and we are within that proper range of approx 25% open at full load but I am having a hard time believing we should be 25% open when our trouble shooting manual and all the text I have found online says that over 33MW or 60% load the VBVs should be closed..
One more thing.. On the HMI the actuator ohms reads approx 40 on A channel and approx 20 on B channel across IGV, VSV, and VBV. I have pulled a new LVDT verified its values with a DMM and placed it on A channel and it will read 40 ohms then moved that same LVDT to B channel and it will read 20 ohms..
Any one have any ideas??