Good morning everyone.
I want to make enquiry on something.
Is it possible to replace I/O card from Mark 6 core { frame 6B} without powering off the core.
It has turn to an argument at my working place because the VRTD I/O card was bad and the gas turbine hasn't completed on cool down sequence.
But my main question is it Possible to replace the I/O card while the core is still on.

 

Good afternoon

It is mentioned in Mark VI manual that VME rack have to be powerdown for installation of the VRTD card

 

It's NOT a good idea to try replacing I/O cards in a Mark* VI processor rack with the rack in operation. It has been attempted, but with mixed results.

And I only know of sites with Mark* VI TMR panels this was attempted on, not SIMPLEX panels. It's DEFINITELY not recommended for SIMPLEX panels.

As far as cooldown sequence is concerned, as long as the hottest wheelspace temperature is below approximately 250 deg F (approximatey 120 deg C) it is safe to terminate cooldown--with the caveat that the Aux. L.O. Pump should be placed in HAND (manual) operation to maintain L.O. flow to the bearings for cooling purposes. (Bearing babbit begins to soften at approximately 250 deg F, and that's the big concern with terminating cooldown early (which is typically done with Logic Forcing, but could also be done by opening the Hyd. Ratchet Pump motor starter's main breaker, prevening the ratchet mechanism from operating).

If you can crank the turbine to force cool it, that would help reduce the internal wheelspace temperatures (and the axial compressor shaft temperature) quicker.

What problem is the VRTD card experiencing? Are you CERTAIN it's not the wiring interconnecting the RTDs to the Mark* VI or the RTD itself? Or the TRTD? MANY people are completely baffled by the way GE wires three-wire (or four-wire) RTDs to the Mark* turbine control panel with twisted, shielded pair cabling. This topic has been covered before on Control.com, and can be found using the Search feature at the top of every Control.com webpage.