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MARK I Card Calibration
Need some materials on mark I calibration

Hi,

I'm going to go to an old power plant with an ALSTHOM frame5 unit with mark I control system. They have some serious problem with turbine. For example as they told, unit goes to overspeed or SRV, GCV fluctuation. They want me to calibrate the speedtronic cards, and honestly I haven't done this yet. So I would be grateful if somebody give me some instruction and materials related to this topic. There would be instructions in manual but I want to be prepared somewhat before going there.

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dontknowman,

The main document(s) you will need is the Control Specification. This may consist of more than 1 document - my sometimes faulty memory thinks 3 documents were supplied back in Mark I days. At least 1 of them is necessary to calibrate the analog control cards.

I also suggest you ask if there is a functioning Mark I calibrator available on site. This will make the job much easier, as it incorporates some useful devices like a variable frequency pulse generator to simulate magnetic speed pickups, and may include a millivolt source for thermocouple inputs. Ask if they can provide the supporting documentation for the calibrator, so you at least understand what it can (and can't) do.
You are likely to need replacement circuit cards, so ask about availability of spares. Expect to find faulty electrolytic capacitors. This control is surely over 40 years old and electrolytic capacitors dry out and fail. You might also ask if their spares are old, since the electrolytics on them will be suspect - they dry out more quickly sitting on the shelf than if they are used.

You need a small screw driver to adjust the potentiometers on the cards, and a good VOM (Fluke). If you will be expected to troubleshoot and repair the cards, you may find an oscilloscope useful, as well as a soldering iron and a solder sucker. The cards are not multilayer, although they may have traces on the top of some cards. A card extender would also be needed to troubleshoot a card while it is in the panel and powered up. Make sure the site has "backsheets" (circuit diagrams) for the cards.

Good luck!

1 out of 1 members thought this post was helpful...

There were three sections to the Control Specification drawing back then:

Control System Settings
Control System Adjustments
Operating Instructions and Sequences

You will likely need the first two documents at a minimum.

And, a Mark I calibrator will be key. Or several simulators at a minimum. And, a good multi-meter (True AC RMS).

"Back-sheets" were pretty common back then, but I don't know if anyone's scanned them into an electronic file and can send a copy. Perhaps glenmorangie? (bbobjohnston@gmail.com, if I recall correctly.)

And, if I recall correctly, a LOT of problems with Mark I and Mark II Speedtronic turbine control systems were caused by power supply problems.

Finally, as otised mentioned, working on Mark I/Mark II required a good knowledge of basic electronics, and soldering. A lot of components could be replaced easily if one could use a soldering iron (and one had access to the right replacement components).

Hopefully, glenmorangie has scanned copies of the Mark I information/backsheets.

I have two Mark I GE supplement manuals that have the Control/Calib Specs and operating sequences. I could scan what pages you need--

1 out of 1 members thought this post was helpful...

> I have two Mark I GE supplement manuals that have the Control/Calib Specs and
> operating sequences. I could scan what pages you need--

Warning:
The "Control Systems Settings" document is different for each site and for each Frame size unit at any site.

The "Operating Instructions and Sequences" is probably different for each site and frame size.

The "Control System Adjustments" document may have been a standard document or may have been customized for each site and frame size - I don't remember.
Back in those days, there was a lot more site specific documentation than there is now!
Using documentation from a different site may be useful for getting an understanding of the processes and procedures, but you will need the correct site documentation to actually do the work.

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Calibrating a Mark I is a very complex process. I could write for hours on Mark I calibration details. If this is your first time, You will need thermocouple wire for the exhaust thermocouple averaging cabinet, special jumpers for the Mark I wiring, 2 thermocouple simulators, frequency generator. Also you will need very accurate and calibrated VOM and a knowledge of the turbine start sequence.

The Mark I is pre-integrated circuit and cards can be repaired, but you will need the Mark I card reference manual. The Calibration manual is straight forward and detailed. CSA was very correct in stating that a calibration simulator helps...helps a ton...but when moving jumpers on the simulator one can basically destroy some hard to find cards..

Good luck

Thank for all your help in this topic.

I went to that powerplant and fortunately (or maybe unfortunately!!) a very knowledgeable man on old speedtronic systems accompanied me. With his remarkable help we did that, but we had no valid reference; and the volume which was there had not that unit control specifications. We just did a little change in constants. However, I wrote this for feedback and appreciating anyone who help others in this useful site.