General Electric unveiled its first electronic control and protection system in 1970. It was called Speedtronic™. Other manufacturers similarly introduced electrical and electronic controls on gas turbines at the about same time. The name for GE’s system came from the combination of Speed control by elecTronic. I’ve had difficulty confirming who came up with the name, but it has prevailed for over four decades up to modern times. The first generation was called Mark I. GE currently offers the sixth version, Mark VIe, a computerized version that will be discussed in later chapters.
The first gas turbines to utilize Speedtronic™ controls to drive generators were the MS5001M and MS7001A turbines as prototypes in 1969-70. Several so called “Mary” machines, as the frame 5’s were nicknamed, were typically sold in 4-unit power blocks. Most notable were the eight turbines installed by Niagara Mohawk in nearby Rotterdam, NY, only a few miles west of the GE plant in Schenectady. I believe the very first Mary went to Public Service on New Hampshire in the northern part of the state. Long Island Lighting purchased the first “7A” machine, after considerable testing of this “first of a kind” was done at the Schenectady Works plant. It was installed at the Shoreham site on Long Island. It was the only Frame 7 ever built in Schenectady.
In 1971, the first MS5001N machines (frame 5 nicknamed “Nancy” machines) and MS7001B turbines were commissioned with Speedtronic™ controls. Many 5N turbines were sold in their first year of production: for instance, Consolidated Edison Co. purchased 48 of them for floating power barges in the East River in Brooklyn, NY at the Gowanus and Narrows sites. Many others were installed at utilities in the USA, particularly in small towns. For instance, Pennsylvania Power & Light operated a 2-unit power block in Sunbury, PA and installed a 4-unit power block in Martins Creek, PA in that year. All had Mark I controls.
The 7B machines were very popular also as hundreds were sold to electric utilities and industrial power generation plants in the USA and abroad mainly because of the higher generating capacity. Venezuela’s government-owned power company called CADAFE purchased many 7B machines, as one of GE’s most important international clients. A typical Speedtronic™ panel for a 7B is shown in Fig. 13-3.
In the next photo, Fig. 13-4, the electronic circuit boards are shown configured in rows and columns. Approximately 70 circuit boards were required, depending upon the model and features of a particular turbine. Dual fuel systems used the most controls circuit boards with diesel engines and “black start” capability required the most boards.
Also known as “cards,” the circuitboards were configured into rows (top to bottom) and columns (A-T., right to left). As Fig. 13-5 shows, there are many different types of boards with different fascia, depending upon the function of each. All cards had 51 pins on the back plane for electrical wire connections. This door was referred to as the Speedtronic™ Page, as it resembled a page in a book. The Page was called Page 1L in the turbine electrical elementary drawings.
Many of the circuit boards were in existence when applied to gas turbines, originally used in commercial systems and manufactured at GE’s Salem, Virginia plant. The generic name was Directomatic II for the cards. Popular cards included: input buffers, operational amplifiers, relay drivers, light indicators and clock drivers. Other cards, as shown in Fig. 13-5, had to be specially made for gas turbine applications, for instance: SSKA was used for gas turbine start-up control, with all the red test buttons shown on the left in position page 1L, row 1, column P. This location was usually abbreviated simply: [1L1P]. This card sets fuel limits by setting a control signal called Variable Control Voltage (VCE). Note: voltage is also known as electromotive force (EMF). Thus, the letter is E in the abbreviation, instead of V.
In Fig. 13-5 above, notice the cluster of green cables at the right. They provided the interconnections to outside signals, including the relay page called 2L. It is shown on a door behind the Speedtronic™ door below in Fig. 13-6. There are approximately 50 DC relays (shown in the middle, brown in color) and a dozen timers (shown at the top). They are configured in rows (0-7, top to bottom) and columns as well.
The relays are the “plug-in” type and can be replaced if necessary should one fail in operation. The timers are adjustable and serve many applications where a timed operation is required. For instance, the hydraulic ratchet on a MS5001N machine has a 3-minute cool-down cycle, hence the setting of timer 2HR.
The Speedtronic™ panel could be calibrated by field engineers, as shown in Fig. 3-7. A special calibrator tool was provided by GE that could be connected into the panel, as shown. Dave Lucier, of PAL Turbine Services, LLC, performs a calibration for Aquila in Jefferson City, MO. It provided both analog and digital signals for speed, temperatures and DC voltages that are used as “inputs” to circuit boards shown in the lower half of the panel in Fig. 3-7. The calibrator could also be used to simulate operation of the gas turbine when desired.
Most control systems of this era were also accompanied with a protection system that included an annunciator as shown below in Fig. 13-8. A lamp would flash and an audible sound would alert the plant operator should an adverse condition arise or a shutdown signal be initiated. Crude by modern standards, this type of system was very common during the 1970s era. Tag names on the annunciator light would alert the operator as to the problem; from there, the operator could consult an instruction manual so and take the action required.
Certainly crude by modern standards, Speedtronic™ Mark I and Mark II were offered by General Electric for decade of the 1970s. The technology can be traced to the developments in analog and digital controls that evolved in the late 1960s, perhaps as a consequence of the space race that lead to men landing on the moon in 1969. General Electric was certainly a pioneer in the application of these developments to gas turbines.