Hello my friends model railroader
hearing the sound of the tsunami GE gas turbine at the very beginning I think I heard a diesel engine if it is fact, this engine was to crank the turbine?
It was there to shuttle the loco around the yard.
David B
Based on my aviation experience with turbines, I would not expect a diesel engine to be used directly as a starter. A small diesel would probably power an air compressor or more likely a generator which would supply the energy to spin the electric or compressed air starter motor on the turbine. A diesel is preferred to gas because most diesels and tubines can share the same fuel.
A turbine is started by spinning it up to about 15-20% of operating RPM with an electric or air motor - and keeping it there. Once RPM is up to the level required for start, fuel is introduced rather slowly to accelerate the turbine to operating RPM and temperature. If fuel is brought in too early, or too much fuel is introduced during the start, the turbine “hot starts” and overtemps. The start must be aborted, and another try made after everything cools a little. If the first attempt at a start is a hot start, it is that much easier for subsequent start attempts to be hot, too.
Starting a turbine (turboshaft, turboprop, or fanjet) is typically about a 15-20 second (per turbine) carefully monitored process.
Unless the turbine is small, a battery does not supply enough power to get the turbine going. An external power cart (diesel generator), or the aircraft’s own auxiliary power unit (a small turbine genset started by battery or compressed air reservoir) is needed to supply enough power to start the main turbines.
Fred W
The pony deisel engine provided electrical power to operate the locos systems like the air compress., fans, and lights when the turbine was not running, as well as to hostle the loco around the yard,
While the aux diesel was not directly connected to the turbine, it provided power in the form of air, to get the turbine spinning, and the turbine also operated on diesel fuel during start up.
Once the RPMs and temp were high enough, the fuel was switched to bunker c fuel.
According to this link, http://en.wikipedia.org/wiki/Union_Pacific_GTELs, “For starting, the unit’s auxiliary diesel generator would be used to power a set of windings installed within the gas turbine’s main generator, causing the generator to rotate. The main generator’s rotation would begin to spin-up the turbine, at which point diesel fuel would be used to start combustion.”
In response to a couple of posts on this subject.
I was a commercial pilot for years and to start a modern turbine, you’d energize the generator and it would spool up the tubine until you reach a specific RPM, then you’d introduce fuel. You’d monitor the EGT and as soon as the turbine is self sustaining, you’d disengage the starter(generator), and shut off the igniters.
The engine is now self-sustaining and will run as long as it has an uninterrupted fuel supply. Switch on the generator so you have electrical generation, and you’re good to go!
It was VERY important to have a good solid supply of power to the starter to spool up the unit as quickly as possible, helping avoid a “hot start” which menas an automatic teardown and overhaul of the power (hot) section. Often, the airplane’s batteries were iffy at best, and we were encouraged to use ground power as often as we could.
I read somewhere that the UP used small diesel engines to provide a source of power to spool up the turbine?
One of my great regrets is that I never saw one of those beasts in action. Even though I detest the UP, :), I do appreciate their experimentation and willingness to try something new.
Thanks, I learned a lot about the gas turbine
thanks david
tankes maxman
Thank you my friend
Thank you my friend CP guy in TX