CAT Titan 250 Manual De Usuario

Turbomachinery Package Specification 

250 Generator Set 

The start system includes a direct-drive AC starter motor driven by a solid-state variable 
frequency drive (VFD). The start system provides torque to initiate engine rotation and to 
assist the engine in reaching a self-sustaining speed. The starter motor is mounted 
directly on the gas turbine accessory drive gearbox. The VFD regulates voltage and 
frequency to the starter motor for engine rotation as commanded by the Turbotronic 4 
control system. 

To begin gas turbine rotation, the VFD initially provides low-frequency AC power to the 
starter motor. The VFD gradually increases the speed of the starter motor until the gas 
turbine reaches purging speed. When purging is completed, the control system activates 
the fuel system. The speed of the starter motor is gradually increased until the gas 
turbine reaches starter dropout speed. The VFD then deenergizes the starter motor and 
the motor clutch assembly is disengaged. 

The starter motor (Figure 7) provides high breakaway starting torque and acceleration 
from standstill to starter dropout speed. The motor is standard frame size and is 
constructed to be explosion proof and flameproof. The motor includes an integral  
over-temperature protection thermostat connected to the Turbotronic 4 control system for 
hazardous area motor certification and protection. Separate cable entry points are 
provided for power connections, thermal protection wiring, and the space heater wiring. 
Starting power is transferred to the gas turbine via the reduction-drive gearbox and over-
running clutch and shaft assembly. After a shutdown, the starter motor rotates the turbine 
at low speed to prevent deformation of the rotor during cool down. 
 

                    

 

 

© 2008 Solar Turbines Incorporated. All rights reserved. 

TPS250GS/908 - Preliminary 

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