Rotation coupling employing torque converter and synchronization motor

A method comprising:

• (a) using a torque converter to cause a drive element to rotate a load element;
• and
• (b) using a motor to substantially synchronize the rotational speeds of said drive and load elements,
• said drive element rotating at a first substantially constant speed during steps (a) and (b),
• step (a) including using said torque converter to cause the rotational speed of said load element to increase from at or near zero revolutions per minute (rpm) to a second rotational speed within about 20 percent of said first substantially constant speed,
• step (b) including using said motor to increase the rotational speed of said drive element to a third rotational speed greater than said second rotational speed and within about 5 percent of said first substantially constant speed.

A method of starting a compressor powered by a gas turbine, said method comprising:

• (a) using said gas turbine to rotate a drive shaft without rotating a load shaft that drives said compressor;
• (b) subsequent to step (a), using a torque converter to transmit torque from said drive shaft to said load shaft, thereby causing rotation of said load shaft so that the rotational speed of said toad shaft is less than the rotational speed of said drive shaft;
• (c) simultaneously with step (b), using an electric motor to increase the rotational speed of said load shaft until the rotational speeds of said drive and load shafts are substantially synchronized;
• and
• (d) while the rotational speeds of said drive and load shafts are substantially synchronized, mechanically locking said drive and load shafts to one another.

A method of starting a compressor powered by a gas turbine, said method comprising:

• (a) using said gas turbine to rotate a drive shaft without rotating a load shaft that drives said compressor;
• (b) subsequent to step (a), using a torque converter to transmit torque from said drive shaft to said load shaft, thereby causing rotation of said load shaft;
• (c) simultaneously with step (b), using an electric motor to increase the rotational speed of said load shaft until the rotational speeds of said drive and load shafts are substantially synchronized;
• and
• (d) while the rotational speeds of said drive and load shafts are substantially synchronized, mechanically locking said drive and load shafts to one another,
• step (a) including increasing the rotational speed of said drive shaft from at or about zero to a first rotational speed of at least about 1,000 revolutions per minute (rpm),
• step (b) including increasing the rotational speed of said load shaft from at or about zero to a second rotational speed less than said first rotational speed but within about 10 percent of said first rotational speed.

An apparatus comprising:

• a rotational driver;
• a rotational load;
• a drive element rotatable by said driver;
• a load element for rotating said rotational load;
• a torque converter for transmitting torque from said drive element to said load element;
• and
• a synchronization motor drivingly connected to said load element and not to said drive element and operable to increase the speed of rotation of said load element when used in combination with said torque converter and when the load element is being rotated by the torque convener,
• said synchronization motor being unable to rotate said load element without torque being transmitted by said torque converter.