Permanent motor generator band brakes

A system comprising:

• a permanent magnet generator (PMG) with a generator shaft defining a longitudinal axis;
• a brake system, wherein the brake system includes a brake shaft with a first end operatively connected to the generator shaft for selectively rotating with the generator shaft or braking to slow the generator shaft;
• and
• a shear shaft operatively connected to a second end of the brake shaft axially opposite the first end along the longitudinal axis, the shear shaft configured for connection to a prime mover for rotation of the generator shaft, the shear shaft also configured to rotate together with the prime mover and with the brake shaft under normal conditions and to disconnect the prime mover from the brake shaft if subjected to a predetermined torque differential between the prime mover and the brake shaft;
• wherein the brake system includes a band with (i) a first position radially withdrawn from the brake shaft and (ii) a second position radially pressed against the brake shaft for applying braking forces to the brake shaft and to the generator shaft, wherein the brake system includes an actuator operatively connected to the band to actuate the band from the first position to the second position;
• and
• wherein the band is configured so that contact with the brake shaft urges the band toward tightened engagement of the band toward the brake shaft due to a rotation direction of the PMG.

A system comprising:

• a permanent magnet generator (PMG) with a generator shaft defining a longitudinal axis;
• a brake system, wherein the brake system includes a brake shaft with a first end operatively connected to the generator shaft for selectively rotating with the generator shaft or braking to slow the generator shaft;
• a shear shaft operatively connected to a second end of the brake shaft axially opposite the first end along the longitudinal axis, the shear shaft configured for connection to a prime mover for rotation of the generator shaft, the shear shaft also configured to rotate together with the prime mover and with the brake shaft under normal conditions and to disconnect the prime mover from the brake shaft if subjected to a predetermined torque differential between the prime mover and the brake shaft;
• and
• a generator control unit (GCU) operatively connected to the PMG and configured to control electrical output of the PMG, the GCU comprising machine readable instructions configured to cause the GCU to:
• receive input indicative of an electrical fault condition for the PMG and enter into a braking mode based on the input indicative of the electrical fault condition;
• and
• output a command to a servo valve for dynamic control of the brake system for dynamically applying braking to the generator shaft;
• wherein the brake system includes a band with (i) a first position radially withdrawn from the brake shaft and (ii) a second position radially pressed against the brake shaft for applying braking forces to the brake shaft and to the generator shaft, wherein the brake system includes an actuator operatively connected to the band to actuate the band from the first position to the second position;
• and
• wherein the PMG is configured to be driven in a rotational direction, wherein a first end of the band contacts the brake shaft along a tangent in the second position, wherein a second end of the band contacts the brake shaft along a tangent oblique to the first end of the band, and wherein the first and second ends of the band are oriented so that contact with the brake shaft urges the band toward tightened engagement of the band toward the brake shaft due to the rotational direction of the PMG.