摘要 |
<p>An uninterruptible power supply system (44) has standby and backup modes and can change to backup mode upon detection of a grid fault. In both modes an alternator (14) rotates at synchronous speed so that backup mode capability is ready. An energy storage unit (54) remains coupled to the grid (38) in standby mode so that it is charged, ready to supply power when changed to backup mode. In standby mode, first and third clutches (48, 52) are disengaged and engaged, transmitting alternator rotary motion to a flywheel (46) but not therefrom to a heat engine (12). In backup mode, first and third clutch (48, 52) are engaged and disengaged to permit the alternator (14), via a second clutch (50), to overrun the flywheel (46) and allow transmitting of flywheel torque to accelerate the heat engine (12) to starting speed for driving the alternator (14) to supply power to the grid (38) after the engine (12) is at operating speed and coupled to the alternator (14) through the locked second clutch (50) and engaged with the third clutch (52). <IMAGE></p> |