Abstract: An apparatus comprising: a flywheel; a shaft; a bearing arrangement for supporting the shaft; a sealing arrangement; and a housing for housing the flywheel, the shaft, the bearing arrangement and the sealing arrangement, wherein the flywheel is mounted on the shaft, the sealing arrangement is mounted between the shaft and the housing, and the bearing arrangement is mounted both to the shaft, between the flywheel and the sealing arrangement, and to the housing; and wherein the sealing arrangement comprises a pair of seals that are configured to extend circumferentially around the shaft, the seals being arranged to form a hermetic seal against the shaft to hermetically seal the housing.

Abstract: An apparatus comprising: a flywheel mounted on a flywheel shaft; a bearing arrangement on which the flywheel shaft is supported; a gearing arrangement for torque coupling the flywheel to a drive member; a sealing arrangement; and a housing for containing the flywheel, bearing and gearing arrangements, the gearing arrangement being arranged to be in torque transmitting engagement with the flywheel, via the flywheel shaft, and having an engagement means for being in torque transmitting engagement with the drive member, the sealing arrangement comprising a pair of seals, defining a cavity, and forming a hermetic seal, between the engagement means and the housing, whereby, in use, a first pressure is maintained within the housing that is lower than a second pressure outside of the housing, and the seals retain a fluid within the cavity, and maintain the fluid at an intermediate pressure between the first and the second pressure.

Abstract: An apparatus comprising: a flywheel mounted on a flywheel shaft; a bearing arrangement on which the flywheel shaft is supported; a gearing arrangement for torque coupling the flywheel to a drive member; a sealing arrangement; and a housing for containing the flywheel, bearing and gearing arrangements, the gearing arrangement being arranged to be in torque transmitting engagement with the flywheel, via the flywheel shaft, and having an engagement means for being in torque transmitting engagement with the drive member, the sealing arrangement comprising a pair of seals, defining a cavity, and forming a hermetic seal, between the engagement means and the housing, whereby, in use, a first pressure is maintained within the housing that is lower than a second pressure outside of the housing, and the seals retain a fluid within the cavity, and maintain the fluid at an intermediate pressure between the first and the second pressure.

Abstract: Apparatus for containing a flywheel comprising: a flywheel; a shaft; a bearing arrangement for supporting the shaft; and a housing for housing the flywheel, the shaft and the bearing arrangement; wherein the flywheel is mounted on the shaft, the shaft is mounted to the bearing arrangement, and the bearing arrangement is mounted to the housing; wherein the flywheel has a rim formed by a circumferential face of the flywheel, and a hub formed by a central region of the flywheel, the hub being wider, axially, than the rim such that a circumferential contact surface is formed by the hub that is coaxial with the rim; wherein the housing comprises an annular force transfer region that faces, and is concentric with, the contact surface; and wherein, in use, excessive radial movement of the flywheel results in the contact surface contacting the transfer region.

Abstract: An apparatus comprising: a flywheel; a shaft; a bearing arrangement for supporting the shaft; a sealing arrangement; and a housing for housing the flywheel, the shaft, the bearing arrangement and the sealing arrangement, wherein the flywheel is mounted on the shaft, the sealing arrangement is mounted between the shaft and the housing, and the bearing arrangement is mounted both to the shaft, between the flywheel and the sealing arrangement, and to the housing; and wherein the sealing arrangement comprises a pair of seals that are configured to extend circumferentially around the shaft, the seals being arranged to form a hermetic seal against the shaft to hermetically seal the housing.

Abstract: An AC generating system having a power source, a controller, and an energy storage subsystem including a rotatable flywheel connected to an electrical machine which is operable to convert flywheel rotation into electrical energy and vice versa, the energy storage subsystem to transfers energy from or to the generating to maintain a target state of charge of the flywheel. The controller is arranged to monitor the AC frequency of the output power from the power source and to feed in power or extract power from the energy storage subsystem into the generating system to counteract relatively short term frequency errors due to changes in demanded load on the AC generating system. Or the power source and energy storage subsystem may be interconnected via a DC bus, and wherein the controller is arranged to monitor the DC power or voltage on the bus against a target power.

Abstract: A transmission for an energy storage and recovery system comprises a variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.

Abstract: The invention relates to an energy storage and recovery system (ERS) coupleable to a prime mover and to an energy storage flywheel. The ERS has a hydrostatic arrangement with a first pumping element and a second pumping element. The pumping elements have a respective fluid displacement and a fluid coupling arrangement for the transfer of fluid power between the first and second pumping elements. The ERS also includes a differential device comprising at least three inputs, wherein a first driveshaft of the first pumping element is coupled to a prime mover in use, a first input of the a differential device is coupled to said prime mover in use, a second input of the differential device is coupled to a second driveshaft of the second pumping element, and the third input of the differential device is coupled to a flywheel in use.

Abstract: An energy storage and transmission system (ESRS) (69) comprises a transmission (9, 11) and an energy storage device such as a flywheel (1). While energy is being transferred between the energy storage device (1) and an energy source/sink (7), the transmission ratio of the transmission (9, 11) will usually be changing constantly. In order to manage the torque applied by the energy transfer device (1) or the power transferred, a controller (100) responds to discrepancy between the torque or power supplied and the torque or power demanded.

Abstract: The invention relates to an energy storage and recovery system (ERS) coupleable to a prime mover and to an energy storage flywheel. The ERS has a hydrostatic arrangement with a first pumping element and a second pumping element. The pumping elements have a respective fluid displacement and a fluid coupling arrangement for the transfer of fluid power between the first and second pumping elements. The ERS also includes a differential device comprising at least three inputs, wherein a first driveshaft of the first pumping element is coupled to a prime mover in use, a first input of the a differential device is coupled to said prime mover in use, a second input of the differential device is coupled to a second driveshaft of the second pumping element, and the third input of the differential device is coupled to a flywheel in use.

Abstract: A transmission for an energy storage and recovery system comprises a variable slip transmission and a clutch arranged to transmit drive while slipping. The level of torque transmitted through the slipping clutch is dependent on the clutch force but is independent of the clutch slip speed. Preferably the clutch is provided by a plurality of clutches connected in parallel in a range extender. When drive is transferred between clutches in parallel, the clutch forces of both clutches are controlled to maintain the total torque transmitted by the clutches. This reduces torque fluctuations at the energy source/sink during clutch transfer. Where there are two slipping clutches in series, one clutch is controlled to provide the required torque and the other clutch is controlled in response to a clutch slip speed. This helps to control the speed of rotation of the mass between the clutches.