Abstract: A brushless excitation system for a synchronous dynamoelectric machine includes an alternating current exciter and a rotating rectifier assembly. In such a system, the alternating current exciter includes a salient pole stator field member and a polyphase armature rotor member. A sensing coil is disposed around at least one of the salient stator poles for developing an alternating electrical signal in response to changes in the magnetic flux wave linking the rotating armature member and the field coil of the salient stator pole member. Means connected to the sensing coil indicates variations in the alternating current signal which correspond with disturbances in the rotary electric circuit of the brushless exciter such as a line-to-line short circuit or a phase-to-phase short circuit in the armature winding, or shorted diodes or open fuses in the rotating rectifier assembly.

Abstract: A large starting motor is provided, especially for reversible, pumped storage water wheel generator-motor units, having a rotor member which comprises a relatively thin ferromagnetic rim and a closed container of cooling fluid disposed adjacent and radially inward thereof. Heat developed due to circulation of starting currents within the rim is conducted to the cooling fluid through the inside diameter surface of the rotor rim. Provision is made for venting and replenishing the cooling fluid which heats up and in extreme cases vaporizes in response to the thermal energy transferred from the rim.

Abstract: Two cascaded induction machines provide asynchronous power transmission between two independent generating networks. The shafts of the two induction machines are mechanically connected for concurrent rotation and the rotor windings of the two machines are electrically connected in a reverse phase sequence. The cascaded induction machines are geared to a relatively low power variable speed drive which accurately controls the position and rotation of the shafts. A control system supplies low frequency excitation current for the variable speed drive and is capable of continuous operation through zero frequency to reverse the direction of rotation. The control system determines the level of power flow within the induction machines and is unresponsive to the difference in frequency of generation of the two generating networks so that the power flow is controlled even under transient load conditions.