Abstract: A fluid-cooled switched reluctance motor, comprised of a stator having a plurality of evenly spaced, radially oriented, like stator poles that define a gap between adjacent stator poles. The stator poles have side walls that are dimensioned wherein adjacent side walls on adjacent stator poles are parallel. Windings are wound about the stator poles, adjacent windings forming a slot of uniform cross-section therebetween. A rotor element is mounted for rotation relative to the stator. The rotor has a plurality of equally spaced, radially oriented like rotor poles. An elongated cooling tube is disposed within each of the slots defined between the windings. The cooling tube has a first end and a second end, and is dimensioned to essentially fill the slot between adjacent windings. A first coolant chamber is disposed at a first end of the stator, and a second coolant chamber is disposed at a second end of the stator.

Abstract: Index signals which represent the degree of instability in a three-phase induction motor system is derived by using phase current signals which are usually already available in V/Hz PWM inverters for other purposes. Proportional integration compensators, which may be implemented in software, process these index signals and generate frequency and/or voltage adjustments to the V/Hz controller in order to compensate for speed instability in the system. The compensation algorithm is robust to system changes and is also effective to improve acceleration and deceleration performance.

Abstract: A power inverter assembly for a three-phase motor includes a resistor of known resistance which is capable of being switched in between the positive and negative DC bus lines that supply power to the power control electronics. When the resistor is switched in, a voltage drop across the bus lines is observed. The magnitude of this voltage drop is then used to determine a percent impedance value which indicates whether the source impedance is sufficient.

Abstract: A method for dynamically braking a motor, the motor having a plurality of terminals and receiving an input alternating current voltage waveform, by detecting the zero crossing of the input alternating current voltage waveform and for a plurality of position of the input alternating current waveform: sampling a voltage waveform appearing at a terminal of the motor to develop a sampled value for the position, comparing the sampled value for the position to a reference value for the position and setting a flag if the reference value for the position matches the sampled value for the position, introducing a delay period and generating a gating pulse to fire a silicon controlled rectifier to provide a pulse of braking current to the alternating current motor and then halting the braking of the motor if the flags for each of the plurality of positions are set. Also an electronic dynamic brake assembly operable in a SLAVE mode, a PRE-STOP mode, a HOLDING mode and a MASTER mode.

Abstract: An antifreeze arrangement especially for automatic sprinkler systems comprising a frangible membrane, secured to a bellows interposed in the water supply pipe to the sprinkler system, antifreeze solution downstream of the membrane with water upstream thereof, the membrane being one that breaks out but does not separate from the bellows when a sprinkler relieves the pressure on the downstream side. Pressure equalizing piping connections, filling piping, and a specific gravity indicator are provided.