Abstract: A system to reconfigure a motor from induction mode to synchronous mode at a zero crossing of the field voltage during startup using only stator current signals is described herein. The zero crossing may be detected by asymmetry induced in the stator currents by a current asymmetry inducing module of the motor. The current asymmetry inducing module may include a resistor and diode in series and in parallel with a discharge resistor of the field windings. Asymmetry is induced in the current obtained from the stator, and used to determine a zero crossing of the field voltage. Upon the rotor reaching a startup frequency and the detected zero-crossing of the field voltage, the motor may be reconfigured from induction mode to synchronous mode.

Abstract: Signal transducers in electrical communication with shorted leads of current transformers are used to provide monitoring and protection functions to an electric power delivery system. Differential protection is performed by comparing a predetermined threshold against a voltage signal from series-connected leads of signal transducers in electrical communication with shorted leads of current transformers. The signal transducers may be Rogowski coils. Signal transducers in communication with shorted leads may be used to improve safety and increase performance of the current transformers by decreasing susceptibility to saturation.

Abstract: A system to reconfigure a motor from induction mode to synchronous mode at a zero crossing of the field voltage during startup using only stator current signals is described herein. The zero crossing may be detected by asymmetry induced in the stator currents by a current asymmetry inducing module of the motor. The current asymmetry inducing module may include a resistor and diode in series and in parallel with a discharge resistor of the field windings. Asymmetry is induced in the current obtained from the stator, and used to determine a zero crossing of the field voltage. Upon the rotor reaching a startup frequency and the detected zero-crossing of the field voltage, the motor may be reconfigured from induction mode to synchronous mode.

Abstract: A polymer film suited to use as a face mask or transdermal patch includes at least 30 wt. % of a thermoplastic polyurethane polymer which is the reaction product of a first polyether polyol having a molecular weight of at least 3000 daltons, optionally, a second polyether polyol having a molecular weight of no more than 2500 daltons, at least one of a third polyol having a molecular weight of up to 800 daltons, and a chain extender, a diisocyanate, optionally, a catalyst. The film includes up to 5 wt. % water.

Abstract: The thermoplastic polyurethane (TPU) compositions described herein have a very good snap back properties (also called rebound resilience) while still maintaining a good combination of other properties, including hardness, low-temperature flexibility, abrasion resistance, weather-ability, low density, or any combination thereof. This combination of properties make the TPU compositions described herein useful materials for applications where polyamide copolymers (COPA) and/or polyether block amide (PEBA) materials have traditionally been used over TPU.

Abstract: A polymer film suited to use as a face mask or transdermal patch includes at least 30 wt. % of a thermoplastic polyurethane polymer which is the reaction product of a first polyether polyol having a molecular weight of at least 3000 daltons, optionally, a second polyether polyol having a molecular weight of no more than 2500 daltons, at least one of a third polyol having a molecular weight of up to 800 daltons, and a chain extender, a diisocyanate, optionally, a catalyst. The film includes up to 5 wt. % water.

Abstract: The thermoplastic polyurethane (TPU) compositions described herein have a very good snap back properties (also called rebound resilience) while still maintaining a good combination of other properties, including hardness, low-temperature flexibility, abrasion resistance, weather-ability, low density, or any combination thereof. This combination of properties make the TPU compositions described herein useful materials for applications where polyamide copolymers (COPA) and/or polyether block amide (PEBA) materials have traditionally been used over TPU.

Abstract: A clear hydrophobic TPU is provided by reacting (a) a hydrophobic polyol made from dimerised fatty acid, (b) a chain extender mixture of a linear diol chain extender and a branched diol chain extender, and (c) a diisocyanate. The preferred polyol is a C36 dimer fatty acid reacted with 1,6-hexane diol. The preferred chain extender mixture is a 75:25 weight ratio blend of 1,12-dodecane diol and 2-butyl-2-ethyl propane diol. The preferred process to make the TPU is a batch process which starts the reaction between about 60° C. to 70° C.