Abstract:
Embodiments of the invention provide a method of operating a motor connected to a power device having a reduced current rating. The motor can include an increased torque constant and/or an increased back electromagnetic force constant in order to decrease a peak current in relation to the reduced current rating of the power device. The method can include increasing a length of time the motor can operate at the peak current without overheating. A phase angle of the motor can be advanced in order to achieve a continuous operating point with the power device having the reduced current rating.
Abstract:
Embodiments of the invention provide methods of controlling a motor, such as a servo motor. One method can include monitoring a current temperature of the motor and a power stage of the motor substantially continuously and substantially in real-time. This method can include determining optimum settings for a first time interval to remove power and the second time interval to provide power in order to deliver maximum output while remaining below the maximum rated temperature of the motor. One method can include pulsing power to the motor for a second time interval after a first time interval has elapsed and tailoring pulse shapes of the power provided to the motor for the second time interval. One method can include calculating a maximum phase current based on the rotor shaft torque for each real-time speed of the motor that correlates to the maximum allowable current draw from the power supply.
Abstract:
Embodiments of the invention provide a fire-extinguishing system and method for injecting foamant into a stream of water. The system can include a flow meter determining a flow rate of the stream of water and a foam pump having an inlet coupled to a supply of foamant and an outlet coupled to the stream of water. The system includes a servo motor driving the foam pump. The servo motor includes a sensor used to determine a rotor shaft speed and/or a rotor shaft torque.
Abstract:
Embodiments of the invention provide a fire-extinguishing system and method for injecting foamant into a stream of water. The system can include a flow meter determining a flow rate of the stream of water and a foam pump having an inlet coupled to a supply of foamant and an outlet coupled to the stream of water. The system includes a servo motor driving the foam pump. The servo motor includes a sensor used to determine a rotor shaft speed and/or a rotor shaft torque.
Abstract:
Embodiments of the invention provide methods of controlling a motor, such as a servo motor. One method can include monitoring a current temperature of the motor and a power stage of the motor substantially continuously and substantially in real-time. This method can include determining optimum settings for a first time interval to remove power and the second time interval to provide power in order to deliver maximum output while remaining below the maximum rated temperature of the motor. One method can include pulsing power to the motor for a second time interval after a first time interval has elapsed and tailoring pulse shapes of the power provided to the motor for the second time interval. One method can include calculating a maximum phase current based on the rotor shaft torque for each real-time speed of the motor that correlates to the maximum allowable current draw from the power supply.
Abstract:
Embodiments of the invention provide a fire-extinguishing system for injecting foamant into a stream of water. The system can include a flow meter determining a flow rate of the stream of water and a foam pump having an inlet coupled to a supply of foamant and an outlet coupled to the stream of water. The system includes a servo motor driving the foam pump. The servo motor includes a sensor used to determine a rotor shaft speed and/or a rotor shaft torque. A controller can control an operating speed of the servo motor using closed-loop control depending on the How rate and the rotor shaft speed and/or the rotor shaft torque.
Abstract:
The invention provides a variable speed hydraulic pump designed to operate at a maximum horsepower throughout its pressure range by adjusting motor speed according to motor load parameters. In particular, the variable speed hydraulic pump includes a hydraulic pump unit coupled to a variable speed electric motor by a drive unit and to a hydraulic fluid tank for pressurizing and pumping hydraulic fluid when operated by the motor. A motor controller is electrically connected to the motor to supply drive signals to the motor based on electrical characteristics of the drive signals which are dependent on the load exerted on the motor. Suction from the load is provided by both the main pump and a bidirectional supercharging pump by reversing the direction of the motor and shifting a 4/3 valve to connect the main pump inlet to the load and its outlet to tank. In addition, the controller reduces the motor speed at the maximum rated pressure to just maintain the pressure, to reduce the amount of fluid pumped through the maximum pressure relief valve.