Aspen Motion Technologies, Inc.

Hoffman Enclosures Inc.

Moog Gmbh

Actuant Corporation

Sta-rite Industries Inc.

Martin Piedl

Ron G Flanary

Moe K Barani

Troy Andreas Anderson

Charles Ford

George R Steber

Bruce Edwin Knuth

Robert L Hosfield

Jonathan David Gamble

Roger R Pili

Harold Mathew McCabe

Laurentius A G Mentink

Michael B Bishop

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.

Method of controlling a motor

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 flow rate and the rotor shaft speed and/or the rotor shaft torque.

Fire-extinguishing system with servo motor-driven foam pump

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.

Method of operating a motor

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.

Variable speed hydraulic pump

A method and apparatus for controlling the output function of a permanent magnet brushless DC motor ( ), by sensing an input current to the motor ( ), by computing an output torque generated by the motor ( ) as a function of the input current to the motor ( ), by computing an output pressure for a pump ( ) in response to the output torque, by reading a set point pressure, and by comparing the set point pressure to the output pressure, and in response thereto controlling on-off operation of the motor ( ). The apparatus includes a sensing circuit ( ) and a microelectronic processor ( ) for performing these functions.

Pressure control system using input current sensing

A digital signal processor for closed loop velocity or position control receives sine winding output signals and cosine winding output signal from a resolver, digitizes the signals and outputs quadrature encoded signals to an excitation circuit. The excitation circuit is connected to an excitation winding in the resolver to provide signals for driving the resolver.

Closed loop control of motor position and velocity

A resolver ( ) is provided with redundant excitation windings in which only a single excitation winding (E ) is energized externally. Cross coupling from the externally energized winding (E ) excites the other excitation winding (E ). A control circuit ( ) monitors the excitation of the redundant excitation winding (E ) and switches the excitation to the redundant excitation winding (E ) in the event of a failure of the externally winding (E ).

Low cost redundant resolver system

A resolver (10) is excited with a high frequency signal from excitation circuit (16). Outputs of the resolver (10) are transmitted through receiver circuit (24) and input to a DSP signal processing circuit (18), which demodulates the sine and cosine outputs to provide samples of the sine and cosine of the rotor position. The sample values are converted to digital values, which are used to calculate a shaft angular position, which is then used for closed loop position and velocity control of a brushless PM motor (14).

Growing community of inventors

Radford, VA, United States of America

Martin Piedl