Abstract: A system for evaluating at least one tripping stimulus for a ground-fault circuit interrupter includes: a sensing circuit configured to measure a leakage current from a voltage line to ground, wherein the sensing circuit is capable of generating a leakage signal including a voltage representative of the leakage current; and an evaluating circuit configured to evaluate the leakage signal to generate an indication signal, wherein the indication signal includes information corresponding to the at least one tripping stimulus. The sensing circuit may include a circuit substantially similar to at least a portion of a ground-fault circuit interrupter, and the evaluating circuit may include a peak hold circuit. The system may further include an indicator circuit for receiving the indication signal and displaying a status of the tripping conditions.

Abstract: A system for evaluating at least one tripping stimulus for a ground-fault circuit interrupter includes: a sensing circuit configured to measure a leakage current from a voltage line to ground, wherein the sensing circuit is capable of generating a leakage signal including a voltage representative of the leakage current; and an evaluating circuit configured to evaluate the leakage signal to generate an indication signal, wherein the indication signal includes information corresponding to the at least one tripping stimulus. The sensing circuit may include a circuit substantially similar to at least a portion of a ground-fault circuit interrupter, and the evaluating circuit may include a peak hold circuit. The system may further include an indicator circuit for receiving the indication signal and displaying a status of the tripping conditions.

Abstract: A method and system for DC motor control is provided. A processor controls transistors connected to the field and armature coils of a DC motor, and measures the current and average voltage associated with said field and armature coils to determine motor speed. Motor speed is compared to a speed command to determine a speed error. The torque of the motor is adjusted to reduce the speed error. Safety features and power redistribution features are also provided.

Abstract: An apparatus and method for detecting the presence of a battery in a battery charging circuit is provided. An inductor is placed in series with a charging circuit and the battery connection leads. A switching device and a capacitive device are connected in parallel to one another and in series with a gated device to form an indicator circuit. The indicator circuit is connected in parallel with the battery connection terminals. A series of pulses is applied to the gated device, allowing current to flow into the capacitive device during each pulse and energize the switching device when a battery is present. When no battery is present, the inductor prevents sufficient current from the charging circuit from energizing the capacitive device and the switching device.

Abstract: A motor speed control system in which the rotor output frequency is filtered to remove slot noise and applied to one or more frequency discriminator units (FDU's) which provide control signals to operate relays which control contactors in a conventional motor controller having rotor speed control resistances. Each FDU compares the input frequency with its own setpoint frequency and operates to change rotor circuit resistance if the input frequency differs from the setpoint by a predetermined amount. The rotor signal is separated into two rectangular wave signals, one of which triggers a monostable circuit. The Q and Q monostable outputs are compared with the input in logic circuit means which produces a relay driving output under specified signal time-overlap conditions. A feedback signal changes the duty cycle of the monostable when the output is provided, thereby establishing a frequency "dead band" bracketing the setpoint.