Esterline

Other

Glenn A Mayfield

A watt/watthour meter of improved accuracy and relatively lower cost than a conventionally designed device with similar specifications. A current proportional to instantaneous power is obtained from a current-voltage multiplier circuit and is maintained as a current signal through amplifying and filtering, and through the watt output load. The watt output amplifier is a current input, current output amplifier which simultaneously functions as an active ripple filter. It directly couples the input signal to the inverting input and capacitively couples the input ripple to the non-inverting input of the amplifier's op-amp. The output load, which is externally connected between the inverting input and the output of the op-amp, does not have a common with the internal ground and effectively floats with the ripple.

Watt/watthour transducer and amplifier-filter therefor

A watt/watthour meter of improved accuracy and relatively lower cost than a conventionally designed device with similar specifications. A current proportional to instantaneous power is obtained from a current-voltage multiplier circuit and is maintained as a current signal through amplifying and filtering, through the watt output load and through integrating in the watthour section. The multiplier uses a chopper modulator which provides two identical output current sources both floating with respect to ground so that one may be connected to the watt output amplifier and one to the watthour integrator. The signal from the power line which is proportional to the voltage modulates the signal which is proportional to the power line current by alternatively switching the modulated current between the two source outputs and by maintaining zero average input current flow from the modulated current signal through use of dc blocking capacitors.

Watt/watt hour transducer having current signals and a modulator therefor

A watt/watthour meter of improved accuracy and relatively lower cost than a conventionally designed device with smilar specifications. A current proportional to instantaneous power is obtained from a current-voltage multiplier circuit and is maintained as a current signal through amplifying and filtering and through the watt output load and through integrating in the watthour section. The watthour integrator uses a charge compensation integrator circuit to integrate one of the watt signal currents and it can integrate in either direction corresponding to power in or power out. This can be accomplished because circuitry is disclosed to provide a current pulse having a precise magnitude and in either of two alternative, opposite current flow directions. The magnitude of the current pulse in both directions is referenced from the same reference voltage and reference resistance and its duration is referenced from the same timer so that an identical quantum of charge may be either added to or removed from the integrator depending upon the direction of power flow.

Watt/watthour transducer and integrator and current sources therefor

A circuit for providing an output direct current which is a linearly proportional analog of the average and the effective magnitude of a sinusoidal input voltage or current. A transformer couples the sinusoid to a rectifier which applies a rectified sinusoid to a filtered current mirror circuit of low power requirements in order to provide a ripple free, high impedance current source output. The current mirror circuit is imbalanced in order to provide a non-linear characteristic which compensates for the transformer-rectifier non-linearity. The current mirror circuit also has an RC feedback network with sufficient feedback and gain to obtain an active, low pass filter characteristic. Component values are selected to give a sharp cutoff, active filter just below the ripple frequency to give efficient ripple elimination yet permit a rapid response time. Matched, parallel connected semiconductor devices in the current mirror circuit permit circuit balance with the current in one branch being an integral multiple of current in the other branch.

Growing community of inventors

Columbus, OH, United States of America

Glenn A Mayfield