초록 ▼

A small sized electro-optic voltage sensor capable of accurate measurement of high voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation. A polarization beam displacer

A small sized electro-optic voltage sensor capable of accurate measurement of high voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation. A polarization beam displacer separates the input beam into two beams with orthogonal linear polarizations and causes one linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels effect elliptically polarizes the beam as it travels through the crystal. A reflector redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization. The system may include a detector for converting the output beams into electrical signals and a signal processor for determining the voltage based on an analysis of the output beams.

대표청구항 ▼

A small sized electro-optic voltage sensor capable of accurate measurement of high voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation. A polarization beam displacer

A small sized electro-optic voltage sensor capable of accurate measurement of high voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation. A polarization beam displacer separates the input beam into two beams with orthogonal linear polarizations and causes one linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels effect elliptically polarizes the beam as it travels through the crystal. A reflector redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization. The system may include a detector for converting the output beams into electrical signals and a signal processor for determining the voltage based on an analysis of the output beams. of claim 2, wherein the resistive network control circuit selectively alters the resistive network in a timing fashion to cause the first pre-determined current to flow through the series combination of the semiconductor switch and the resistive network during the startup period and to cause the second pre-determined current to flow through the series combination of the switch and the resistive network during the steady-state period. 6. The ballast circuit of claim 1, the power factor correction circuit further comprising: a power factor controller with an input lead and an output lead; a first semiconductor switch with a control lead operationally coupled to the output lead of the power factor controller; a first resistor with a first lead operationally coupled to an output lead of the first semiconductor switch and a second lead operationally coupled to the return line; a first impedance device with a first lead operationally coupled to the input lead of the power factor controller and a second lead operationally coupled to the output lead of the first semiconductor switch and the first lead of the first resistor; a second impedance device with a first lead operationally coupled to the input lead of the power factor controller and the first lead of the first impedance device; a second semiconductor switch with an input lead operationally coupled to a second lead of the second impedance device and an output lead operationally coupled to the return line; a d.c. voltage source with a negative lead operationally coupled to the return line; a capacitor with a first lead operationally coupled to a positive lead of the d.c. voltage source and a second lead operationally coupled to a control lead of the second semiconductor switch; and a second resistor with a first lead operationally coupled to the second lead of the capacitor and the control lead of the second semiconductor switch and a second lead operationally coupled to the return line. 7. The ballast circuit of claim 6, wherein an input lead of the first semiconductor switch is for receiving a d.c. voltage signal and the output lead of the first semiconductor switch is for transmitting the d.c. voltage signal to subsequent components of the power factor correction circuit. 8. The ballast circuit of claim 6, the power factor correction circuit further comprising: an inductor with a first lead for receiving a d.c. voltage signal; a diode with a first lead operationally coupled to a second lead of the inductor and a second lead for providing the d.c. bus to subsequent components of the ballast circuit; and wherein the first semiconductor switch includes an input lead operationally coupled to the second lead of the inductor and the first lead of the diode. 9. A power factor correction circuit for a ballast circuit, the power factor correction circuit comprising: a power factor controller with an input signal and an output signal; a semiconductor switch operationally coupled to the output signal of the power factor controller; a selectively alterable impedance network operationally coupled to an output of the semiconductor switch and operationally coupled to the input signal of the power factor controller; and an impedance network control circuit operationally coupled to the impedance network, wherein the impedance network control circuit selectively alters the impedance network in a timing fashion to cause a first pre-determined current to flow through the series combination of the switch and the impedance network during a startup period and to cause a second pre-determined current to flow through the series combination of the switch and the impedance network during a steady-state period. 10. The power factor correction circuit of claim 9, wherein the power factor controller controls the semiconductor switch in an on/off fashion using the output signal. 11. The power factor correction circuit of claim 9, wherein the selectively alterable impedance net