SURFACE POTENTIAL DISTRIBUTION MEASURING DEVICE AND SURFACE POTENTIAL DISTRIBUTION MEASURING METHOD

摘要

In a surface potential distribution measuring device for an electric field reduction system of a rotating electrical machine, a Pockels crystal is used between a laser and the surface (test location) of the electric field reduction system. Thus, the light Light intensity of a laser beam reflected on a mirror provided between the Pockels crystal and the test location corresponds to an output voltage that is the voltage difference between the first end surface and the second end surface of the Pockels crystal. Even when an inverter voltage is generated, by using a light detector having a frequency band capable of following the high frequency components of the inverter pulse voltage, the light intensity is detected by the light detector. Therefore, from the light intensity (output voltage), the surface potential distribution measuring device can measure the surface potential of the electric field reduction system in which an inverter pulse voltage is generated.

主权项

1. A surface potential distribution measuring device that measures a surface potential of at least one electric field reduction system applied to a stator coil end which is an end portion of a stator coil of a rotating electrical machine, the device comprising:
a laser configured to emit laser light; a Pockels crystal configured to receive, at its first end surface, the laser light emitted from the laser; a mirror having a mirror surface at a second end surface of the Pockels crystal and configured to reflect the laser light incident from the first end surface of the Pockels crystal in a direction opposite to an incident direction of the laser light; a light detector having a band following a high-frequency component of an inverter pulse voltage and configured to receive the laser light reflected by the mirror and detecting, as a light intensity of the laser light, a detection light intensity corresponding to an output voltage which is a potential difference between the first end surface of the Pockels crystal and the second end surface thereof; a voltage calibration database configured to store, when a plurality of mutually different input voltages are applied to a rear surface of the mirror in voltage calibration processing to be performed before a test, input-to-output voltage characteristics representing a relationship between the different input voltages and the output voltages of the Pockels crystal obtained when the different input voltages are applied to the rear surface of the mirror; and a computing section configured to set, when a part of a surface of the electric field reduction system is set at a rear side of the mirror as a test location in surface potential measurement processing to be performed during the test, the output voltage of the Pockels crystal obtained when a voltage is applied to the stator coil as an output voltage at test time and identifying an input voltage corresponding to the output voltage at test time as the surface potential of the electric field reduction system based on the input-to-output voltage characteristics stored in the voltage calibration database.