| 摘要 |
<p>This invention relates to a circuit for the protection of a dynamoelectric machine. The device is particularly directed to the protection of a rotor from thermal overloads. The circuit basically produces two signals; proportional to the positive sequence currents flowing in the rotor and the second proportional to the negative sequence currents flowing in the rotor. These two signals are injected into solid state logic circuitry such that each signal is squared; the negative sequence signal multiplied by a proportionality constant; and the two signals are then summed and fed into a thermal analog device which provides an indication of the rotor temperature at any particular interval of time. A level detector is supplied to the thermal analog device to sense the signal corresponding to the temperature of the rotor in the thermal analog device and when this signal is of a predetermined magnitude, corrective action may be taken to shut down or unload the dynamoelectric machine.</p> |
