| 摘要 |
1531382 Testing relays BBC BROWN BOVERI & CO Ltd 11 March 1977 [15 March 1976] 10492/77 Heading G1U Test apparatus for devices such as protective relays 1-3 in generating plant 39-43 provides test voltages, currents and frequencies and automatically controls the nature and the sequence of tests; the test signals being generated from an electronicallyswitched potentiometer 11 in the circuit of a secondary winding 5 of a transformer 4-6, test voltages being provided via a resistor 8, test currents via a current transformer 7, 9 and test frequencies via a voltage-to-frequency converter 14; the nature of the test being pre-set by a patch matrix 33 and. its sequence controlled by a pre-programmed controller 35. A counter 34 controls the potentiometer 11 to deliver increasing or decreasing test signals which are supplied via a voltage measuring transformer 37, 38 to a display 31 or printer 32, the counter 34 being arrested when the relay under test responds; the response time being measured by a counter 36 counting clockpulses. Since test currents may be applied while operating currents are flowing, the two currents are summed 15-19 before display. |
