ABB PBA2 설치 및 유지보수 지침 - 페이지 7

{카테고리_이름} ABB PBA2에 대한 설치 및 유지보수 지침을 온라인으로 검색하거나 PDF를 다운로드하세요. ABB PBA2 16 페이지. Bushing potential device

Figure 3: Connection Diagram

For this adjustment the device must be connected to its

final condenser bushing, with normal line-to-ground voltage

on the bushing stud, and with a reference voltage available

for comparison. See also ADJUSTING-GENERAL above.

The ratio or output voltage adjustment is a matter of voltage

magnitude only, and this is checked by voltmeter reading.

The phase angle of the output voltage may be checked by

low reading voltmeter, by phase angle meter or by oscilloscope,

as previously mentioned.

Fig. 4 is the circuit diagram for checking the phase angle

and ratio using the oscilloscope with vertical and horizontal

sweeps each energized at 115 volts 60 hertz. The oscilloscope

ABB

shall be adjusted so that the total deflection in each the

vertical and the horizontal directions is roughly the same.

The reference and the output voltages are in phase when

the trace on the oscilloscope is the nearest possible to a

single straight line. Some variation in the wave form of the

two voltages may prevent the trace from ever becoming a

perfect straight line. When the voltages are out of phase,

the trace tends to be an ellipse; it would be a circle with the

two voltages 90 degrees out of phase. The oscilloscope as

used here will not distinguish in-phase from 180

out-of-phase.