G VA Check Screen
VA Check Screen
Press Gat any time to access the VA Check screen, which displays volts graphed against amps. P ess Ga second time to exit the VA Check screen and return to your sta ting point.
provide a meaningfulfordisplay. If the Tester is set for manual ranging (MAN), both scales (ranges) a e fixed; you may have to choose AUTO (press rfor 1 second) or select an app opriate manual range in either V or A, or both
With the VA Check sc een, the Tester displays one cycle of the fundamental frequency (current on the vertical scale, voltage on the horizontal scale). The resulting graph can appear as a straight line, a stepped line, an ellipsoid, or as some other pattern that you would normally expect to see on an oscilloscope with two input channels.
Use the VA Check sc een to show the phase shift of the fundamental frequency and detect the existence and severity of nonlinearity caused by harmonics. It could be that the VA Check screen may simply show that you
have clamped the Cu | ent Probe in the wrong direction. Figure 15 shows |
some typical VA Check signatures. | |
When the Tester is set | autoranging (AUTO), ranges for the vertical and |
horizontal scales on the VA Check screen are adjusted automatically to | |
functions (i.e., press briefly for each range change).
Note
V or A ranges cannot be changed while in the VA Check screen.
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