Appendix B. V Disturbance/V Output Feature - AEMC 5070 User Manual

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APPENDIX B. V DISTURBANCE/V OUTPUT FEATURE

The V Disturbance/V Output feature (referred to in the text of this manual as dlSt)
serves two purposes.
First it acts as a safety device inhibiting the instrument from generating a test
voltage when live signals are present.
In the SET-UP mode, you can choose a percentage of the test voltage that
constitutes a condition that requires the test to be inhibited before it starts. If the
Model 5070 measures a voltage higher than the V Disturbance/V Output setting
allows, no test voltage will be generated when the Start button is pressed.
The calculation for this condition is simple. In the set up mode, you have a choice
to set the ratio for V Disturbance/V Output (stated as dlSt) to 3, 10 or 20%. The
inhibit voltage is then calculated by multiplying this percentage times the test
voltage.
Test voltage is set to 500 and the V Disturbance/V Output is set to
3% therefore the voltage present at the input terminals before the start of a test
that will inhibit testing is (500)(0.03) = 15 V. The table below shows the inhibit
Output percentages.
Test
Voltage
500
1000
2500
5000
If a sudden change in voltage occurs during the test, the formula for calculating
500 V as the test voltage and 3% as dlSt, the inhibit voltage that must occur after
a test is started is (500)(1.05 + .03) = 540 volts. The table below shows the inhibit
Output percentages that must occur after a test starts.
Test
Voltage
500
1000
2500
5000
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3% 10% 20%
15 50 100
30 100 200
75 250 500
150 500 1000
3% 10% 20%
540 575 625
1080 1150 1250
2700 2875 3125
5400 5750 6250
Megohmmeter Model 5070
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