Appendix C: V Disturbance/ V Output Feature - AEMC 5070 User Manual

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 mea-
sures 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.
Example: Test voltage is set to 500 and the V Disturbance/V Output is set to 3% there-
fore the voltage present at the input terminals before the start of a test that will inhibit
testing is (500)(0.03) = 15 volts. The table below shows the inhibit voltages for the 4
fixed test voltage positions and the three V Disturbance/V Output percentages.
If a sudden change in voltage occurs during the test, the formula for calculating
V Disturbance/V Output is slightly different. It is (V Output)( 1.05+ dlst). Using 500
volts 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
voltages for the 4 fixed test voltage positions and the three V Disturbance/V Output
percentages that must occur after a test starts.
90
APPENDIX C
Before Testing
Test
Voltage 3%
500 15
1000 30
2500 75
5000 150
During a Test
Test
Voltage 3%
500 540
1000 1080
2500 2700
5000 5400
V Disturbance/ V Output
10%
50
100
250
500
V Disturbance/ V Output
10%
575
1150
2875
5750
20%
100
200
500
1000
20%
625
1250
3125
6250
Megohmmeter Model 5070