Amprobe MultiTest 2000 Manual De Usuario página 160

AMPROBE
b) Resistance of an horizontal rod
L= length of the element touching the ground
c) Resistance of linked elements
The resistance of a complex system with more elements in parallel is always higher
than the resistance that could result from a simple calculation of elements in parallel,
especially if those elements are close and therefore interactive. For this reason, in
case of a linked system the following formula is quicker and more effective than the
calculation of the single horizontal and vertical elements:
r= radius of the circle which circumscribes the link.
16.5. VOLTAGE ANOMALIES (VOLTAGE SAG AND SURGE)
The Multitest 2000 is able to record as voltage anomalies all those rms values, calculated
every 10ms, beyond the percent thresholds of Voltage Reference (Vref) set during the
programming from 3% to 30 % (with step of 1%).
The Reference must be set to:
Nominal Voltage Phase to Neutral:
Nominal Voltage Phase to Phase:
Example1: Three Phase System 3 wires.
Vref = 400V, LIM+= 6%, LIM-=10% =>
High Lim = 400 x (1+6/100) = 424,0V
Low Lim = 400 x (1-10/100) = 360
Rd = 2ρ / L
Rd = ρ / 4r
for Single Phase and 4 wires three phase system
for 3 wires three phase system
Example2: Three Phase System 4 wires.
Vref = 230V, LIM+= 6%, LIM-=10% =>
High Lim = 230 x (1+6/100) = 243,08V
Low Lim = 230 x (1-10/100) = 207,0V
MULTITEST2000