Mitsubishi Electric NF250-HEV, Instruction Manual

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6. MDU Detailed Specifications
6.1 Precautions for measurement
(1) Electric current measurement accuracy
The MDU electric current measurement accuracy is ± 1.0% of the maximum current setting (measurement rated current) of the circuit breaker.
For example, the permissible difference of NF400-SEW with MDU is 4.0 A (400 A × 1.0%), so the permissible difference from a current of 0 A to
400 A would be ± 4.0 A.
If the measurement value is less than 1.0%, the display value is cut off to 0 A. However, if the current is 0.4% or more of the rated value, the electric power
and electric energy are measured.
Measurement value
4.0 A
4.0 A
4.0 A
Permissible
error range
0 A 400 A Input value
to
(time limit)
t (Time)
Io
0.95 I
I
(2) Demand value
The demand value is generally the average value over the demand time limit.
The demand time limit (to) is the time until the measurement display value (lo) when a fixed input (I) is continuously powered displays 95% of the input (I).
It will take an amount of time roughly equal to three times the time limit (to) to display 100% of the input (I).
(3) Power factor measurement accuracy
The MDU power factor measurement accuracy is 5% versus the 90° electric angle.
This is phase angle 4.5
° . With regard to power factor this means that a display value up to around 0.3% (LEAD (forward) 99.7 to LAG
(delay) 99.7) at 100% and around 6% (64.9 to 76.0) at 70.7% of LEAD or LAG will be allowed.
Measurement
display value
45 ° -45 ° 0 °
Power
factor
-99.7%
100%
+99.7%
Permissible error range
-70.7%
76.0%
70.7%
64.9%
± 4.5 °
± 4.5
°
± 5%
of 90 °
Permissible error range
Forward (LEAD) Delay (LAG)