Measurement of voltages and currents, Protective functions, Typical measuring points and instruments – MITSUBISHI ELECTRIC FR-A500L User Manual
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PROTECTIVE FUNCTIONS
39
5.3.7 Measurement of main circuit voltages, currents and power
Measurement of voltages and currents
Since the voltages and currents on the inverter power supply and output sides include harmonics,
accurate measurement depends on the instruments used and circuits measured.
When instruments for commercial frequency are used for measurement, measure the following circuits
using the instruments given on the next page.
+
-
Ar
As
At
Vr
Vs
Vt
W
11
W
12
W
13
Au
Av
Aw
Vu
Vv
Vw
W
12
W
22
V
R 1 > S 2 > T 3 > U V W Inverter P<+> 2 <->N 5 3-phase Instrument Input voltage Input current Output voltage Output current To motor Typical Measuring Points and Instruments Note: Use an FFT to measure the output voltage accurately. Accurate measurement cannot be made if you use a tester or general measuring instruments.
power
supply
types