Meters And Measuring Methods - Mitsubishi Electric FR-E700 Instruction Manual

Meters and measuring methods

7.7 Meters and measuring methods
NOTE For further information about measurements at the inverter refer to section 8.2.
Since voltages and currents in the primary and secondary side of the inverter include harmonics,
different meters indicate different measured values. When making measurement with the me-
ters designed for commercial frequency, use the following measuring instruments and circuits:
When installing meters etc. on the inverter output side
When the inverter-to-motor wiring length is large, especially in the 400V class, small-capacity
models, the meters and CTs may generate heat due to line-to-line leakage current. Therefore,
choose the equipment which has enough allowance for the current rating. When measuring and
indicating the output voltage and output current of the inverter, it is recommended to utilize the
AM-5 terminal output function of the inverter.
When using measuring instruments for the normal frequency range, carry out the measure-
ments as described below.
power supply
Instrument types
Fig. 7-7: Measurements at the main circuit
7 - 30
Input voltage
Input current
3-phase
Inverter
Troubleshooting
Output voltage
Output current
To the motor
Moving-iron type
Electro dynamometer type
Moving-coil type
Rectifier type
I001313E