5.2 Measurement of main circuit voltages, currents and powers. Mitsubishi Electric Marine Battery FR-HC2, FR-HC2-7.5K, FR-HC2, FR-HC2-H7.5K

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Measurement of main circuit voltages, currents and powers

5.2 Measurement of main circuit voltages, currents and powers

 Measurement method of voltage and current at each section

When instruments for commercial frequency are used for measurement, measure the following circuits with the instruments given below.

 When installing meters etc. on the output side of the converter

When the converter-to-motor wiring length is long, especially in the 400V class, the meters may generate heat due to lineto-line leakage current. Therefore, choose the equipment which has enough allowance for the current rating.

 Voltage is output between the terminal P and N of the converter, and it can be measured using a moving-coil type meter

(tester). The voltage changes by the power supply voltage, but it decreases when a load is applied.

Outside box

Power supply

W11

W12

W13

Vu

Vv

Au

Reactor 1

Av

Aw

Filter capacitor

Limit resistor

Inrush current limit MC

Reactor 2

Converter

R4

/L14

P/+

S4

/L24

T4

/L34

N/-

V

+

To the Inverter

-

Vw

Power supply

[Examples of Measuring Points and Instruments]

Reactor 1

Outside box

Filter capacitor

Limit resistor

Inrush current limit MC

Reactor 2

Converter

R4

/L14

P/+

S4

/L24

T4

/L34

N/-

V

+

To the Inverter

-

Recommended product : YOKOGAWA251

DIGITAL POWER METER

(Voltage, current, power, and power factor can be measured.)

[Examples of Measuring Points and Instruments]

 Operation principle and application of electric meters

Type

Moving-coil type

Moving-iron meter

Ammeter type Air-core coil

Symbol Operation Principle

Uses kinetic power generated between the magnetic field of a permanent magnet and the current that flows through the moving-coil.

Command

DC

(average value)

Uses kinetic power generated between the the moving-iron and the magnetic field of the current that flows though the fixed coil.

AC

(effective value)

Uses kinetic power generated between the currents that flow through two different coils.

AC/DC

(effective value)

Applicable meter

Voltmeter/ammeter/ resistance meter/ thermometer/flux meter/speed meter

Voltmeter/ammeter

Wattmeter/ voltmeter/ammeter

Characteristic

High sensitivity and commonly used.

Energy saving, small influence of magnetic field

Strong structure and inexpensive,

Large influence from external magnetic field, frequency, and waveform

Scale is divided equally when using a wattmeter.

Large influence from external magnetic field, high energy consumption

This can be used as a standard meter for AC and DC.

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