Hitachi SJ300-037HFE 사용자 설명서

Maintenance and Inspection

T

roub

leshooting

and Maintenance

The figure below shows measurement locations for voltage, current, and power measurements 
listed in the table on the previous page. The voltage to be measured is the fundamental wave 
effective voltage. The power to be measured is the total effective power.

Taking voltage measurements around drives equipment requires the right equipment and a safe 
approach. You are working with high voltages and high-frequency switching waveforms that 
are not pure sinusoids. Digital voltmeters will not usually produce reliable readings for these 
waveforms. And, it is usually risky to connect high voltage signals to oscilloscopes. The 
inverter output semiconductors have some leakage, and no-load measurements produce 
misleading results. So, we highly recommend using the following circuits to measure voltage 
for performing the equipment inspections.

HIGH VOLTAGE: Be careful not to touch wiring or connector terminals when working with 
the inverters and taking measurements. Be sure to place the measurement circuitry above in an 
insulated housing before using them.

E

1

I

1

I

1

I

1

I

1

E

U-V

E

U-V

E

U-V

W

01

W

02

W

01

W

02

E

1

E

1

I

2

I

3

L1

L2

L3

T1

T2

T3

R

S

T

U

V

W

V/T2

W/T3

U/T1

L2/S

L3/T

L1/R

V/T2

W/T3

U/T1

L2/S

L3/T

L1/R

V class

Diode bridge

Voltmeter

200V class

600V 0.01A min.

300V range

400V class

1000V 0.1 A min.

600V range

220k

Ω

+

–

220k

Ω

+

–

Voltage measurement with load

Inverter

Voltage measurement without load

Inverter

V class

Diode bridge

Voltmeter

200V class

600V 0.01A min.

300V range

400V class

1000V 0.1 A min. 600V range

5k

Ω