Hitachi SJ300-037HFE 사용자 설명서

SJ300 Inverter

T

roub

leshooting

and Maintenance

The following table specifies how to measure key system electrical parameters. The diagrams 
on the next page show inverter-motor systems and the location of measurement points for these 
parameters.

Note 1: Use a meter indicating a fundamental wave effective value for voltage, and meters 

indicating total effective values for current and power.

Note 2: The inverter output has a distorted waveform, and harmonic frequencies may cause 

erroneous readings. However, the measuring instruments and methods listed above 
provide reasonably accurate results.

Note 3: A general-purpose digital volt meter (DVM) is not usually suitable to measure a 

distorted waveform (not pure sinusoid).

Supply voltage

E

1

E

R

 – across L1 and L2

E

S

 – across L2 and L3

E

T

 – across L3 and L1

Moving-coil type 
voltmeter or recti-
fier type voltmeter

Fundamental 
wave effective 
value

Commercial supply 
voltage (200V class) 
200-240V, 50/60 Hz
400V class 380-
460V, 50/60 Hz

Supply current

I

1

I

r

 – L1, I

s

 – L2, I

t

 – L3

Moving-coil type 
ammeter

Total effective 
value

—

Supply power W

1

W

11

 – across L1 and L2

W

12

 – across L2 and L3

Electronic type 
wattmeter

Total effective 
value

—

Supply power 

factor Pf

1

—

Output voltage 

E

0

E

U 

– across U and V

E

V 

– across V and W

E

W 

– across W and U

Rectifier type 
voltmeter

Total effective 
value

—

Output current I

o

I

U 

– U

I

V 

– V

I

W 

– W

Moving-coil type 
ammeter

Total effective 
value

—

Output power W

o

W

01

 – across U and V

W

02

 – across V and W

Electronic type 
wattmeter

Total effective 
value

—

Output power 

factor Pf

o

Calculate the output power factor from the output voltage E, output 
current I, and output power W.

—

Pf

1

W

1

3 E

1

×

I

1

×

------------------------------

100%

×

=

Pf

0

W

0

3 E

0

×

I

0

×

------------------------------

100%

×

=