4 selecting cable, Installation – MMD Equipment 150S-6A6 User Manual

Page 25

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3. Installation

3-9

3.4 Selecting Cable

Select a cable with sufficient diameter by considering the permissible current on the cable and the
distance from the generator to the load.

If the current flowing to the load exceeds the permissible current of the cable, resultant
overheating may burn the cable. Similarly, if the cable is too small in thickness to the length, the
input voltage to the load will fall to cause the load input power to drop, as a result, the performance
of the machine cannot be displayed.

Simplified three-phase three-wire formula to seek voltage drop from cable length and working

current. Select such a cable length and thickness so that the voltage drop will remain less
than 5%.

Output system

Voltage drop

Three-phase 3-wire Type

Three-phase 4-wire Type

The following tables show the relations between the cabtyre cable length and the cable thickness

(nominal cross-sectional area) suited to the working current.

(Based on the condition that working voltage is 200 V, with voltage drop of 10V.)

Single-Conductor Cabtyre Cable Unit:mm

2






Three-Conductor Cabtyre Cable Unit:mm

2



50m 75m 100m 125m 150m 200m

50A 8 14 22 22 30 38

100A

22 30 38 50 50 60

150A

38 38 50 60 80 100

50m 75m 100m 125m 150m 200m

50A 14 14 22 22 30 38

100A

38 38 38 50 50 60

150A

22×2 22×2 38×2 38×2 38×2 50×2

Cable Length L(m)

Length

Current

Current

A040657

Length

Cable Thickness A (mm

2

)

Working

Current I (A)

e

:

Voltage drop(V)

e

:

Voltage drop between an outside

line or one line of each phase,
and a neutral line (V)

A

Cable thickness (mm

2

)

L

Cable length (m)

I

Working current (A)

e = 1,000×A

e =

17.8×L×I

1,000×A

30.8×L×I

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