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6 Specifications of Peripheral Devices
MITSUBISHI CNC
6 - 8
6-2 Selection of circuit protector and contactor
Always select the circuit protector and contactor properly, and install them to each power supply unit to prevent
disasters.
6-2-1 Selection of circuit protector
Calculate a circuit protector selection current from the rated output and the nominal input voltage (voltage
supplied to the power supply unit) as in the expression below. And then select the minimum capacity circuit
protector whose rated current meets the circuit protector selection current.
< MDS-D Series >
Circuit protector selection current [A] =
(Circuit protector selection current for 200V input [A] / Nominal input voltage [V]) × 200 [V]
Selection of circuit protector for 200V input
Option part: A circuit protector is not prepared as an NC unit accessory, so purchase the part from your
dealer, etc.
< MDS-DH Series >
Circuit protector selection current [A] =
(Circuit protector selection current for 380V input [A] / Nominal input voltage [V]) × 380 [V]
Selection of circuit protector for 380V input
Option part: A circuit protector is not prepared as an NC unit accessory, so purchase the part from your
dealer, etc.
Unit type
MDS-D-CV-
37 75 110 185 300 370 450 550
Rated output 3.7kW 7.5kW 11kW 18.5kW 30kW 37kW 45kW 55kW
Circuit protector selection
current for 200V input
15A 31A 45A 76A 124A 153A 186A 224A
Selection example of circuit protector
(Mitsubishi Electric Corp.)
NF63-
CW3P-
20A
NF63-
CW3P-
40A
NF63-
CW3P-
50A
NF125-
CW3P-
100A
NF250-
CW3P-
125A
NF250-
CW3P-
175A
NF250-
CW3P-
200A
NF250-
CW3P-
225A
Rated current of the selection example
of circuit protector
20A 40A 50A 100A 125A 175A 200A 225A
(Example)
Select a circuit protector for using the MDS-D-CV-110 with a 220V nominal input voltage.
Circuit protector selection current = 45/220 × 200 = 40.9[A]
According to the table above, select "NF63-CW3P-50A".
Unit type
MDS-DH-CV-
37 75 110 185 300 370 450 550 750
Rated output 3.7kW 7.5kW 11kW 18.5kW 30kW 37kW 45kW 55kW 75kW
Circuit protector selection current for
380V input
8A 16A 24A 40A 65A 80A 98A 119A 163A
Selection example of circuit protector
(Mitsubishi Electric Corp.)
NF63-
CW3P-
10A
NF63-
CW3P-
20A
NF63-
CW3P-
30A
NF63-
CW3P-
40A
NF125-
CW3P-
75A
NF125-
CW3P-
100A
NF125-
CW3P-
100A
NF250-
CW3P-
125A
NF250-
CW3P-
200A
Rated current of the selection example
of circuit protector
10A 20A 30A 40A 75A 100A 100A 125A 200A
(Example)
Select a circuit protector for using the MDS-DH-CV-450 with a 480V nominal input voltage.
Circuit protector selection current = 98/480×380 = 77.6[A]
According to the table above, select "NF125-CW3P-100A".
1. It is dangerous to share a circuit protector for multiple power supply units, so do not share it.
Always install the circuit protectors for each power supply unit.
2. If the control power (L11, L21) must be protected, select according to the section "6-4-1 Circuit
protector ".
CAUTION