3-23
D
No-fuse Breakers (NFB)
When selecting no-fuse breakers, take into consideration the maximum output current and the inrush
current.
Maximum input current:
The momentary maximum output for a Servo Driver is approximately three times that of the rated out-
put, and a maximum output of three seconds can be executed. Therefore, select no-fuse breakers with
an operating time of at least five seconds at 300% of the rated maximum output. General-purpose and
low-speed no-fuse breakers are generally suitable. The table in
3-2-3 Terminal Block Wiring
shows the
rated power supply input currents for each Servomotor. Select a no-fuse-breaker with a rated current
greater than the total effective load current (when multiple Servomotors are used). When making the
selection, add in the current consumption of other controllers, and so on.
Servo Driver inrush current:
With low-speed no-fuse breakers, an inrush current 10 times the rated current flows for 0.02 second.
For a simultaneous inrush for multiple Servo Drivers, select a no-fuse-breaker with a 20-ms allowable
current greater than the total inrush current shown in the following table for the applicable Servomotor
models.
Servo Driver
Inrush current (Ao-p)
Control-circuit power supply
Main-circuit power supply
R88D-WTA3HL to -WT02HL
30
90
R88D-WTA3H to -WT04H
35
90
R88D-WT05H to -WT10H
60
130
R88D-WT15H
60
130
R88D-WT20H/-WT30H
60
140
R88D-WT50H
60
140
R88D-WT60H
65
140
D
Surge Absorbers
Use surge absorbers to absorb surges from power supply input lines due to lightning, abnormal volt-
ages, etc. When selecting surge absorbers, take into account the varistor voltage, the amount of surge
immunity, and the amount of energy resistance. The surge absorbers shown in the following table are
recommended.
Maker
Model
Varistor
voltage
Max. limit
voltage
Surge
immunity
Energy
resistance
Type
Matsushita Electric
ERZC20EK471(W)
470 V
775 V
5,000 A
150 J
Block
ERZC25EK471(W)
470 V
775 V
10,000 A
225 J
ERZC32EK471(W)
470 V
775 V
20,000 A
405 J
Ishizuka Electronics Co. Z25M471S
470 V
775 V
10,000A
235 J
Block
Z33M471S
470 V
775 V
20,000 A
385 J
Note
1.
The (W) for the Matsushita models indicates that they are UL and CSA certified.
Note
2.
Refer to the manufacturers’ documentation for operating details.
Note
3.
The surge immunity is for a standard impulse current of 8/20
µ
s. If pulses are wide, either decrease the
current or change to a larger-capacity surge absorber.
Note
4.
The energy resistance is the value for 2 ms. It may not be possible to retard high-energy pulses at less
than 700 V. In that case, absorb surges with an insulated transformer or reactor.
System Design and Installation
Chapter 3
AUDIN - 7 bis rue de Tinqueux - 51100 Reims - France - Tel : 03.26.04.20.21 - Fax : 03.26.04.28.20 - Web : http: www.audin.fr - Email : [email protected]
