2-27
D Surge Killers
Install
surge killers for loads
that have induction coils, such as relays, solenoids, brakes, clutches, etc.
The following table shows types of surge killers and recommended products.
Type Features Recommended products
Diode Diodes are relatively small devices such as relays used
for loads when reset time is not an issue. The reset time
is increased because the surge voltage is the lowest
when power is cut off. Used for 24/48-VDC systems.
Use a fast-recovery diode with a
short reverse recovery time.
Fuji Electric Co., ERB44-06 or equiv-
alent
Thyristor
or
Varistor
Thyristor and varistor are used for loads when induction
coils are large, as in electromagnetic brakes, solenoids,
etc., and when reset time is an issue. The surge voltage
when power is cut off is approximately 1.5 times that of
the varistor.
Select varistor voltage as follows:
24-VDC system varistor: 39 V
100-VDC system varistor: 200 V
100-VAC system varistor: 270 V
200-VAC system varistor: 470 V
Capacitor
+ resistor
Use capacitors and resistors for vibration absorption of
surge when power is cut off. The reset time can be
shortened by proper selection of the capacitor or resis-
tor.
Okaya Electric Ind.
CR-50500 0.5 µF-50 Ω
CRE-50500 0.5 µF-50 Ω
S2-A-0 0.2 µF-500 Ω
Note Thyristors
and varistors are made by the following companies. Refer to manufacturers documentation for
operating details. Thyristors: Ishizuka Electronics Co.
Varistors: Ishizuka Electronics Co., Matsushita Electric Parts
D Contactors
When
selecting contactors, take into consideration the circuit’
s inrush current and the momentary
maxi
-
mum
current. The Servo Driver inrush current is 50 A, and the momentary maximum current is approxi
-
mately twice the rated current. The following table shows the recommended contactors.
Maker Model Rated current Momentary maxi-
mum current
Coil voltage
OMRON
G6C-2BND 10 A --- 24 VDC
LY2-D 10 A --- 24 VDC
G7L-2A-BUBJ 25 A --- 24 VDC, 200 to 240 VAC
J7AN-E3 15 A 120 A 24 VDC
LC1-D093A60 1
1 A
200 A 24 VDC, 200/220 VAC,
200 to 240 VAC
D Leakage Breakers
Select
leakage breakers designed for inverters. Since switching operations take place inside the Servo
Driver
, high-frequency current leaks from the armature of the Servomotor
. With inverter leakage break
-
ers,
high-frequency current is not detected, preventing the breaker from operating due to leakage cur
-
rent.
Another way to prevent leakage current from being detected is to install an insulating transformer
.
When
selecting leakage breakers, remember to also add the leakage current from devices other than
the
Servomotor
, such as machines using a switching power supply
, noise
filters, inverters, and so on.
The following table shows the Servomotor leakage currents for each Servo Driver.
Driver Leakage current (direct)
(including high-frequency current)
Leakage current (resistor-capaci-
tor, in commercial power supply
frequency range)
R88D-UEP04H to -UEP08H 80 mA 3 mA
R88D-UEP12H 60 mA 4 mA
R88D-UEP20H 110 mA 5 mA
System Design and Installation
Chapter
2
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