Omron OMNUC G User Manual page 219

Surge Suppressors
Install surge suppressors for loads that have induction coils, such as relays, solenoids, brakes,
clutches, etc.
The following table shows the types of surge suppressors and recommended products.
Type
Diodes are used for relatively small loads
when the reset time is not an issue, such
as relays.
Diode
At power shutoff the surge voltage is the
lowest, but the reset time takes longer.
Used for 24/48-VDC systems.
Thyristors and varistors are used for loads
with large induction coils, as in electro-
Thyristor or magnetic brakes, solenoids, etc., and
varistor when reset time is an issue. The surge
voltage at power shutoff is approximately
1.5 times the varistor voltage.
The capacitor plus resistor combination is
used to absorb vibration in the surge at
Capacitor
power shutoff. The reset time can be
+ resistor
shortened by selecting the appropriate ca-
pacitance and resistance.
Thyristors and varistors are made by the following companies. Refer to manufacturers'
documentation for details on these components.
Thyristors: Ishizuka Electronics Co.
Varistors: Ishizuka Electronics Co., Matsushita Electric Industrial Co.
Contactors
Select contactors based on the circuit's inrush current and the maximum momentary phase
current.
The Servo Drive inrush current is covered in the preceding explanation of no-fuse breaker
selection, and the maximum momentary phase current is approximately twice the rated current.
The following table shows the recommended contactors.
Manufacturer
J7L-09-22200
J7L-12-22200
J7L-18-22200
J7L-32-22200
OMRON
J7L-40-22200
J7L-50-22200
J7L-65-22200
J7L-75-22200
4-3 Wiring Conforming to EMC Directives
Features
Model Rated current
Recommended products
Use a fast-recovery diode with a short re-
verse recovery time (e.g. RU2 of Sanken
Electric Co., Ltd.).
Select the varistor voltage as follows:
24 VDC system: Varistor V. 39V
100 VDC system: Varistor V. 200 V
100 VAC system: Varistor V. 270 V
200 VAC system: Varistor V. 470 V
Okaya Electric Industries Co., Ltd.
XEB12002 0.2 μF - 120 Ω
XEB12003 0.3 μF - 120 Ω
Coil voltage
11 A 200 VAC
13 A 200 VAC
18 A 200 VAC
26 A 200 VAC
35 A 200 VAC
50 A 200 VAC
65 A 200 VAC
75 A 200 VAC
4
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