9 - 14
9.1 Requirements for Conformance to EMC Directive
9.1.6 Others
9
EMC AND LOW VOLTAGE DIRECTIVES
(3) Isolation transformer
An isolation transformer has an effect on reducing conducted noise (especially,
lightning surge).
Lightning surge may cause a malfunction of the programmable controller.
As a measure against lightning surge, connect an isolation transformer as shown in
Diagram 9.20.
The use of an isolation transformer reduces an impact of lightning.
Table9.6 lists the recommended isolation transformers.
Diagram 9.20 Power supply wiring diagram
Table9.6 Isolation transformer
Model 4H503-092 4H400-104 4H503-093
Specifications
Rated capacity: 200VA
Isolation type: A
Frequency: 50/60Hz
Input: 200V/100VAC
Output: 200/100VAC
With Electrostatic shield E
Rated capacity: 200VA
Isolation type: B
Frequency: 50/60Hz
Input: 200V/100VAC
Output: 200/100VAC
With Electrostatic shield E
Rated capacity: 200VA
Isolation type: H
Frequency: 50/60Hz
Input: 200V/100VAC
Output: 200/100VAC
With Electrostatic shield E
Obtained standard None UL UL and CE
100VAC
200VAC
T1
Main
power supply
Relay
terminal block
I/O power supply
I/O equipment
Inside a control panel
Programmable
controller power
supply
Isolation
transformer
Programmable
controller
Motor power supply
Motor equipment