Lightning Surge Protection Countermeasure - Mitsubishi M80 series Connection And Set Up Manual

M800S/M80 Series Connection and Setup Manual
5 Installation

5.2.4 Lightning Surge Protection Countermeasure

Generally, the lightning surge intrudes into the control power supply of device from the power supply line, and the surge
may damage the control power supply and the internal circuit.
For protection from the lightning surge, MITSUBUSHI NC unit has the surge absorber for the control power supply of the
NC control section and the NC drive section.
However, when there is a device which is not applied with the countermeasure as illustrated below, the lightning surge
may intrude through the signal line of the device which is not applied with the countermeasure and may damage the NC
device.
Power supply line
(1) Protection countermeasure method
Add the surge absorber to the power supply lines as illustrated below for the power supply device, etc., which are
separately prepared.
The following two items are needed to protect the whole from surge.
- Surge absorber installation
- Circuit protector installation
Power supply line
Circuit protector
(2) Product example of surge absorber
Case of OKAYA ELECTRIC INDUSTRIES surge absorber
Rated Voltage
Type
(50/60Hz)
250VAC
RSPD-250-U4
(Three phase)
(Note) Refer to "EMC Installation Guidelines: EMC Countermeasure Parts: Surge Absorber" for the outline, etc.
Refer to the manufacturer catalog for detailed characteristics, outline and connection methods of the
surge absorber.
IB-1501269-F
NC control section
NC drive section
(Servo/spindle
drive unit)
Lightning surge path
Panel
power supply
Path of damage caused by lightning surge
Surge absorber
Lightning surge countermeasure for three-phase power supply line
DC Breakdown Voltage
voltage protection level
700V±25% 1.3kV
156
Control panel
(relay panel, etc.)
Other device
(panel power
supply, etc.)
Normal discharge Max. discharge
current current
8/20μs 8/20μs
2.5kA 5kA
Control panel
(relay panel, etc.)
Surge current life
Approx. 300 times
8/20μs-1kA