Mitsubishi Electric MR-J5D User Manual page 130

Noise transmission
route
(1), (2), (3)
(4), (5), (6)
(7)
(8)
6 OPTIONS AND PERIPHERAL EQUIPMENT
128
6.6 Noise reduction techniques
Suppression techniques
A malfunction due to noise transmitted through the air may occur in devices which handle weak signals and are susceptible to
noise, such as measuring instruments, receivers and sensors. In addition, a malfunction may also occur when their signal
cables are stored in a cabinet together with the converter unit/drive unit or when the signal cables run near the converter unit/
drive unit. Take the following measures to prevent a malfunction:
• Provide maximum clearance between easily affected devices and the converter unit/drive unit.
• Provide maximum clearance between easily affected signal cables and the I/O cables of the converter unit/drive unit.
• Avoid bundling power lines (input/output lines of the converter unit/drive unit) and signal cables together or running them in
parallel to each other.
• Insert a line noise filter to the I/O cables or a radio noise filter on the input line to reduce radiated noise from the cables.
• Use shielded wires for the signal and power lines, or put the lines in separate metal conduits.
When power cables and signal cables are laid side by side or bundled together, electromagnetic and static induction noise is
transmitted to the signal cables, causing malfunctions. Take the following precautions to protect the signal cables against
noise.
• Provide maximum clearance between easily affected devices and the converter unit/drive unit.
• Provide maximum clearance between easily affected signal cables and the I/O cables of the converter unit/drive unit.
• Avoid bundling power lines (input/output lines of the converter unit/drive unit) and signal cables together or running them in
parallel to each other.
• Use shielded wires for the signal and power lines, or put the lines in separate metal conduits.
When the power supply of peripheral equipment is connected to the power supply of the converter unit/drive unit system, noise
produced by the converter unit/drive unit may be transmitted back through the power supply cable, and the equipment may
malfunction. The following techniques are required.
• Install the radio noise filter (FR-BIF(-H)) on the power lines (input lines) of the converter unit/drive unit.
• Install the line noise filter (FR-BLF) on the power lines of the converter unit/drive unit.
If the grounding wires of the peripheral equipment and the converter unit/drive unit make a closed loop circuit, leakage current
may flow through, causing the equipment to malfunction. In this case, the malfunction may be prevented by disconnecting the
grounding wires from the equipment.