
B–65162E/03
G. SERVO AMPLIFIER NOISE
PROTECTION
APPENDIX
629
Apply the most efficient measures as described in Table G.3.2
Table.G.3.2 Measures Specific to Each Type of Noise
Type of noise
Conduc- Induced Radiation
Measures
tive noise noise noise
Separation of power lines and motor power lines from
signal lines
f f
Use of metallic conduits f f
Wiring and grounding Elimination of parallel wiring f
Employing shielded wires for power lines and motor
power lines
f
Secure grounding f
Noise protective device
Line filter f f
(at noise source)
Insulating transformer f f
Noise protective device
Running signal lines through ferrite core beads f f
(on devices affected by noise)
Employing shielded wires for signal lines f f
Others Power system separation f
(1) AM Radio
<<Symptoms>>
When a motor is activated, radios in the plant pick up noise, such that
the radio output becomes inaudible.
<<Possible causes>>
Radiation noise from the motor power line connected to a servo
amplifier is being picked up by the radios.
<<Measures>>
1 Install a noise filter (LC filter) on the power supply.
2 Install a capacitor between each input phase and ground.
<<Notes>>
D The measures described above may prove ineffective in some
areas, such as dense residential areas and mountain areas, where
radio signals are weak.
D When installing a noise filter, minimize the length of the wiring
between the filter and servo amplifier.
(2) FM Radio
<<Symptoms>>
When the machine is operated, radios in the neighborhood are
affected by noise. A radio in a car parked outside the plant also picks
up noise.
G.3.3
Examples of Noise
Protection