
B–65162E/03
G. SERVO AMPLIFIER NOISE
PROTECTION
APPENDIX
631
(5) FAX
<<Symptoms>>
When the machine is operated, e telephone within the plant picks up
noise, or a facsimile machine of a neighboring firm is disabled. The
telephone within the plant uses 100 V; when the 100–V supply is
removed, normal telephone communications are resumed.
<<Possible causes>>
The transformer of a utility pole is shared, so that conductive noise
is conveyed through the power line. Or, noise may be induced in the
wiring as in the case of (4) above.
<<Measures>>
1 Feed power to the neighbors from a separate utility pole.
2 Install an insulating transformer (noise cut transformer) in the
power supply.
<<Notes>>
D As with (4) above, a noise filter (LC filter) may have no effect on
low–frequency noise.
As mentioned above, the protective measures and devices depend on the
types of noise, noise sources, and the level of the noise. Noise–preventive
devices are outlined below. The user should apply measures that are
appropriate for the situation. For details including the specifications of
these devices, contact the corresponding manufacturer. The contact for
each manufacturer is listed below.
Okaya Electric Industries : Sales Division 03(3424)8126
Soshin Electric : EMC Division 03(3775)9112
TDK : Electronic Device Division 03(5201)7229
Tokin : Sales Promotion Division 03(3475)6818
Fuji Electric : Sales Group, Device Division 03(3211)9288
(1) Noise Filter
A noise filter is installed between a power supply and servo amplifier to
reduce high–frequency noise superimposed on supply voltage (noise
terminal voltage). A noise filter is useful for the AM radio frequency
band.
Example products:
Okaya Electric : 3SUP–H/3SUP–D series
Soshin Electric : NF3000/HF3000 series
TDK : ZRCT/ZRGT series
Tokin : LH–3/LH–4 series
(2) Capacitor
A capacitor is directly connected to a servo amplifier to reduce radiation
noise from the power line. When compared with a noise filter, a capacitor
offers poorer attenuation characteristics, but is often more effective,
depending on the electromagnetic wave status. Considering the leakage
current, select a ground fault interrupter.
G.3.4
Noise–preventive
Devices