2-22 Installation
P/N 0013-1027-005 Rev A
If EMI problems persist, additional counter measures can be attempted. Several suggestions for
systems modifications follow.
1. A ferrite “doughnut” or torroid around a signal cable may help. The ferrite will attenu-
ate common mode noise but will do nothing for differential mode noise. Specifically,
this should help RS232 communication problems.
2. Suppress each switched inductive device that is near the servo amplifier. This includes
solenoids, relay coils, starter coils and AC motors (such as in motor driven mechanical
timers).
3. DC coils should be suppressed with a ‘free-wheeling’ diode connected across the coil
4. AC coils should be suppressed with RC filters (a 200 ohm 1/2 Watt resistor in series
with a 1/2 microFarad, 600 Volt capacitor is commonly used).
5. Motor Power Windings can be grounded, shielded, and choked to minimize noise emis-
sions.
FIGURE 2.16 Torroid Encoder Shielding Method for Brushless Servo Motors
FIGURE 2.17 Motor Power Winding Methods to Minimize Noise Emissions
AMPLIFIER
SHIELD
ENCODER CABLE
MOTOR CASE
BRUSHLESS
MOTOR
Belden Part No. Carol Part No.
Recommended raw cable for
building your own cable
C06258337
Elec-
IQ 2000/
AMPLIFIER
SHIELD
TWISTED TOGETHER
MOTOR CASE
BRUSHLESS
MOTOR
T
S
R
CHASSIS
T
S
R
TO SINGLE POINT
EARTH GROUND
AMPLIFIER
TWISTED TOGETHER
MOTOR CASE
BRUSHLESS
MOTOR
T
S
R
CHASSIS
T
S
R
TO SINGLE POINT
EARTH GROUND
AMPLIFIER
TWISTED TOGETHER
MOTOR CASE
BRUSHLESS
MOTOR
T
S
R
CHASSIS
T
S
R
TO SINGLE POINT
EARTH GROUND
COMMON MODE CHOKE
(10-20 TURNS ON COMMON
FERRITE TOROIDOL CORE)
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