Allen-Bradley 160-DN2, User Manual, Page: 19 / 116

Publication 0160-5.18 - June 2003
Installation and Wiring 3-3
is 220 ohms and 0.50 microfarads. Select the voltage rating for the
normal AC voltages. A typical surge suppressor that can be used for
most transient EMI problems is Electrocube part number RG1676-16
(rated 480V ac).
Surge suppressors are usually most effective when connected at the
inductive loads. However, you can also connect surge suppressors at
the switching devices, but they may be less effective because the
wires connecting the switching devices to the inductive loads act as
antennas that radiate EMI. You can evaluate the effectiveness of a
particular suppressor by using an oscilloscope to observe the voltage
waveform on the line.
Figure 3.1
Surge Suppressor Connection for 3-Phase Apparatus
Figure 3.2
Surge Suppressor Connection for Large Apparatus
Figure 3.3
Surge Suppressor Connection for Small Apparatus
Surge Suppressor
For 3-phase apparatus, a suppressor is needed across each phase
3-Phase
Motor
230/460VAC
Surge Suppressor
For large apparatus (electro-mechanical brakes, contacts up to size 5)
115/230/460VAC
Surge Suppressor
115VAC
For small apparatus (relays, solenoids, and motor starters up to size 1)