Minimizing 50/60 Hz Line Interference - Aerotech BA10 SERIES User Manual

BA10/20/30 Series User's Manual

2.3.3. Minimizing 50/60 HZ Line Interference

Operating the BA series amplifiers from an off-line source of 115 VAC or 230 VAC
creates some additional problems.
First, there is a potential problem of EMI generated from the switching power stage of the
BA amplifier propagating through the bridge rectifier and out through the HI and LO
input AC line connections. Back-propagation of noise into the AC lines can be minimized
using a line filter. An example of such a filter and proper connection to the BA amplifier
is shown in Figure 2-5.
BA
AMPLIFIER
FRAME GROUND
This configuration is especially important if the BA amplifier is operating at DC bus voltages of 160 VDC or 320 VDC (e.g., 115 VAC or 230 VAC input power).
Figure 2-5.
Second, another problem that potentially exists with off line connections is 50/60 Hz
electrostatic coupling between the frame of the AC motor and the HI/LO AC input
power. Since LO is referenced to earth ground back at the source, the DC bus of the
amplifier "swings" at 50/60 Hz with respect to the motor frame.
The path of current caused by this coupling between the motor frame and the amplifier
stage passes through the current feedback sensing devices of the amplifier. Depending on
the magnitude of this current, a 50/60 Hz torque disturbance may be present in the
position loop.
To eliminate this problem, an isolation transformer can be used to block the 50/60 Hz
from being seen by the motor frame. Refer to Figure 2-6 for connection of this
transformer.
Version 1.6
Torque to
5-7 in-lb
Schaffner FN2070-10-
LO
06 includes common
HI
mode choke and
ferrite.
A
B
C
GROUNDING
SCREW
Back-propagation Line Filter Connection
Aerotech, Inc.
Installation and Operation
10A slow blow - BA10
20A slow blow - BA20
30A slow blow - BA30
Use 60 degree C copper conductors only
EARTH GROUND
115/230 VAC
50/60 Hz
2-7