
Technical Details
BA Intellidrive User’s Manual
7-18
Aerotech, Inc.
Version 1.4
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 7-16 for connection of this
transformer.
Figure 7-16.
Isolation Transformer Connection (eliminates torque disturbance)
AC LO
AC HI
10A slow blow - BAI10
20A slow blow - BAI20
30A slow blow - BAI30
Use 60 degree C copper conductors only
Earth GND
BAI
AMPLIFIER
This configuration is especially important if the BAI amplifier is operating at DC bus voltages of 160 VDC or 320 VDC (e.g., 115 VAC or 230 VAC input power).
Earth Ground
Grounding
Screw
115/230 VAC
50/60 Hz
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