Allen-Bradley ArmorStart 290E, User Manual

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58 Rockwell Automation Publication 290E-UM001B-EN-P - June 2012
Chapter 2 Installation and Wiring
Power Distribution The type of transformer and the connection configuration feeding an
ArmorStart LT Bulletin 294E plays an important role in its performance
and safety.
Delta/Wye with Grounded Wye Neutral
Figure 33 -
Delta/Wye with Grounded Wye Neutral is the most common type of
distribution system. The grounded neutral provides a direct path for common
mode current caused by the drive output.
AC Line Voltage Incoming voltage imbalances greater than 2% can cause large unequal currents
in a drive. An input line reactor may be necessary when line voltage imbalances
are greater than 2%.
Line Reactor
In general, ArmorStart LT does not require line reactors. In most applications,
the ArmorStart LT is further away from the power distribution panel, therefore
the length of cable provides additional impedance as compared to an in-panel
solution.
Therefore, ArmorStart LT does not define a minimum line impedance
specification, and does not require a line reactor. Its design trades the external
reactor supplied by the customer for an internal fan integral to the controller.
This improves the overall life of the product. To achieve maximum electrical life
of Bulletin 294, a minimum 800 uH line reactor for the group can be applied to
extend total service life.
In addition, if line disturbance mitigation is also necessary, the ArmorStart LT is
equipped with an EMI filter and when used with a shielded motor cable reduces
the impact of the power switching components. For CE compliant installations
SHOCK HAZARD: ArmorStart LT requires the use of grounded Wye
power systems.