5-6 Power Wiring 3AXD50000011888
5.5 Motor Connections
The wiring between the drive and the motor must consist of 3 wires plus a ground routed in the same conduit. The ground
wire must be continuous and terminated in the motor connection box as well as on the drive ground terminal. The output
power wiring is terminated in the drive on terminals T1, T2, and T3 (see Figure 5-3 Motor Connections).
Note that a direct connection between the drive and motor without any other device is an acceptable means of controlling
the motor, but local safety regulations may require the use of a motor isolation switch or contactor to provide a way to
ensure that power is removed from the motor prior to servicing the tower.
The following warnings illustrate the things to consider when using a permanent magnet motor over an induction
motor. Please review these warnings carefully before operating the permanent magnet cooling tower motor.
WARNING: Motor circuit may have high voltage present whenever AC power is applied, even when motor is
not rotating. Electrical shock can cause serious or fatal injury.
WARNING: RPM AC permanent magnet motors can induce voltage and current in the motor leads by rotating
the motor shaft. Electrical shock can cause serious or fatal injury. Therefore, do not couple the
load to the motor shaft until all motor connections have been made. During any maintenance
inspections, be sure the motor shaft will not rotate.
WARNING: If an output motor isolation contactor is installed, the control must be disabled for at least
200mSec before the contactor is opened. If the contactor is opened while the control is supplying
voltage and current to the motor, the control may be damaged. Before the control is enabled, the
contactor must be closed for at least 200mSec.
WARNING: If an output motor isolation disconnect switch is installed, the control must be disabled for at
least 200mSec before the switch is opened. If the switch is opened while the control is supplying
voltage and current to the motor, the control may be damaged. Before the control is enabled, the
switch must be closed for at least 200mSec.
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