Rockwell Automation 2098-IPD-xxx Ultra5000 Intelligent Positioning Drives Installation Manual - Manual (Page 132)

Publication 2098-IN001E-EN-P — April 2002
B-20 Interconnect Diagrams
Using an Emergency Stop
Contactor
Some applications require that a contactor be inserted between the
motor and Ultra5000 for emergency stop purposes. To determine if
this is necessary, perform a hazard analysis of the machine. If used,
the contactor must not simply break the motor current, it must switch
a 3-phase resistive load in parallel with the motor windings. The three
resistors provide dynamic braking and a category zero stop. The
resistors also prevent continuous arcing at the main contacts when
breaking DC currents, such as when the motor is at stall.
It is important to sequence the E-stop string to disable the drive prior
to or at the same time the contactor is released. Conversely, upon
power-up the contactor must be fully engaged before the drive is
enabled. Use an auxiliary contact on the contactor for the drive enable
circuit for sequencing.
Shield and ground cable connection methods are shown in Figure
B.19 .
ATTENTION
!
To avoid personal injury and/or equipment damage,
do not simply break the motor current. This can
result in very high voltages due to motor inductance,
prolonged arcing in the contactor, and eventually
can cause fire in extreme cases.
ATTENTION
!
Implementation of safety circuits and risk assessment
is the responsibility of the machine builder. Please
reference international standards EN1050 and EN954
estimation and safety performance categories. For
more information refer to Understanding the
Machinery Directive, publication SHB-900.