Rockwell Automation LZ Series Linear Motors - Manual (Page 19)

Publication LZ-UM001A-EN-P - January 2008
Installation 19
Motor Coil Thermal
Protection
• Typical digital drives have “RMS” current protection and I 2
T or
estimated temperature vs. time software protection schemes. These
available features should be activated and set according to the motor
model ratings for there application.
• The selected drive should have ±
peak current magnitude limits that
should be set according to the motor’s peak current rating, as a
maximum.
• For drives without adjustable or available motor protection features,
motor fuses (current rating not to exceed motor continuous RMS)
should be installed per the Local and National Electrical Code. The
fuses should be time-delay type and rated for the drive PWM output
voltage.
• Design control circuit to trip at 130°C as necessary.
ATTENTION
LZ linear motors with the thermal protection option will supply
a signal that indicates the motor temperature limit condition.
This signal should be used by the motor control or drive system
to immediately shut down the motor power on an open
condition. Since linear motors are generally not repairable, and
typically highly integrated into the mechanical structure,
redundant motor thermal protection is strongly recommended.
Temperature °C (°F) Resistance in Ohms
Up to 25 (77)
≤ 300
Up to 125 (257)
≤ 1500
Up to 135 (275)
≥ 4000