
B-65332EN/01 HANDLING, DESIGN, AND ASSEMBLY 2.MECHANICAL DESIGN
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2.5 MOTOR AND POWER LINE PROTECTION
In order to obtain a desired torque, one amplifier may be used to drive
multiple Dis series motors. If a motor fails or a power line is broken in
such a case, a current larger than the specified level flows into other
motor. In this case, an alarm may be issued because of an insufficient
torque, or an overheat alarm may be issued because of an excessive
current flowing into a drivable motor. In the worst case, an abrupt
increase in current can burn a power line or motor. Take protection
easures as shown below. m
Stator #1
Stator #2
Stator #3
Stator #4 Fuse
Fuse
Fuse
Fuse
PMC
Power line
Thermostat
U
V
W
Terminal block
Servo amplifier module
Power supply module
Ground fault
interru
ter
Three-phase
ower
As shown above, insert a fuse between the servo amplifier module and
each stator. If an excessive current flows through a power line, an
inserted fuse can shut down power. When a fuse with a built-in
microswitch is used, whether the fuse has blown can be known by
applying the signal to the PMC. With this function, the machine can
be stopped more safely with damage minimized when a fuse blows;
or example, the machine can be stopped after retracting the machine. f