
B-65232EN/03 DESCRIPTIONS FOR FANUC AC SERVO MOTOR β series 4.SELECTING A MOTOR
- 29 -
(i) Frequency of positioning in rapid traverse
Enter the rapid traverse positioning frequency by the
number of times per minute.
This value is used to check if the motor is overheated or not
by a flowing current during acceleration / deceleration or to
check the regenerative capacity of the amplifier.
(j) Steady-state load torque
• At low speed
The steady-state load torque at low-speed feed time may
be applied even while the motor is at rest. So, the steady-
state load torque needs to have a sufficient margin
relative to the continuous rated torque of the motor.
Set a steady-state load torque so that it is within 70% of
the continuous rated torque.
• At rapid traverse
As the steady-state load torque at rapid traverse time,
enter the torque applied when a movement is made at
steady-state rapid traverse rate. Do not include any
torque required for acceleration/deceleration in this item.
(k) Backlash
Enter the backlash amount between the motor and the final
driven part like table by converting it into the move amount
of the table.
(4) External detector
This item is required to determine the servo system stability
under the influence of an external position detector, mounted on
the motor. When configuring a servo system using a linear scale,
always enter this data.
(a) External position detector
If you want to mount an external position detector outside
the motor, specify the name of the detector and its detection
unit. If you want to use a rotary detector such as a resolver
or rotary encoder, enter the following items in the
"remarks" column.
• Resolver :
Move amount of machine tool per revolution of resolver
Number of wave lengths per revolution of resolver
• Rotary encoder :
Move amount per revolution of pulse coder
Number of pulses (per revolution)
Gear diameter and reduction ratio
(5) Motor specifications
(a) Motor model, Feedback (FB) type
Enter the model name of the motor employed and the
specifications of the built-in feedback unit by using
symbols.
(b) Option
Enter optional specifications, if any, in this blank.