Mitsubishi MELDAS HS Series, Технические характеристики и инструкция по эксплуатации

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Chapter 11 Selection
11–2
11-1 Outline
11-1-1 Servomotor
There are limits to the lineup of the intelligent servomotor. As the regenerative resistor is fixed to the
built-in type, the repeated positioning frequency is limited.
If the servomotor does not comply with the following items, use the MDS-B-V1/V2/SVJ2 servo drive
unit and HA/HC Series servomotor.
(1) Motor inertia
The servomotor series is mainly categorized according to the motor inertia size. The features in
Table 11-1 are provided according to the motor inertia size.
Table 11-1 Motor inertia
Motor model Medium inertia motor Low inertia motor
Motor type HS-SF HS-RF, HS-MF
Inertia The flange size is large.
The inertia is comparatively large. The flange size is small.
The inertia is small.
Acceleration/deceleration The acceleration/deceleration time
constant does not change much
even for a low inertia load.
The effect of the motor inertia is
large.
Acceleration/deceleration is
possible with a short time constant
in respect to low inertia loads.
The effect of the motor inertia is
small.
Installation The motor size in respect to the
output capacity is large, and the
installation space is large. The motor size in respect to the
output capacity is small, and the
installation space is smaller.
Disturbance
characteristics The effect of disturbance is small. The effect of disturbance is large.
Speed fluctuation The effect of the torque ripple is
small, and speed fluctuation does
not occur easily. The effect of the torque ripple is
large, and speed fluctuation occurs
easily.
Suitability Suitable for high precision
interpolation control Suitable for high speed positioning
Select a medium inertia motor when interpolation precision is required, or for machines having a
large load inertia. Select a low inertia motor when a shorter positioning time is required by
machines having a small amount of inertia. Normally use the HS-SF motor for the machine tool
feed axis. Consult with Mitsubishi when using a low-inertia motor for the feed axis.
The servomotor has an optimum load inertia scale. If the load inertia exceeds the optimum range,
the control becomes unstable and the servo parameters become difficult to adjust. When the
load inertia is too large, decelerate with the gears (The motor axis conversion load inertia is
proportional to the square of the deceleration ratio.), or change to a motor with a large inertia.
(2) Rated speed
Even with motors having the same capacity, the rated speed will differ according to the motor.
The motor's rated output is designed to be generated at the rated speed, and the output P (W) is
expressed with expression (11-1). Thus, even when the motors have the same capacity, the
rated torque will differ according to the rated speed.
P = 2
π τ
(W) ................................................. (11-1)
N : Motor speed (r/min)
T : Output torque (N
⋅
m)
In other words, even with motors having the same capacities, the one with the lower rated speed will
generate a larger torque. When actually mounted on the machine, if the positioning distance is short
and the motor cannot reach the maximum speed, the motor with the lower rated speed will have a
shorter positioning time. When selecting the motor, consider the axis stroke and usage methods, and
select the motor with the optimum rated speed.
N
60