Chapter 11 Selection
11–12
A return operation is executed for a time constant of 50msec for 200mm. The operation is
executed at F20000 in a machine tool vertical axis driven by an HS-SF52 motor. The
regenerative energy per return operation is obtained at this time.
Note the following :
Travel per upward motor rotation : 10mm
Upward stop deceleration torque : 5N·m
Downward stop deceleration torque : 8N·m
Upward torque during downward movement : 0.5N·m
Using expression (11-7), the upward stop regeneration energy ERU is as follows :
ERU = 5.24 × 10
−
5
× 0.85 × 5 × 2000 × 50 − 11 = 11.3 (J)
The acceleration/deceleration distance required to accelerate at the 50msec acceleration/
deceleration time constant to 20000mm/min. is as follows:
20000
×
50
2 × 60 × 1000
= 8.3 (mm)
Therefore, the constant speed travel is 183.4mm.
The downward stop regeneration energy ERD is obtained using the following expression
(11-8).
ERD =
2
π
×
0.85
×
0.5
×
183.4
10
+ 5.24 × 10
−
5
× 0.85 × 8 × 2000 × 50 − 11 = 73.6 (J)
Thus, the regeneration energy per return operation ER is as follows :
ER = 11.3 + 73.6 = 84.9 (J)
11-4-2 Calculation of positioning frequency
Select the regenerative resistor so that the positioning frequency DP (times/minute) calculated by the
regenerative resistor capacity PR (W) and the regenerative energy ER (J) consumed by the
regenerative resistor is within the range shown in expression (11-10). With the unbalance axis, the
number of times for one cycle to raise and lower the axis is judged as DP.
DP < 48 ·
P
R
(times/minute) ................................................. (11-10)
Regenerative resistor specifications for each motor
Motor type Capacity PR (W)
HS-RF43/73 33
HS-SF52/53/102/103 60
HS-SF202 80
(Example)
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