Mitsubishi Electronics MDS-R ユーザーズマニュアル
Appendix 2. Selection
A2 - 7
(2) For unbalance axis
The regenerative energy differs in the upward stop and downward stop for an unbalance axis. A
constant regeneration state results during downward movement if the unbalance torque is the
same as or larger than the friction torque.
constant regeneration state results during downward movement if the unbalance torque is the
same as or larger than the friction torque.
Regenerative energy
A regenerative state only occurs when deceleration torque (downward torque) is generated.
E
RU
= 5.24
10
-5
T
du
N
t
d
– Ec (J)
(
2-7)
: Motor reverse efficiency
T
du
: Upward stop deceleration torque
(N
m)
N
: Motor speed
(r/min)
t
d
: Deceleration time (time constant)
(ms)
Upward stop
Ec
: Unit charging energy
(J)
A regenerative state occurs even during constant rate feed when the upward torque Ts during dropping is
generated.
Calculate so that Ts = 0 when Ts is downward.
generated.
Calculate so that Ts = 0 when Ts is downward.
2
T
s
L
E
RD
=
∆S
+ 5.24
10
-5
T
dd
N
t
d
– Ec (J)
(
2-8)
: Motor reverse efficiency
T
s
: Upward torque during dropping
(N
m)
L
: Constant speed travel
(mm)
∆S : Travel per motor rotation
(mm)
T
dd
: Downward stop deceleration torque (N
m)
N
: Motor speed
(r/min)
t
d
: Deceleration time (time constant)
(ms)
Downward stop
Ec
: Unit charging energy
(J)
The regenerative energy per cycle (E
R
) is obtained using expression (2-9) using one reciprocation as one cycle.
E
R
=E
RU+
E
RD
(J)
(
2-9)
(Example)
Using a machine tool vertical axis driven by an HF153 motor, reciprocation is carried out with F30000 at an
acceleration/deceleration time constant of 100ms for a distance of 200mm. Obtain the regenerative energy
acceleration/deceleration time constant of 100ms for a distance of 200mm. Obtain the regenerative energy
er reciprocation operation in this case.
p
Where: Servo drive unit
: MDS-R-V1-80
Travel per motor rotation
: 10 mm
Upward stop deceleration torque
: 20 N
m
Downward stop deceleration torque
: 30 N
m
Upward torque during downward movement : 3 N
m
Using expression (2-7), the upward stop regenerative energy E
RU
is as follows:
E
RU
= 5.24
10
-5
0.85203000100 – 46 = 221.2 (J)
The acceleration/deceleration distance required to accelerate at the 100ms acceleration/deceleration time
onstant to 30000mm/min. is as follows:
c
30000
100
2
601000
= 25 (mm)
Therefore, the constant speed travel is 150mm.
T
he downward stop regenerative energy E
RD
is obtained using the following expression (2-8).
2
0.853150
E
RD
=
10
+ 5.24
10
-5
0.85303000100 – 46 = 595.2 (J)
Thus, the regenerative energy per reciprocation operation E
R
is as follows:
E
R
= 221.2 + 595.2 = 816.4 (J)