Справочник Пользователя для Mitsubishi Electronics MDS-R

 
 
 

 

 

A2 - 3

 

A typical operation pattern is assumed, and the motor's continuous effective load torque (Trms) is 
calculated from the motor shaft conversion and load torque. If numbers <1> to <8> in the following 
drawing were considered a one-cycle operation pattern, the continuous effective load torque is obtained 
from the root mean square of the torque during each operation as shown in the expression (2-2).  

 

 

Motor 
torque

 

Motor 
speed

 

0

 

0

 

T

3

T

2

 

t

1

 

t

2

 

t

3

 

t

4

 

t

0

 

T

1

 

Time 

T

4

 

T

5

 

T

6

T

7

 

T

8

t

5

 

t

6

 

t

7

 

t

8

 

<1> <2> <3>

<4>

<5>

<6>

<7>

<8> 

 

 
 

Trms = 

 

T1

2

·t1 + T2

2

·t2 + T3

2

·t3 + T4

2

·t4 + T5

2

·t5 + T6

2

·t6 + T7

2

·t7 + T8

2

·t8 

                                                            t0

 ....................   (2-2) 

                

Select a motor so that the continuous effective load torque Trms is 80% or less of the stall torque Tst. 
 

Trms 

≤ 0.8 . Tst  

..................................................  (2-3) 

 
The amount of acceleration torque (Ta) shown in tables 2-1 and 2-2 is the torque to accelerate the load 
inertia in a frictionless state. It can be calculated by the expression (2-4). (For linear acceleration/ 
deceleration) 

 

Ta = 

  (J

L

 + J

M

) 

 N 

95.5 

 ta 

  (N.m)   

..................................................  (2-4) 

 

N 

:  Motor reach speed 

(r/min) 

J

L

  :  Motor shaft conversion load inertia 

(kg.cm

2

) 

J

M

  :  Motor inertia 

(kg.cm

2

) 

ta  :  Linear acceleration/deceleration time constant 

(ms) 

 

 

For an unbalance axis, select a motor so that the motor shaft conversion load torque (friction torque + 
unbalance torque) is 60% or less of the stall. 

 

T

L

 

≤ 0.6 . Tst  

..................................................  (2-5)