3. Characteristics 
 
 
 
   
3 - 12
 
(2)  Coasting rotation distance during emergency stop 
The distance that the motor coasts (angle for rotary axis) when stopping with the dynamic brakes 
can be approximated with the following expression. 
 
              L
MAX = 
 
F 
60 
 
▪ {te + (1 + 
J
L
J
M
) ▪ (A ▪ N
2
 + B)} 
L
MAX  :  Motor coasting distance (angle)  [mm, (deg)] 
F
 
:  Axis feedrate  [mm/min, (deg/min)] 
N  :  Motor rotation speed  [r/min] 
J
M  : Motor inertia  [kg
.
cm
2
] 
J
L  :  Motor shaft conversion load inertia   [kg
.
cm
2
] 
te  :  Brake drive relay delay time  (s)  (Normally, 0.03s) 
A  :  Coefficient A (Refer to the table below)  
B  :  Coefficient B (Refer to the table below)  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Dynamic brake braking diagram 
Coasting amount calculation coefficients table 
Motor type 
JM 
(kg・cm
2
) 
Combination  
drive unit type 
A B 
HF44 
MDS-R-V1-20 to 40 
MDS-R-V2-2020 to 4040 
0.67
×10
-9
 
3.14
×10
-3
 
 
2.6 
MDS-R-V2-6040 to 8040  0.65×10
-9
 
3.21
×10
-3
 
HF74 
MDS-R-V1-20 to 40 
MDS-R-V2-2020 to 4040 
1.31
×10
-9
 
6.16
×10
-3
 
 
5.1 
MDS-R-V2-6040 to 8040  1.20×10
-9
 6.73×10
-3
 
HF53 
MDS-R-V1-20 to 40 
MDS-R-V2-2020 to 4040 
5.62
×10
-9
 
3.85
×10
-3
 
 
6.1 
MDS-R-V2-6040 to 8040  5.03×10
-9
 
4.30
×10
-3
 
HF103 
MDS-R-V1-20 to 40 
MDS-R-V2-2020 to 4040 
5.06
×10
-9
 
2.54
×10
-3
 
 
11.9 
MDS-R-V2-6040 to 8040  3.84×10
-9
 
3.35
×10
-3
 
HF153 17.8  3.68×10
-9
 3.23×10
-3
 
HF203 38.3 
MDS-R-V1-60 to 80 
MDS-R-V2-6040 to 8080 
11.41
×10
-9
 4.62×10
-3
 
HF353 75.0 
MDS-R-V1-60 to 80 
MDS-R-V2-6060 to 8080 
8.00
×10
-9
 5.17×10
-3
 
 
 
te
OFF
ON
Emergency stop (EMG) 
ctual dynamic brake operation
N
Time 
Motor rotation speed
Dynamic brake control output
 
OFF
ON
Coasting amount
OFF
ON