Calculation of acceleration and braking time
After selecting the mechanical characteristics and the power of the drive, the
acceleration and braking time is calculated as follows:
Constant torque
area:
(0 < N
< N
)
M
B
Constant power
area:
(N
< N
< N
)
B
M
max
Constant torque &
power area:
(N
< N
< N
)
B
M
max
J
Inertia of the load in kg·m² as viewed from the motor shaft
M
T
Rated torque at base speed in N·m
M
Nmax
Maximum motor speed in rpm.
N
Motor base speed in rpm.
B
N
Motor speed reached after a time period t in rpm
M
Calculation of power with intermittent load
Forming the drive to the right dimensions has to be done with the greatest
care when the application involves a periodical starting and stopping
operation, frequently repeated as in the case of threading with a miller.
torque
speed
Tr
Ts
Tf
0
0
Tc
F. H5/11
Periodic start-stop operation
For a cycle like the one shown in the figure F. H5/11 which includes
acceleration and stopping, the equivalent effective torque T
must be within the S1 dimension given for the drive torque.
Drive selection
When selecting an FM7|FM9 motor, see the manual of the AC spindle
motor that indicates the drive associated with the selected motor.
2 J
N
M
M
------------------------------ - s
t
=
1
60 T
M
2
2
2 J
N
–
N
M
M
B
---------------------------------------------------- - s
t
=
2
120 T
N
M
B
2 J
N
M
t
=
t
+
t
=
-------------------------------------------------- -
3
1
2
120 T
M
-Tp
2
T
t
+
t
+
P
r
f
T
=
------------------------------------------------------ -
R
t
c
Selection criteria
2
2
+
N
M
B
s
N
B
Tp
TL
time
Nm
time
2
T
t
L
s
Nm
of equation
R
HARDWARE
5.
DDS
Ref.1912
· 211 ·