Selection criteria
232
5.
SELECTING CRITERIA
Asynchronous spindle motor and servo drive selection
216
DDS
HARDWARE
Ref.1310
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:
Calculation of power with intermittent load
Forming the drive to the right dimensions has to be done with the great-
est care when the application involves a periodical starting and stopping
operation, frequently repeated as in the case of threading with a miller.
For a cycle like the one shown in the figure
F. H 5 / 11 which includes accel-
eration and stopping, the equivalent effective torque
T
R
of equation must
be within the S1 dimension given for the drive torque.
Calculations:
1.
With speed between 0 and 1500 rpm.
2. With speed between 0 and 6000 rpm.
P
N
2
60
-------
2
J
M
N
M
2
1000t
---------------------- k W
2
60
-------
2
0.13 1500
2
1000 0.5
--------------------------------
6.41 kW 1===
P
N
2
60
-------
2
J
M
N
M
2
N
B
2
+
2000t
--------------------------------------kW
2
60
-------
2
0.13 6000
2
1500
2
+
2000 2.5
-------------------------------------------------------
10.89 kW2===
Constant torque
area:
(0 < N
M
< N
B
)
Constant power
area:
(N
B
< N
M
< N
max
)
Constant torque &
power area:
(N
B
< N
M
< N
max
)
J
M
Inertia of the load in kg·m² as viewed from the motor shaft
T
M
Rated torque at base speed in N·m
Nmax
Maximum motor speed in rpm.
N
B
Motor base speed in rpm.
N
M
Motor speed reached after a time period t in rev/min
F. H5/11
Periodic start-stop operation
t
1
2 J
M
N
M
60 T
M
------------------------------- s=
t
2
2 J
M
N
M
2
N
B
2
–
120 T
M
N
B
-----------------------------------------------------s=
t
3
t
1
t
2
+
2 J
M
N
M
2
N
B
2
+
120 T
M
N
B
--------------------------------------------------- s==
0
speed
0
torque
Tc
time
Nm
TL
Tp
-Tp
Tr TfTs
time
T
R
T
P
2
t
r
t
f
+ T
L
2
t
s
+
t
c
-------------------------------------------------------
Nm=
To Next Page
Loading...
