SIEMENS
8/6
Siemens MD 50.8 · 2017
Appendix
Lists
List of variables to dimension the drive
8
■
Overview of data to dimension drives
Code
Description
Unit
a
Gearbox constant for calculating the radial
force
kNmm
Force application angle
°
b, d, l, y, z
Gearbox constants
mm
C
Additional factor to calculate the radial force
-
cos
Power factor
-
d
Diameter of the input element
mm
d
0
Average diameter of the mounted
transmission element
mm
DC
Cyclic duration factor
%
f
Rated frequency
Hz
F
ax
Permissible axial force
N
f
B
Service factor
-
f
B1
Required service factor
-
f
br
Braking torque correction factor
-
f
Btot
Service factor of the driven machine
-
f
limit
Limit frequency
Hz
F
r
Radial force at the output shaft
N
F
R2
Permissible radial force at the center of shaft
extension (l/2)
N
f
rated
Rated motor frequency
Hz
F
Ravail
Available radial force from the mounted
transmission element
N
F
x
Permissible radial force from out of center
force application point
N
F
xperm1
Permissible radial force, limited by the
bearing service life, at a distance of x from
the shaft shoulder
N
F
xperm2
Permissible radial force, limited by the shaft
strength, at a distance of x from the shaft
shoulder
N
Efficiency
%
i
Transmission ratio
-
I
rated
Rated current
A
I
St
Starting current
A
J
2
Moment of inertia referred to the output
speed of the gearbox
kgm²
J
AD
Moment of inertia of the adapter
kgm²
J
add
Additional moment of inertia, reduced to
motor shaft
kgm
2
J
B
Moment of inertia of the brake
kgm
2
J
Bstp
Moment of inertia of cage and inner ring
kgm
2
J
G
Moment of inertia of the gearbox reduced to
the input shaft
kgm
²
J
mot
Moment of inertia of the motor
kgm
2
J
X
Moment of inertia of the load, reduced to
motor shaft
kgm
2
J
Z
Additional moment of inertia of the high
inertia fan
kgm²
k
Factor for taking into account operating
conditions
-
k
DC
Factor for increased power
-
k
FI
Factor for taking into account the additional
moment of inertia
-
k
HT
Factor for abnormal coolant temperature and
installation altitude
-
Code
Description
Unit
k
M
Factor for taking into account the load torque
while accelerating
-
k
P
Factor for taking into account the required
power and duty cycle
-
L
h10
Nominal bearing service life
h
L
n
Service life of the brake lining until
readjustment
h
L
na
Modified bearing service life
h
L
nmax
Service life of the brake lining until
replacement
h
L
pfA
Measuring surface sound pressure level
dB (A)
L
WA
Sound power level
dB (A)
m
Drive weight without any oil
kg
m
AF
Mass acceleration factor
-
m
fan
Fan weight
kg
m
mot
Motor weight
(without end shield at DE)
kg
m
Bstp
Weight of the backstop
kg
n
1
Input speed of the gearbox
rpm
n
2
Output speed of the gearbox
rpm
n
dis
Disengage speed
rpm
n
br
Braking speed
rpm
n
max
Maximum speed
rpm
n
rated
Rated speed
rpm
P
1
Actual steady-state power of the motor
kW
P
DC
Power for the new duty cycle
kW
P
mot
Motor power
kW
P
perm
Permissible motor power
kW
P
rated
Rated motor power
kW
P
req
Required input power
kW
P
S
Actual steady-state power of the motor
kW
Q
perm
Permissible operating energy
J
r
Radius of the output element
m
R
ex
Exact number of teeth ratio
-
s
br
Braking distance
m
s
Gap
Brake air gap
mm
s
Gapmax
Maximum brake air gap
mm
t
1
Application time of the brake
ms
t
2
Disconnection time
ms
t
3
Slipping time
ms
t
11
Response time
ms
t
12
Rise time
ms
t
br
Braking time
s
t
R
Duty cycle (decimal)
-
t
sp
Cycle duration
ms
T
2
Geared motor output torque
Nm
T
2req
Required output torque of the driven machine
Nm
T
2N
Maximum output torque of the gearbox
Nm
© Siemens AG 2017