Trinamic QBL4208-61-04-013 - 42 x 42mm Brushless DC Motor, 0.125Nm, 24Vdc, 3.5A 51-0002 数据表

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51-0002
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QBL4208 Manual (V1.01 / 2008-04-01) 
 
Copyright © 2008, TRINAMIC Motion Control GmbH & Co. KG 
 
5 Motor Sizing 
For the optimum solution it is important to fit the motor to the application. The three key parameters 
are peak torque requirement, RMS torque requirement and motor velocity. 
 
5.1  Peak torque requirement 
Peak torque T
P
 is the sum of the torque due to acceleration of inertia (T
I
), load (T
L
) and friction (T
F
): 
 
F
L
J
P
T
T
T
T
+
+
=
 
 
The torque due to inertia is the product of the load (including motor rotor) inertia and the load 
acceleration: 
 
a
J
T
J
=
 
 
The torque due to the load is defined by the configuration of the mechanical system coupled to the 
motor. The system also determines the amount of torque required to overcome the friction. 
 
5.2  RMS torque requirement 
Root-Mean-Square or RMS torque is a value used to approximate the average continuous torque 
requirement. Its statistical approximation is with  
t1: acceleration time 
t2: run time 
t3: deceleration time 
t4: time in a move 
 
(
)
(
)
4
3
2
1
3
2
F
L
J
2
2
F
L
1
2
P
RMS
t
t
t
t
t
T
T
T
t
T
T
t
T
T
+
+
+
+
+
+
=
 
 
5.3 Motor 
velocity 
The motor velocity is also dictated by the configuration of the mechanical system that is coupled to 
the motor shaft, and by the type of move that is to be effected. For example, a single velocity 
application would require a motor with rated velocity equal to the average move velocity. A point to 
point positioning would require a motor with a rated velocity higher than the average move velocity. 
(The higher velocity would account for acceleration, deceleration and run times of the motion profile). 
Figure 5.1 relates rated motor velocity to average move velocity for two point to point positioning 
move profiles.