Understanding Motor Controls
4th Edition
ISBN: 9781337798686
Author: Stephen L. Herman
Publisher: Delmar Cengage Learning
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Textbook Question
Chapter 30, Problem 10RQ
How is the dynamic braking force of an alternating current motor controlled?
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A brake jaw, A is pressed against the drum, B. Calculate the brake arm, X(m₂).F= 250NBraking torque = 30Nmµ=0.35Around point A:Fm₂-Nm₁-µm₃=0N=Fm₂/m1+ µm₃MBrake =µ·D/2= µ·D/2MBrake =Fµm₂D/2(m₁- µm₃)(X)m₂=FµD/Mbrake·2(m1- µm₃)(X)m₂=250·0.35.0.3/30·2(0.250-0.35·0.06)=?I don’t get some likely value?
Q7 (12 Marks)
For the system shown in Fig.3:
1- Draw the overall block diagram.
2- Determine the transfer function (Pc(s)/E(s)).
Orifice→
Ps
Actuating error signs)
Flapper
Pb+Pb.
Nozzle.
A
X+X+
Ri
A
I
R2
ㅍ
think
+y
Pc+PC
Figures 4: show a pneumatic controller. The pneumatic
relay has the characteristic
that pc=K pb
, where K>0. What kind of control action does this
controller produce?
a. Derive the mathematical model for the system
b. Derive the transfer function Pc(s)/E(s)
-Solve step by step
Orifice
F+Ph
R₁
Actuating error signal
Flapper
Nozzle.
x+x
F+Pe
think
Chapter 30 Solutions
Understanding Motor Controls
Ch. 30 - Name three methods of braking a motor.Ch. 30 - How is the braking force of drum type brakes...Ch. 30 - Why are mechanical brakes often used on cranes?
Ch. 30 - What is the advantage of dynamic brakes over...Ch. 30 - What is the disadvantage of dynamic brakes when...Ch. 30 - The amount of counter torque developed by a direct...Ch. 30 - When using dynamic braking for a direct current...Ch. 30 - Name three factors that determine the amount of...Ch. 30 - How is dynamic braking for direct current motors...Ch. 30 - How is the dynamic braking force of an alternating...
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