0195136047.pdf

16.2 FEEDBACK CONTROL SYSTEMS 797

−

−

−

+

+

−

+ −

+

Ra(1 + τas)

1

B(1 + τms)

Vt(s) Te(s)+ 1

(b)

(a)

Ωm(s)

Σ

TL(s)

ea

vt

vf

if

Lf

Rf

La

ωm

Te

TL

ia

Ra

Ia(s)

Ea(s)

Km

Km

−

−

+

Ra(1 + τas)

1

TL

Kmea

Js

Vt(s) Te(s)+ 1

(c)

(d)

Ωm(s)

Σ

TL(s)

Ia(s)

Ea(s)

Km

Km

+

−

+

−

ia
vt ea

Ceq =

La Ra

K^2 m

J

Geq =

K^2 m

B Z

L^ =

Figure E16.2.1(a)Model of a separately excited dc motor.(b)Block diagram representing Equations (8)
and (9).(c)Block diagram representing Equation (11).(d)Analog electric circuit for a separately excited
dc motor.