Question

How is maximum torque angle maintained in relay to obtaibn maiximum torque

Answer 1

$\mathfrak{The\:Answer\:is}$

The relay is built such that the angle of maximum torque occurs for phase current lagging the unity power position by 45 degrees or leading the quadrature voltage by 45 degrees. At the maximum torque angle, the relay picks up at 1 percent of rated voltage with 2 A of current.

$\boxed{Hope\:This\:Helps}$

Answer 2

Answer:

Given that α & β are zero of polynomial

f(x)=x

2

−3x−2

therefore α+β=3

αβ=−2

Now, the zero of the required quadratic polynomial are,

2α+β

1

&

2β+α

1

Sum of the roots-

2α+β

1

+

2β+α

1

=

(2α+β)(2β+α)

2β+α+2α+β

=

4αβ+2α

2

+2β

2

+αβ

3(α+β)

=

4×(−2)+2[(α+β)

2

−2αβ]+(−2)

3×3

=

−10+2[9+2×2]

9

=

−10+26

9

=

16

9

Products of roots:-

2α+β

1

×

2β+α

1

=

4αβ+2[(α+β)

2

−2αβ]+αβ

1

=

16

1

Now Req eq.

x

2

−(sum of roots)x+ Product of roots=0

=x

2

−

16

9

x+

16

1

=0

=16x

2

−9x+16=0.