Identify the scale of measurement used.
1 answer:
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Answer:
Explanation:
Motor rating is given in horsepower (hp), it will be converted in watt (W).
Standard to install circuit breaker for an electric circuit is usually 20% ~ 25% more than the Rated Current of the circuit
while
Standard to install overload relay for an electric circuit is usually 20% ~ 25% more than the Running Current of the circuit.
So, to find the maximum capacity of the circuit breaker, rated current of the motor will be multiplied by 1.2 ~ 1.25
Step by Step Explanation:
30hp = 22371W (as 1hp = 745.7)
Assuming unity power factor (cosФ=1) and 208V phase to phase voltage:
Rated Power (watt) = √3 . V.I. cosФ
<em>{if 208V is phase to neutral voltage, then use following formula:</em>
<em> Rated Power (watt) = 3 . V.I. cosФ}</em>
Rated Current = <u>62.169A</u>
So, required maximum rating for circuit breaker is:
20% to 25% of the rated current = 62.17*1.2 ~ 62.17*1.25
=74.6A ~ 77.7A
Hence, any breaker between the above mentioned rating will be appropriate.
Answer:
N₂=20.05 rpm
Explanation:
Given that
R= 19 cm
I=0.13 kg.m²
N₁ = 24.2 rpm
ω₁= 2.5 rad/s
m= 173 g = 0.173 kg
v=1.2 m
Initial angular momentum L₁
L₁ = Iω₁ - m v r ( negative sign because bird coming opposite to motion of the wire motion)
Final linear momentum L₂
L₂= I₂ ω₂
I₂ = I + m r²
The is no any external torque that is why angular momentum will be conserve
L₁ = L₂
Iω₁ - m v r = I₂ ω₂
Iω₁ - m v r = ( I + m r²) ω₂
Now by putting the all values
Iω₁ - m v r = ( I + m r²) ω₂
0.13 x 2.5 - 0.173 x 1.2 x 0.19 = ( 0.13 + 0.173 x 0.19²) ω₂
0.325 - 0.0394 = 0.136 ω₂
ω₂ = 2.1 rad/s
N₂=20.05 rpm