Can someone help me with these questions plz
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:
17,947.02 Hz
Explanation:
length (L) = 62 cm = 0.62 m
tension (T) = 70 N
mass per unit length (μ) = 0.10000 g/cm = 0.010000 kg/m
maximum frequency = 18,000 Hz
f =
f =
f = n x 67.47
18,000 = n x 67.47
n = 266.8≈ 266
the 267th overtone is the highest overtone that can be heard by this person, and its frequency would be 26 x 67.47 = 17,947.02 Hz