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arsen [322]
1 year ago
12

An installation consists of a 30-kVA, 3-phase transformer, a 480-volt primary, and a 240-volt secondary. Calculate the largest s

tandard size circuit breaker permitted for primary-only protection to be used without applying Note 1 of Table 450.3(B).
Physics
1 answer:
Nikitich [7]1 year ago
5 0

Answer:  45 A

Explanation:

Primary only protection 3-phase

I =  3 phase kVA / ( 1.723 * V)

I = 30000 / ( 1.732 * 480 ) = 36.085 A

Table 450.3(B)

Currents of 9A or more column

primary only protection  = 125%

Max OCPD pri = 125% of I = 1.25 * 36.085 = 45.11 A

 Table 450.3(B) Note 1   does not apply, use next smaller Table 240.6(A)

Next smaller = 45 A

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Gelneren [198K]

Answer:

response

Explanation:

Acceleration is your changing Velocity. An object that is ACCELERATING is experiencing a change in velocity. usually positive. if an object such as a car reduces velocity, it is called deceleration

3 0
3 years ago
Steel blocks A and B, which have equal masses, are at TA = 300 oC and T8 = 400 oC. Block C, with mc - 2mA, is at TC = 350 oC. Bl
shepuryov [24]

Answer:

b) TA = TB = TC

Explanation:

  • When put in contact each other, and isolated, both blocks will exchange heat till they reach to thermal equilibrium.
  • During this process, the body at a higher temperature, will loss heat, tat it will be gained by the other body.
  • The equilibrium condition will be reached when the following equation be met:

       \Delta Q = c_{st}* m_{A} * (T_{fin}  - T_{0A} ) = c_{st}* m_{B} * (T_{0B}  - T_{fin} )

  • Replacing by the values of T₀A = 300º C, and T₀B = 400ºC, and simplifying common terms as mA = mB, we can solve for  Tfin, as follows:

       (400 \ºC - T_{fin}) = (T_{fin} - 300 \ºC) \\ \\  2* T_{fin} = 700\ºC\\ \\ T_{fin} = 350\ºC

  • So, when both blocks reach to equilibrium, they will be at a common final temperature, 350ºC.
  • When put in contact with block C, at the same temperature, at that instant, the three blocks will have the same common temperature of 350 ºC.
  • So, option b) is the right one.
8 0
3 years ago
According to the Theory of Plate Tectonics, which of the following statements is correct?
kramer

Answer:

It's D. The geothermal energy from Earth's core loses most of its heat before reaching the outer layer. The plates on the outer layer have been proven to be moving due to evidence such as earthquakes, volcanic eruptions, and tsunamis.

Explanation:

8 0
3 years ago
Sam is recklessly driving 60 mph in a 30 mph speed zone when he suddenly sees the police. he steps on the brakes and slows to 30
barxatty [35]
For this problem, we use the derived equations for rectilinear motion at constant acceleration. The equations used for this problem are:

a = (v - v₀)/t
2ax = v² - v₀²
where
a is the acceleration
x is the distance
v is the final velocity
v₀ is the initial velocity
t is the time

The solution is as follows;

a = (60mph - 30 mph)/(3 s * 1 h/3600 s)
a = 36,000 mph²

2(36,000 mph²)(x) = 60² - 30²
Solving for x,
x = 0.0375 miles
5 0
3 years ago
The phases of the moon depend on how much of the lighted side of the moon can be seen from Earth.
Ostrovityanka [42]

Answer:

true

Explanation:

if there is no light it's different from when there is

3 0
3 years ago
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