Question

Башенный кран равномерно поднимает груз массой 0.5 т на высоту 30 м за 2 мин. Сила тока в электродвигателе равнаи16.5 А при напряжении 220 В. Определите КПД электродвигателя крана

Answer 1

Дано:
m = 0,5 т = 500 кг
h = 30 м
t = 2 мин
J = 16,5 F
U = 220 В
___________
 кпд - ?

1) Полезная мощность:
N пол = m*g*h/t = 500*10*30 / 120 = 1250 Вт
2) Совершенная мощность
N сов = J*U = 16,5*220 = 3630 Вт
3) Коэффициент полезного действия:
КПД = N пол / N сов * 100% = 34 %

Answer 2

Calculation of the Efficiency of the Crane's Electric Motor

To calculate the efficiency of the crane's electric motor, we can use the formula for efficiency:

Efficiency (η) = (useful power output / total power input) × 100%

First, let's calculate the useful power output and the total power input.

Useful Power Output Calculation

The useful power output is the work done by the crane in lifting the load to a certain height. The formula for calculating work done is:

Work (W) = Force × Distance

In this case, the force is the weight of the load and the distance is the height the load is lifted.

Given: - Mass of the load (m) = 0.5 t = 500 kg - Height (h) = 30 m - Acceleration due to gravity (g) = 9.81 m/s^2 (standard value)

We can calculate the work done to lift the load to the given height using the formula:

Work (W) = Force × Distance = mgh

Where: - m = mass of the load - g = acceleration due to gravity - h = height

Let's calculate the work done.

Work (W) = (500 kg) × (9.81 m/s^2) × (30 m)

This will give us the useful power output.

Total Power Input Calculation

The total power input can be calculated using the formula:

Power (P) = Voltage × Current

Given: - Current (I) = 16.5 A - Voltage (V) = 220 V

We can calculate the total power input using the formula:

Power (P) = Voltage × Current = VI

This will give us the total power input.

Efficiency Calculation

Now that we have the useful power output and the total power input, we can calculate the efficiency using the formula:

Efficiency (η) = (useful power output / total power input) × 100%

Let's proceed with the calculations.