The electric motor of the crane operates under a voltage of 300V, while the current in its winding is 20A.
| April 5, 2021 | education
The electric motor of the crane operates under a voltage of 300V, while the current in its winding is 20A. What is the efficiency of the installation if the crane evenly lifts a load of 1 ton to a height of 19 m in 50 seconds.
To solve the problem, let’s translate the weight of the cargo in tons into newtons
F = 1 t = 1000 kg = 1000 * 9.8 = 9800 N.
Find the speed of lifting the load
V = 19 m / 50 s = 0.38 m / s.
The power that is spent on lifting the load
N = F * V = 9800 * 0.38 = 3724 W.
Find the power consumed by the crane
Nk = 20 A * 300 V = 6000 W.
We calculate the efficiency of the installation
Efficiency = N / Nk = 3724 W / 6000 W = 0.62.
Answer: The efficiency of the installation is 0.62.
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