Предмет: Физика, автор: Gavlyash489

Скорость движения трамвая 72 км/ч, сила тяги электродвигателя 1,2 кН. Каков КПД электродвигателя, если напряжение в контактной сети 600 В,а сила тока в двигателе 50 А?

А)75%
В)80%
С)85%
D)90%

Ответы

Автор ответа: Аноним

n - КПД
n= Pп/W
W = Pt
P = IU
Pп = Fт*V
n = Fт*V/Pt
t = 1сек
n = Fт*V/P = 20*1200/(600*50) = 0.8
n = 80%

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