Question

正弦电压U的最大值为311V,初相位为负60,求它的瞬时值解析式,并写出t=0.0025时的瞬时值.

Answer 1

最大值：Um = 311 初相位：φ = - 60 * 2Π / 360 = - Π / 3 频率：f = 50 (假设）

角频率:ω = 2Πf = 100 Π

u = Um sin (ω t - Π / 3 ) = 311 sin (100 Π t - Π / 3 )

t = 0.0025 u = 311sin (100 Π * 0.0025 - Π / 3 ) = 311sin ( - Π / 12 ) = - 80.5 V