To illustrate the estimation of rating when the load varies periodically, supposea constant-frequency cage induction motor is required to run at a power of 4 kWfor 2 minutes, followed by 2 minutes running light, then 2 minutes at 2 kW, then 2minutes running light, this 8-minute pattern being repeated continuously. Tochoose an appropriate power rating we need to find the r.m.s. power, which meansexactly what it says, i.e. it is the square root of the mean (average) of the square ofthe power
đang được dịch, vui lòng đợi..