Motors generally have to withstand 10 % overspeed. But it in no way means many motors caot withstand much higher over speeds.For example - a 2.2 kW 8 pole motor (750 or 900 r/min rated speed depending on frequency bring 50 or 60 Hz) will use the same bearings and rotor construction as a 5 kW 2 pole motor (3000 or 3600 r/min sync speed for 50 or 60 Hz).This means that one could happily operate the 2.2 kW 8 pole motor at 400 % speed - with constant power operation of course - not constant torque.There are three factors to consider when operating a motor at increased frequency: Will the rotor break apart; will the bearings overheat?; and will the load be happy with constant power operation? (I.e. Reduced torque).In general - small 4 pole motors will easily manage 200 % overspeed operation CONTINUOUSLY. 8 pole small motors can run to 4 times rated speed for constant power operation. One needs to take a little more care with 2 pole small motors because these are already at the limit of standard design factors.My suggestion: Look at the bearing types and check their speed ratings in bearing catalogues. They should run without problems at speeds up to 2/3 of their speed ratings.The rotor breaking up is a little more complicated but look at the physical size of 2 pole motors in the same range - at the maximum power point - and extrapolates what is possible with the motor you're considering, assuming you know the rotor outside diameter.There are of course exceptions (for example - m
ادامه مطلب
برچسب:
نویسنده: فاطمه نصیری
تاريخ: چهارشنبه
8 تير
1401 ساعت: 6:00