Explain why although under no load a motor that spins at a speed below synchronous speed(1500rpm - for 4 pole motor supplied at 50Hz). Why is this effect more pronounced than what should normally be expected?
2007-03-22 20:09:43 · 2 answers · asked by AlexTan 3 in Science & Mathematics ➔ Engineering
No motor ever runs at "synchronous" speed unless it is specially designed to do so. For your situation, or anyone where the power frequency is 60 Hz (cycles), synchronous speed would be about 1800 rpm for most induction or universal motors. Losses and friction slow down the motor to about 1750 rpm. As for your question, I'd look for something that is open in either the armature, or rotor. You might also want to check for rust or other corrosion that is causing the the shaft to bind. If the bearings are using any type of compression seal, the sealing nut might be to tight.
2007-03-22 21:22:31 · answer #1 · answered by Anonymous · 0⤊ 0⤋
I believe that if it is a "synchronous" motor (and that depends on its construction) and is running at less than synchronous speed it is broken. If overloaded it can run slower by slipping synch but that is seriously bad news. If it is an "induction" motor, then it has no "synchronous" speed and will run at whatever its power and load determine.
2007-03-23 03:15:47 · answer #2 · answered by ZORCH 6 · 0⤊ 0⤋