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Question:

velocity error of AC servo motor?

I've been searching for a while but can't seem to find anything on it, I'm trying to design a system that will incorporate a servo motor (8kW of power) and I was wondering if anyone could point me to some information about the velocity fluctuations.I know that the error can't be 0 (obviously, though it will be very small). I'm just after something that says I should expect the speed to fluctuate for 0.xx% over a maximum period of a second or something like that. They don't seem to have anything like this in their datasheets.

Answer:

A synchronous motor operates with a winding in its rotor it particularly is hooked as much as an exterior resistor for velocity administration throughout initiate-up, jointly as an induction motor, squirrel caged style has no exterior resistor. The rotor windings are short-circuited on the ends and is nearly a squirrel. the cost of a synchronous motor has no slippage. 2,poles-3600 rpm; 4-poles-1800 rpm; 6poles-1200 rpm jointly as an induction motor has a slip velocity, 2poles- 3540 rpm; 4 poles-1750 rpm; 6poles-1150 rpm.A synchronous motor continually operates with carbon brushes, jointly as induction autos would have none.Synchronous autos are often rated a minimum of 100Hp, jointly as, induction autos may well be rated in fractional Hp.
The error will depend on the load fluctuations. If the fluctuation is a step - i.e., a constant value - the error will eventually disappear. If the load is fluctuating there will always be an error. To find exactly how much the error will be, you have to setup the transfer function, which will depend on the moment of inertia of the motor and drive mechanism, the power of the motor and the load. Then, apply the final value theorem, to find out the error. The toughest parameter to obtain is the moment of inertia. If it is not provided, you may calculate it through a small test. The friction coefficient, likewise. . . .

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