Variable frequency conversion frequency difference characteristics based on,
Whether it is variable speed control, or string resistance speed, are the cost of energy consumption.
Frequency conversion is better, you can smoothly change the synchronous speed.
Change the difference is relatively poor, also known as "energy consumption slip" speed. Synchronous speed unchanged, the slip rate has changed, so the speed changed.
Pole is the pole pair. So that the synchronous speed has changed, you can speed, but can not smooth speed.
