1.Torque and Speed of synchronous motor？

Synchronous  motor  Speed and Torque is  inversely proportional to speed.For  samples:49TYJ motor,When motor is 1RPM,The torque will be about  10kgs,When the speed reached 15RPM,The torque is about 2kgs.   

2.where is stepper motor used？

Stepper motor 24BYJ,28BYJ.35BYJ,is used to air-conditioning wind guild board.always used for weep from up to down, give the motor one pulses, the rotor will move one position, moving distance can be very small.

3.what is single-phase shaded pole motor? 

A  shaded-pole motor is a type of AC single-phase induction motor. It is  basically a small squirrel cage motor in which the auxiliary winding is  composed of a copper ring surrounding a portion of each pole auxiliary  winding is called a shading coil. Currents in this coil delay the phase  of magnetic flux for that pole (a shaded pole) enough to provide a  rotating magnetic field. The direction of rotation is from the unshaded  side to the shaded (ring) side of the pole.The effect produces only a  low starting torque compared to other classes of single-phase motors. These  motors have only one winding, no capacitor nor starting switch, making  them economical and reliable. Because their starting torque is low they  are best suited to driving fans or other loads that are easily started.  

4:Torque Conversion Chart