机电一体化专业英语教学课件 作者 黄星 夏玉波 Unit 9.pptVIP

STEP 4: Now in order to put the shaft back into the motor case, you will need to reconnect the shaft back into the end cap. In order to do so, you will need to use your thin flat screwdriver to move the (2) two spring loaded brushes out of the way, so that the end cap can fit back over the shaft (see Figure 10 -- 14). STEP 5: Now with both pieces connected, carefully hold them together while you slowly insert the shaft back into the motor case. Tip: You should place something on the opposite side of the motor case to prevent the gear drive, from the shaft, from sliding through the motor case too quickly. The shaft and motor case are both highly magnetized and will have the tendency to pull the shaft quickly through the motor case. If you allow the shaft to slide too quickly through the motor case, your end cap will become separated from the shaft, and you will have to repeat this step over again. Don’t forget to seal the end cap properly, before putting the rest of the motor housing back together (see Figure 15 -- 16). Part I Technical and Practical Reading Passage A The Motor Basics (I) The function of the motor is to convert electrical energy to mechanical energy. Thus, the motor is also classified as an electromechanical device/machine. Basics of Electromagnetic Forces Electromagnetic Force The direction of magnetic flux produced by a permanent magnet is always from N-pole to S-pole.  When a conductor is placed in a magnetic field and current flows in the conductor, the magnetic field and the current interact each other to produce force. The force is called Electromagnetic force (Fig. 9-1). The flemings left hand rule determines the direction of the current, the magnetic force and the flux. Stretch the thumb, the index finger and the middle finger of your left hand as shown in Fig. 9-2. When the middle finger is the current and the index finger the magnetic flux, the direction of the force is given by the thumb. Magnet field produced