Basic Electrical Installation Work

| Kategorie: Kniha  |

Strana 223 z 399

Jak získat tento dokument?






Poznámky redaktora
Transformers A transformer electrical machine which used change the value of alternating voltage. A transformer, shown Fig. 10. supply Stator winding Laminated stator Fixing holes Cage rotor Copper shading rings FIGURE 10. This magnetic flux induces emf the secondary winding, as . trans- former will only work when alternating voltage connected. Reversal rotation theoretically possible by moving the shading rings the opposite side the stator pole face.Baisc Electrical Installation Work 212 a. An alternating voltage applied the primary winding produces alter- nating current, which sets alternating magnetic flux throughout the core. They vary size from miniature units used in electronics huge power transformers used power stations. Figure 10. Shaded pole motors are constant speed machines with very low starting torque and are used very light loads such oven fans, record turntable motors and electric fan heaters. Shaded pole motors The shaded pole motor simple, robust single-phase motor, which is suitable for very small machines with rating less than about 50W.20 shows shaded pole motor.20 Shaded pole motor. supply such battery. has cage rotor and the moving field produced enclosing one side each stator pole solid copper or brass ring, called shading ring, which displaces the magnetic field and creates artificial phase shift. will not normally work from d. However, practice this often not simple process, but the motors are symmetrical and sometimes easier reverse the rotor removing the fixing bolts and reversing the whole motor. Definition A transformer electrical machine which used change the value of an alternating voltage. Most them operate very small motors in domestic and business machines where single-phase supplies are most common.c.21, consists two coils, called the pri- mary and secondary coils, windings, which are insulated from each other and wound the same steel iron core.c. There are more motors operating from single-phase supplies than all other types motor added together