split capacitor motors have a wide variety of applications depending on the design. Single phase induction motors are not self-starting and hence Shaded pole motor helps in starting the single phase Induction motors. split-phase motor uses a switching mechanism that disconnects the start winding from the main winding when the motor comes up to about 75% of rated speed. pay careful attention to the application requirements before choosing a motor for replacement of a failed one or for a new design application. the distribution of flux through the poles is greatly influenced by the shading coils. key: first, size the motor to the application but, just as importantly, understand the characteristics of the major types of single-phase motors -- characteristics that go right to the heart of matching a motor to an application. the details of characteristics of shaded pole motor will be discussed later. but neither should you specify a motor too powerful -- either because of its power or its inherent design characteristics.
and the starting current, usually 450 to 575% of rated current, is much lower than the split-phase due to the larger wire in the start circuit. this shifting effect is equivalent to the physical movement of the poles, which is nothing but the rotation of poles. Some important characteristics are also pointed along with the operation of shaded pole motors. make it a point to check with your motor manufacturer for technical support in these areas. construction and working of shaded pole induction motors are discussed in this article. operation of the motor can be understood by referring to figure which shows one pole of the motor with a shading coil. the part of the pole which has the coil is called the shaded part and the other part of the pole is called unshaded part. absence of centrifugal switch eliminates the possibility of motor failure due to faulty centrifugal switch mechanisms.
a slot is cut across the lamination of the pole. a squirrel-cage motor connected to a single-phase line develops no starting torque, but having been started by some external means, it runs approximately like a polyphase motor. obviously, you don't want to specify a motor too small for the application, thus resulting in electrical stresses that cause premature motor failure. the start winding is made with smaller gage wire and fewer turns relative to the main winding to create more resistance, thus putting the start winding's field at a different angle than that of the main winding, and causing the motor to rotate. only disadvantage to a cap-start/cap-run motor is its higher price -- mostly the result of more capacitors, plus a starting switch. type, figure 4, combines the best of the capacitor-start/induction-run motor and the permanent split capacitor motor. the stator is of salient pole type and the rotor is of squirrel cage type.-phase AC motors are as ubiquitous as they are useful serving as the prime power sources for a seemingly limitless array of small-horsepower applications.
due to fixed of position of shading coils, the direction of rotation of such motors cannot be changed. in fact, these are usually considered "disposable" motors, meaning they are much cheaper to replace than to repair. preceding information establishes guidelines for determining the proper motor type for your application. not choosing the correct motor type and horsepower can cause repeated motor failure and equipment downtime. though they lack the higher efficiencies of their three-phase siblings, single-phase motors -- correctly sized and rated -- can last a lifetime with little maintenance. this disconnects not only the start winding, but also the capacitor when the motor reaches about 75% of rated speed. permanent split capacitor (psc) motor, figure 3, has neither a starting switch, nor a capacitor strictly for starting. split-phase motor's simple design makes it typically less expensive than other single-phase motor types made for industrial use.
this effect is nothing but the rotation of poles from left to right. rotor of shaded pole induction motors is squirrel cage type rotor. pole induction motor has no commutator, brushes, collector rings, contactors, capacitors or moving switch parts, so it is relatively cheaper, simpler and extremely rugged in construction and reliable. advantage of the capacitor-start/capacitor-run type motor: it can be designed for lower full-load currents and higher efficiency. but low torque, low efficiency, and less sturdy mechanical features make shaded-pole motors impractical for most industrial or commercial uses where higher cycle rates or continuous duty are the norm. rotor is of the squirrel-cage type and is under the influence of this moving field. a 2 poled stator gives a synchronous speed of 3000 rpm while a 4 poled stator speed will be 1500rpm for 50hz supply. instead, it has a run-type capacitor permanently connected in series with the start winding.