SINGLE PHASE INDUCTION MOTOR SPEED REGULATION WITH VARIATION OF CAPACITANCE VALUE IN AUXILIARY WINDING
FIELD OF INVENTION:
[001] The present subject matter described herein, relates to a Wall and Pedestal Fan single phase induction motor speed regulation with controlling motor torque by varying auxiliary winding capacitance value with the help of capacitor having different tapping capacitance value, and in particularly to a rotary switch for varying capacitance value in series with auxiliary winding for controlling motor torque.
BACKGROUND AND PRIOR ART:
[002] The single phase induction motor has AC input. The single phase induction motor has rotor and stator. The single phase induction motor has only one phase on the stator winding. Hence the resulting magnetic field in a single phase induction motor does not rotate. For starting any type of motor there must be resulting magnetic field to create torque to rotate the rotor .In single phase induction motor without capacitor the field created by stator winding is positive in half cycle and negative in other half so resulting net field is zero so torque is also zero. Now when capacitor is added to the additional auxiliary winding of stator it creates field which leads by 90 degree to main winding field so the two fields which are 90 degrees to each other, resulting rotating field responsible for start of the fan motor. The capacitor used to start the motor after start may be taken out of circuit because as rotor is rotating each half field of stator creating field in rotor in same direction so producing net field not equal to zero and motor can run continuously if the switch off the power supply to the motor. In existing wall and pedestal fan single phase induction motor, speed of motor is controlled by tapping/looping points from different location of stator winding.
[003] Fig. 1 illustrates block diagram of existing system for speed/torque control in Wall and Pedestal fan single phase induction motor. The single phase induction motor has rotor and stator. The stator has run winding (main winding) 101 and auxiliary winding 102 with a capacitor 103 connected in series. During selection of low, medium and high speed, the AC input is tab in between the coils to vary current in the run winding 101. The main winding 101 has four coils R1, R2, R3, R4 or poles. Similarly the auxiliary winding 102 has four coils A1, A2, A3, A4 or poles. During Low speed selection 106, a supply live point or AC input is connected via switch 107 with tapping 106a between coil A2 and A3 in Auxiliary winding 102. Now coil A1 and A2 shifted to Run (Main) winding 101 which became 6 pole (coil), R1, R2, R3, R4, A1, A2, i.e., and Auxiliary (Start) winding left only with two (2) poles A3, A4 (coil). There is coil imbalance in between the main winding 101 and the auxiliary winding 102 which creates electrical imbalance between main winding 101 and the auxiliary winding 102 and generates noise in single phase induction motor.
[004] During medium speed point 105: when supply of live AC point is connected via switch 107 with tapping 105a between coil A1 and A2 in the auxiliary winding 102. Now coil A1 shifted to Run (Main) winding 101, i.e., Run winding became 5 pole (coil), i.e., R1, R2, R3, R4, A1 and the Auxiliary (Start) winding 102 left only 3 pole (coil), i.e., A2, A3, A4. There is coil imbalance in between the main winding 101 and the auxiliary winding 102 which creates electrical imbalance between main winding 101 and the auxiliary winding 102 and generates noise in single phase induction motor.
[005] During High speed point 104: when supply of live AC point connected via switch 107 with common terminal 104a of two windings. No Pole (Coil) shifting happens, i.e., Run winding remain with 4 pole (coil), i.e., R1, R2, R3, R4 and the auxiliary (Start) winding 102 remains with 4 pole (coil), i.e., A1, A2, A3, A4. There is no coil imbalance in between the main winding 101 and the auxiliary winding 102. Therefore, there is no electrical imbalance between Run and Start winding and noise is also not generated.
[006] In the existing system or induction motor, unwanted noise is generated in Low and Medium speed point due to electrical imbalance in between the run winding 101 and the auxiliary winding 102. Therefore, there is a requirement in the motor to have equal coil balance during low, medium and high speed point. Therefore, there is a need in the art to provide single phase induction motor with a mechanism to distribute equal coils in each speed point and varying flow of current in the windings depend upon the selection of speed point. Further, there is a need in the art to provide a single phase induction motor that is more simple and inexpensive, and which does not create noise and electrical imbalance.
OBJECTS OF THE INVENTION:
[007] The principal objective of the present invention is to provide a single phase induction motor having no electrical imbalance in both Run (Main) and Start (Auxiliary) winding.
[008] Another objective of the present invention is to eliminate noise during low, medium, and high speed point in the single phase induction motor.
[009] Another objective of the present subject matter is to reduce/eliminate noise in induction motor at low and medium speed point.
[0010] Another objective of the present subject matter is to provide a rotary switch to make connection with low, medium, and high speed point.
[0011] Another objective of the present subject matter is to provide two capacitors in series with the auxiliary winding to varying the motor torque and speed.
[0012] Another objective of the present subject matter is to provide a rotary switch having capability to connect a capacitor having different capacitance value such as the capacitor has three tapping points for supplying different capacitance value to motor for different speed operations in various combinations in series with the auxiliary winding of the single phase induction motor.
SUMMARY OF THE INVENTION:
[0013] The subject matter herein disclosed relates to a single phase induction motor with rotor torque/speed control with the help of variable capacitance value in auxiliary winding of the motor. The single phase induction motor has a stator and rotor. The stator is powered by a AC power source. The rotor rotates inside the stator upon generation of magnetic field. The stator has run winding (main winding) and an auxiliary winding (start winding). Further, a single capacitor having different capacitance value is provided to connect with the auxiliary winding in series upon selection of speed by a rotary switch. The single capacitor has three tapping points, such as C1, C2, and C3 (C3= C1+C2) for supplying different capacitance value to motor for different speed operations, such as low, medium, and high speed operations of the motor. The capacitance value of tapping point C2 is more than capacitance value of tapping point C1. The rotary switch is provided for controlling current flow in the stator windings by varying capacitance value in the auxiliary winding by connecting capacitor tapping point C1 or capacitor tapping point C2 or combination of capacitor tapping points C1 and C2 in series. During low speed selection, the rotary switch connects the capacitor tapping point C1 with low capacitance value in series with the auxiliary winding to operate the single phase induction motor at low speed. Due to low capacitance value, low current reaches to the stator. During medium speed selection, the rotary switch connects the capacitor tapping point C2 with high capacitance value in series with the auxiliary winding to operate the single phase induction motor at medium speed. During high speed selection, the rotary switch connects combination of the capacitor tapping point C1 and the capacitor tapping point C2 having combined capacitance value in series with the auxiliary winding to operate the single phase induction motor at high speed. In the present circuit, the coil distribution remains same in both windings, i.e., main winding and the auxiliary winding. Therefore, there is no electrical imbalance and no noise generation issue.
[0014] In another embodiment of the present subject matter, a rotary switch is provided to select the speed point and efficiently connects the low, medium and high speed terminals. The rotary switch has a circular plate having a plurality of extending arms to make contact with low, medium, and high speed terminals of the single phase induction motor. A long lever is provided in the rotary switch to rotate the circular plate along central axis upon application of force. The long lever rotates the circular plate for making connections with low, medium, and high speed terminals. The plurality of extending arms is six in number which extends at an equal angle from each other from the circular plate. The circular plate does not have a pair of extending arm along one diameter. Therefore, the six extending arms are distributed in two semi circular surfaces. One semi circular surface has three arms at equal angle and other semi circular surface has three arms at equal angle. The rotary switch supplies AC input to the single phase induction motor. During low speed selection, the rotary switch connects the low speed terminal and the high speed terminal of the single phase induction motor with two arms from the plurality of extending arms to supply current from the capacitor tapping point C1 to auxiliary winding. During medium speed selection, the rotary switch connects the medium speed terminal and the high speed terminal of the single phase induction motor with two arms from the plurality of extending arms to supply current from the capacitor tapping point C2 to auxiliary winding. During high speed selection, the rotary switch connects the medium speed terminal and the high speed terminal of the single phase induction motor with two arms from the plurality of extending arms to supply current from combination of the capacitor tapping point C1 and the capacitor tapping point C2 to auxiliary winding. During selection of speed point, the rotary switch does not loose connection with the power. With the present rotary switch the imbalance in main and auxiliary winding of single phase induction motor is eliminated.
[0015] In order to further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit scope of the present subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system or methods in accordance with embodiments of the present subject matter are now described, by way of example, and with reference to the accompanying figures, in which:
[0017] Fig. 1 illustrates block diagram of existing method for speed /torque control in Wall and Pedestal fan induction motor;
[0018] Fig. 2 illustrates block diagram of the present method, i.e., capacitor regulation for speed/torque control in wall and pedestal fan single phase induction motor, in accordance with an embodiment of the present subject matter; and
[0019] Fig. 3(a)-3(d) illustrate functioning and working of rotary switch for controlling the speed of wall and pedestal fan single phase induction motor structure, in accordance with an embodiment of the present subject matter.
[0020] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS:
[0021] The subject matter herein disclosed relates to a single phase induction motor with rotor torque/speed control with the help of variable capacitance value in auxiliary winding of the motor. The single phase induction motor has a stator and rotor. The stator is powered by a AC power source. The rotor rotates inside the stator upon generation of magnetic field. The stator has run winding (main winding) and an auxiliary winding (start winding). Further, a single capacitor having different capacitance value is provided to connect with the auxiliary winding in series upon selection of speed by a rotary switch. The single capacitor has three tapping points, such as C1, C2, and C3 (C3= C1+C2) for supplying different capacitance value to motor for different speed operations, such as low, medium, and high speed operations of the motor. The capacitance value of tapping point C2 is more than capacitance value of tapping point C1. The rotary switch is provided for controlling current flow in the stator windings by varying capacitance value in the auxiliary winding by connecting capacitor tapping point C1 or capacitor tapping point C2 or combination of capacitor tapping points C1 and C2 in series. During low speed selection, the rotary switch connects the capacitor tapping point C1 with low capacitance value in series with the auxiliary winding to operate the single phase induction motor at low speed. Due to low capacitance value, low current reaches to the stator. During medium speed selection, the rotary switch connects the capacitor tapping point C2 with high capacitance value in series with the auxiliary winding to operate the single phase induction motor at medium speed. During high speed selection, the rotary switch connects combination of the capacitor tapping point C1 and the capacitor tapping point C2 having combined capacitance value in series with the auxiliary winding to operate the single phase induction motor at high speed. In the present circuit, the coil distribution remains same in both windings, i.e., main winding and the auxiliary winding. Therefore, there is no electrical imbalance and no noise generation issue.
[0022] In another embodiment of the present subject matter, a rotary switch is provided to select the speed point and efficiently connects the low, medium and high speed terminals. The rotary switch has a circular plate having a plurality of extending arms to make contact with low, medium, and high speed terminals of the single phase induction motor. A long lever is provided in the rotary switch to rotate the circular plate along central axis upon application of force. The long lever rotates the circular plate for making connections with low, medium, and high speed terminals. The plurality of extending arms is six in number which extends at an equal angle from each other from the circular plate. The circular plate does not have a pair of extending arm along one diameter. Therefore, the six extending arms are distributed in two semi circular surfaces. One semi circular surface has three arms at equal angle and other semi circular surface has three arms at equal angle. The rotary switch supplies AC input to the single phase induction motor. During low speed selection, the rotary switch connects the low speed terminal and the high speed terminal of the single phase induction motor with two arms from the plurality of extending arms to supply current from the capacitor tapping point C1 to auxiliary winding. During medium speed selection, the rotary switch connects the medium speed terminal and the high speed terminal of the single phase induction motor with two arms from the plurality of extending arms to supply current from the capacitor tapping point C2 to auxiliary winding. During high speed selection, the rotary switch connects the medium speed terminal and the high speed terminal of the single phase induction motor with two arms from the plurality of extending arms to supply current from combination of the capacitor tapping point C1 and the capacitor tapping point C2 to auxiliary winding. During selection of speed point, the rotary switch does not loose connection with the power. With the present rotary switch the imbalance in main and auxiliary winding of single phase induction motor is eliminated.
[0023] Conventional, single phase induction motor has technical problem of electrical imbalance and noise generation due to un-equal distribution of coils in the main winding and the auxiliary winding.
[0024] It should be noted that the description and figures merely illustrate the principles of the present subject matter. It should be appreciated by those skilled in the art that conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present subject matter. It should also be appreciated by those skilled in the art that by devising various arrangements that, although not explicitly described or shown herein, embody the principles of the present subject matter and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be for pedagogical purposes to aid the reader in understanding the principles of the present subject matter and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. The novel features which are believed to be characteristic of the present subject matter, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures.
[0025] These and other advantages of the present subject matter would be described in greater detail with reference to the following figures. It should be noted that the description merely illustrates the principles of the present subject matter. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described herein, embody the principles of the present subject matter and are included within its scope.
[0026] Fig. 2 illustrates circuit diagram of the present single phase induction motor with capacitor regulation for speed/torque control, in accordance with an embodiment of the present subject matter. The single phase induction motor has a stator 200 and rotor. The stator 200 is powered by an AC power source 209. The rotor rotates inside the stator 200 upon generation of magnetic field. The stator 200 has run winding (main winding) 201 and an auxiliary winding (start winding) 202. The main winding 201 has four coils R1, R2, R3, R4 or poles. Similarly the auxiliary winding 202 has four coils A1, A2, A3, A4 or poles. Further, a single capacitor with two tapping points C1 203 and C2 204 is provided to be connected with the auxiliary winding 202 in series upon selection of speed by a rotary switch (as shown in figure 3). The combination of capacitor tapping point C1 203 and C2 204 gives third tapping point which is C3. The third tapping point C3 is equal to combination of capacitance value of C1 and C2. The single capacitor has different capacitance values C1, C2, C3, where the capacitor tapping point C2 204 has high capacitance value than capacitance value of capacitor tapping point C1 203. During Low speed point selection, supply of live AC point is connected via rotary switch 208 (explained in detailed in figure 3) with the capacitor tapping point C1 203 in the auxiliary winding 202. During low speed selection, the capacitor tapping point C1 203 with low capacitance value is connected in series with the auxiliary winding 202. The motor torque and speed with the combination of capacitor tapping point C1 203 and the auxiliary winding 202 is achieved for running the single phase induction motor in low speed. The switch used for the selection is a rotary type. At low speed selection, the switch contact connected three points at a time, i.e., High terminal, medium terminal, and Low terminal. In the low speed selection, the rotary switch connects the capacitor tapping point C1 of low capacitance value in series with the auxiliary winding to operate the single phase induction motor at low speed. Due to low capacitance value, low current reaches to the stator. In this way both main winding 201 and the auxiliary winding 202 remain with their 4 pole (Coil). Therefore, there is no electrical imbalance happen and as a result noise problem is eliminated.
[0027] During Medium speed point 206, supply live AC point connected via the switch 208 with Capacitor tapping point C2 204 in the auxiliary winding 202. For medium speed capacitor tapping pint C2 with high capacitance value is in circuit with the auxiliary winding 202. More motor torque and speed with the combination of capacitor tapping point C2 and auxiliary winding is achieved. At medium speed, the switch contact connected three points at a time. In this way both Run and Auxiliary winding 202 remain with their 4 pole (Coil). Therefore, there is no electrical imbalance happen and as a result noise problem is eliminated.
[0028] During High speed point 205, supply live AC point connected via the switch 208 with combination of Capacitor tapping point C1 and capacitor tapping point C2 in the auxiliary winding 202. For high speed, both tapping points of the capacitor adds their capacitance value (C3=C1+C2) is in series with the auxiliary winding 202. More motor torque and speed with the combination of capacitance value C1+C2 is achieved. At high speed, the switch contact connected three points at a time, i.e., High terminal, Medium terminal, and Low terminal. No electrical imbalance happens and as a result no noise is generated.

CONTINUITY WITH RESPECT TO TERMINAL "S" OF SWITCH
OPERATING CONDITION OF FAN SWITCH TERMINAL-LOW SWITCH TERMINAL-MED SWITCH TERMINAL-HIGH
OFF 1 1 0
LOW SPEED PT. 1 0 1
MED SPEED PT. 0 1 1
HIGH SPEED PT. 1 1 1
LOGIC TABLE OF NEW DEVELOPED SPECIAL TYPE COMBINATION SWITCH
[0029] In above table, ‘1’ is denoted for connection, and ‘0’ for disconnection.
[0030] Figure 3(a)-3(d) illustrates rotary switch with various combination of terminals, in accordance with the present subject matter. Fig. 3a illustrates the connection of rotary switch when it is on OFF condition. Fig. 3b illustrates the connection of rotary switch when it is in Low speed. Fig. 3c illustrates the connection of rotary switch when it is in medium speed. Fig. 3d illustrates the connection of rotary switch when it is in High speed.
[0031] The rotary switch 300 is provided to select the speed point of the single phase induction motor. The rotary switch 300 has a circular plate 301 having a plurality of extending arms 302 to make contact with low speed terminal 303, medium speed terminal 304, and high speed terminal 305 of the single phase induction motor. A long lever 306 is provided in the rotary switch 300 to rotate the circular plate 301 along central axis upon application of force. The long lever 306 rotates the circular plate 301 for making connections with the low speed terminal 303, the medium speed terminal 304, and the high speed terminal 305. The plurality of extending arms 302 is six in number which extends at an equal angle from each other from the circular plate 301. The circular plate 301 does not have a pair of extending arm along one diameter 207. Therefore, the six extending arms 302 are distributed in two semi circular surfaces. One semi circular surface has three arms at equal angle and other semi circular surface has three arms at equal angle. The rotary switch 300 supplies AC input to the single phase induction motor.
[0032] In fan OFF condition: the long lever 306 of the rotary switch 300 connects two arms 302b, 302c with the low terminal (LOW) 303 and the medium terminal (MED) 304 but disconnected with HIGH terminal 305 as illustrated in the figure 3a. AC Supply live (L) voltage goes into the single phase induction motor through HIGH terminal 305 of switch, where the logic of switch terminal low, medium and high is 1, 1, and 0. Accordingly, the switch is connected with all three points. As the HIGH terminal 305 is disconnected therefore supply voltage is also disconnected from the single phase induction motor or load and it act as in OFF condition.
[0033] In fan LOW speed point: the long lever 306 of the rotary switch 300 connects the terminal LOW 303 and the terminal HIGH 305 with two arms 302c, 302d but disconnected with MED terminal 304 as shown in figure 3b. AC Supply live (L) voltage goes into the single phase induction motor through HIGH terminal 305 of the switch and at the same time connected with Capacitor tapping point C1 as explained in figure 2. The switch logic is low, medium and high is 1, 0, and 1. Accordingly, the switch is connected with all three points. The capacitance value of capacitor tapping point C1 203 can be decided as per the speed requirement at that point in the single phase induction motor.
[0034] In fan MED speed point, as illustrated in figure 3c: the long lever 306 of the rotary switch 300 connects the terminal MED 304 and the terminal HIGH 305 but disconnected with LOW terminal 303 as shown in figure 3c. AC Supply live (L) voltage goes into the single phase induction motor, specifically stator through HIGH terminal 305 of the rotary switch 300 and at the same time connected with Capacitor tapping point C2 as explained in the figure 2. The switch logic low, medium and high is 0, 1, and 1. Accordingly, the switch is connected with all three points. The capacitance value of capacitor tapping point C2 can be decided as per the speed requirement at that point in the single phase induction motor.
[0035] In fan HIGH speed point and figure 3d: the long lever 306 of the rotary switch 300 connects with all the three terminals LOW 303, MED 304 and HIGH 305. AC Supply live (L) voltage goes into the single phase induction motor through HIGH terminal 305 of the rotary switch 300 and at the same time connected with both the tapping points C1 and C2 of the capacitor in parallel combination in series with the auxiliary winding as explained in the figure 2. The switch logic low, medium, and high is 1, 1, and 1. The capacitance value of the capacitor become addition of C1 and C2, i.e., C3= C1 + C2.
[0036] During selection of speed point, the rotary switch does not loose connection with the power. With the present rotary switch the imbalance in main and auxiliary winding of single phase induction motor is eliminated
[0037] Although embodiments for the present subject matter have been described in language specific to structural features, it is to be understood that the present subject matter is not necessarily limited to the specific features described. Rather, the specific features and methods are disclosed as embodiments for the present subject matter. Numerous modifications and adaptations of the system/component of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the scope of the present subject matter.
,CLAIMS:We claim:
1. A single phase induction motor with speed control by auxiliary winding capacitance value, the single phase induction motor comprising:
a rotor;
a stator (200) having running winding (201) and a auxiliary winding (202) powered by a power source (209);
single capacitor with variable capacitance value tapping points (C1, C2) (203, 204) provided to connect in series with the auxiliary winding (202);
a rotary switch (300) is provided for controlling current flow in the stator (200) by varying capacitance value of the auxiliary winding,
wherein the rotary switch (300) connects the capacitor tapping point (C1) (203) in series with the auxiliary winding (202) during low speed selection;
wherein the rotary switch (300) connects the capacitor tapping point (C2) (203) in series with the auxiliary winding (202) during medium speed selection;
wherein the rotary switch (300) connects the capacitor tapping point (C1) (203) and Capacitor tapping point (C2) (204) in parallel combination in series with the auxiliary winding (202) during high speed selection.
2. The single phase induction motor as claimed in claim 1, wherein the single capacitor has different capacitance value with tapping points C1 and C2 .
3. The single phase induction motor as claimed in claim 1, wherein the capacitor tapping point (C2) (204) has more capacitance value than Capacitor tapping point (C1).
4. The single phase induction motor as claimed in claim 1, wherein the running winding (201) and auxiliary winding (202) has four poles.
5. The single phase induction motor as claimed in claim 1, wherein the capacitance value of Capacitor tapping point (C1) and the Capacitor tapping point (C2) depends on the speed requirement of the induction motor ().
6. The single phase induction motor as claimed in claim 1, wherein the single phase induction motor has no electrical imbalance by equal distribution of pole in the running winding (201) and the auxiliary winding (202) during high, medium, and low speed selection.
7. A rotary switch (300) for changing speed of induction motor by connecting capacitor with variable capacitance value with tapping points (C1, C2) in series with auxiliary winding (202), the rotary switch (300) comprising:
a circular plate (301) having a plurality of extending arms (302a, 302b, 302c, 302d, 302e, 302e) to make connection with low, medium, high speed terminals (303, 304, 305) of induction motor;
a long lever (306) coupled to rotate the circular plate (301) along central axis for making connections with the low speed (303), medium speed (304), high speed terminals (305), wherein the circular plate (301) and the long lever (306) are mounted on central axis with each other, wherein the long lever (306) connects
the low speed terminal (303) and the high speed terminal (305) with two arms of the plurality of extending arms (302a, 302b, 302c, 302d, 302e, 302e) and capacitor tapping point (C1) in series with auxiliary winding (202) of the in low speed selection,
the medium speed terminal (304) and the high speed terminal (305) with two arms (302d, 302e) of the plurality of extending arms (302a, 302b, 302c, 302d, 302e, 302e) and capacitor tapping point (C2) in series with auxiliary winding (202) in medium speed selection, and
the low speed terminal (303), the medium speed terminal (304), and the high speed terminal (305) with three arms (302d, 302e, 302f)) of the plurality of extending arms (302a, 302b, 302c, 302d, 302e, 302e) and parallel combination of Capacitor tapping points (C3 = C1+C2) in series with the auxiliary winding in high speed selection.
8. The rotary switch (300) as claimed in claim 7, wherein the circular plate (301) has no extending arms along one diameter.
9. The rotary switch (300) as claimed in claim 7, wherein the plurality of arms (302a, 302b, 302c, 302d, 302e, 302e) are six in number, where three are on one semi circular side and three are on opposite semi circular side of the circular plate (301).
10. The rotary switch (300) as claimed in claim 7, wherein the high speed terminal (304) is not connected during connection OFF condition.