ELECTROMAGNETIC (ELECTRIC) BELL X (Science)

PRINCIPLE:

Agar ek U-shaped core pe wound hui coil ko agar me kisi Voltage source se jorr dun to woh U-Shaped Magnet ki tarhan behave kare gi.

The reason for this act is : 

Current entering the left core has a clockwise direction (see in the fig.) and Current entering the left core has a anticlockwise direction (see in the fig.)

Agar right hand rule aap ko yaad ho to , according to that "grip from the curl of figures in the direction of current" - Aap ka thumb north ki taraf point kare ga !

(verify both the bar of the core with ur hand and then proceed on; see how one end became NORTH and other SOUTH)

CONSTRUCTION:

• U shaped Electomagnet
• Armature
• Screw join
• Voltage source
• Switch
• Gong

MECHANISM OF WORKING:

1.     Click the link to view the flash animation ; to understand the working efficiently: http://www.footprints-science.co.uk/flash/electricbell.swf

2.     Jub aap swithch ko ON karenge, to battery se current electromagnet me jae ga.

3.     Jub current electomagent me se pass hoga to woh Armature coil ko apni taraf attract karega.

4.     Armature k uper jane se; Hammer (jo k armeture se attach he) Gong pe ja kar strike hoga, Aur sound produce hoga : TANNNNG……

5.     Jese hi Armature uper electromagnet se touch hoga, (See in the animation) Screw-join Armature se disjoint ho jae ga.

6.     Iss condition me Circuit will be opened. Battery will stop sending current (q ki aage rasta nahi hai ; samajh lo jese 2 roads ko connect karne wala bridge toot gaya hai)

7.     Since Current is not fllowing though the electomagent as well, Ab woh Electromagnet apni mgnetic properties show nahi kare ga (Ek simple iron piece ki tarha behave kare ga)

8.     q ki ab electromagnet is not in function, no attraction towards Armature.

9.     Electromagnet se attach hua Armature, magnetism na hone ki wajah se, wapis apni position pe chala jae ga (using gravity, but practically spring is used).

10. When armature is restored to its initial position, ab woh wapis screw-join se touch ho jaega. (see animation)

11. jiss ki wajah se Circuit phir se complete (Close) ho jae ga.

12. Yani phir se Electromagnetic zinda hojae ga !

13. Yani phir se armature electromagent se attract hoga ; 

14. Hammer , gong se hit hoga ; Sound will be produced ! TANNNNG…

15.  In this trend bell will function to perform ringing sound !

TANNNNG… TANNNNG… TANNNNG… TANNNNG… TANNNNG… 

Any Queries ????

Electric DC Motor (NCC For Matric A1)

INTRODUCTION:

An Electric motor is a device which produces Mechanical output onthe cost of Electrical input in the form of DC.

CONSTRUCTION:

v  STATOR

Source magnet (Natural/ Electromagnet)

v  ROTOR

Ø  Armature:

Laminated Iron protection to reduce magnetization losses

              i.        Rectangular Coil:

Experiences Torque under DC supply

            ii.        Commutator:

Inverts the direction of current in order to continue unidirectional rotation.

·         (C shaped ) Split rings:

Provide blockage way to reverse current’s direction in the coil.

·         Carbon brushes:

Conducts Electricity b/w circuit and Split rings.

           iii.        Shaft:

Produce mechanical output..

Ø  DC Voltage supply:

Input Source for Electrical energy in DC mode.

WORKING:

                      i.        Play the clip above….

                    ii.        See in the clip, Eek rectangular coil ABCD ko hum ne DC Source se jorra hai, current will follows from A to B , B to C , then C to D and D to A, and then to the battery…

                   iii.        Rod AB and CD force experiences karenge jub woh Source magnet ki magnetic field me hon (practically an Electromagnet).

                   iv.        AB pe downward (Current into the page) aur CD pe upwad (Current out of the page)force lage gi.

                    v.        Ye forces equal and opposite hongi ,but they will not cancel each other according to Newton’s Law, because they have different line of actions (bole to… donu not acting on a same point).

                   vi.        In forces ki wajah se, the coil will rotate, let’s say clockwise (I assumed it to make you understand).

                  vii.        Jub coil straight perpendicular to the magnetic field hojae gi, then, Slip rings circuit ko open kar dengi, yaani koi current flow nahi kare ga…..

                viii.        Coil is situation me inertia ki wajah se rotate hogi in the same direction which I had recently assumed (yani clockwise).

                   ix.        Par jese hi ye coil puri tarhan se rotate ho jae gi, to AB ki jagah CD aur CD ki jagah AB aa jae ga then note karo:

Current will flow from D to C , then C to B , then B to A and to the battery….rite???

                    x.        Sawal???? Is se kia faida???

                   xi.        Socho agar current ka direction wohi rehta , yani A se B se C se D, then forces uss k rotation ko anticlockwise kar deti……(use a diagram, paper lo, AB me out of the page current k lye force nikalo aur CD k lye into the page, dekho kese rotate hui??)

                  xii.        Iss wajah se , yani coil ko ek hi direction me ghumane k le hum current ko ulta flow kara dete hain (D se C se B se A) by using a Commutator.

                xiii.        Iss se forces ki direction bhi ulti hojati hain….

                xiv.        Jahan , pehle who forces coil ko clockwise ghumne se rok rahi theen, ab wohi foces use mazeed clock wise ghumaengi….

                  xv.        Iss tarhan se Current ki direction ko adjust karna k who ek hi direction me coil ko ghummae, COMMUTATION kehlata hai….

                xvi.        Now , in this manner coil sirf clock wise move kare gi.

               xvii.         hum kisi mechanical device ko output shaft se jor denge…. (for example, fan or blades)

              xviii.        So simply we converted DC electrical energy into Mechanical energy…jo k function hai Motor ka….

                xix.        SUBHANALLAH !!!