Electrostatic type instruments working principle, construction, torque equation and extending range

Working principle, construction , torque equation and extending range of electrostatic type instruments 

Hello readers,

                         In this post we are going to discuss about construction principle and torque equation of electrostatic type instruments.

Working principle of electrostatic type instruments:

Working principle of electrostatic type instruments is electrostatic effect.

What is meant by electrostatic induction??

To understand clearly about electrostatic effect see the below circuit.

1.Here the two plates are being charged by a high voltage battery. 

2. Due to this one of the plate gets positive charge and the other plate gets negative charge.

3. Here the deflecting torque is produced by this static electrical field due to attraction present between these opposite charges.

4. The plates move because of the electrostatic force(attraction between plates) that has been produced because of this induced charges.

This effect is called electrostatic effect. 

Construction of electrostatic type instruments:

1. Linear type electrostatic instruments.

2. Rotatory type electrostatic instruments.

Linear type electrostatic instruments:

1. Here one of the plates is fixed and the other plate is movable and these plates are charged as shown in the above circuit. So one of the plate gets positive charge and the other plates gets negative charge. Due to this there will be force of attraction between the plates so the movable plate moves towards the fixed plate until movable plate gains maximum amount of electrostatic energy. Fixing pointer to the movable plate we can measure the voltage. These are called linear type electrostatic instruments.

Rotatory type electrostatic instruments:

2. Here we have a rotatory plate. Due this movement of rotatory plate there may be force of attraction or repulsion between the plates. These are called rotatory type electrostatic instruments.

Torque equation of electrostatic type instruments:

Now let us see torque equation of both linear type electrostatic instruments and rotatory type electrostatic instruments.

Torque equation of linear type electrostatic instruments:

Let us see in detail about torque equation of liner type electrostatic instruments.

Observe the following diagram.

1.Here plate A is fixed and it is positively charged and plate B is movable and it is negatively charged.

2. As the forces are opposite we have attraction between plates. So there will be linear motion between these plates.

3. As there is force between these plates at equilibrium electrostatic force will be equal to spring force.

4.Now electrostatic energy stored in the plate is given by,

                               

                                                                                          

5.Now let us increase the voltage by a small amount let it be dv due to this there will be displacement of plate let the displacement be dx. So work done against the spring force due to displacement of  plate B be F.dx.  Relation between current and applied voltage is given by,

                                                     

6. Now the input energy from this value of electric current is given by,

7. Now the change in this stored energy is given by,

                                                      

8. Now apply principle of energy conservation by neglecting the higher order terms in the expression.

Input energy to the system = increase in the stored energy of the system + mechanical work done by the system.

By substituting all the values we get,

                                     

Now the equation of force from the above equation is given by,

                                       

Torque equation of rotatory type electrostatic instruments:

Let us see in detail about torque equation of rotatory type electrostatic instruments.

Observe the following diagram.

1. By replacing F, dx in equation (1)  by Td , dA respectively we get deflecting torque of rotary type electrostatic instruments.

2. So the deflecting torque is given by,

                                                 

3.At steady state we have controlling torque is given by, Tc = K × A. Where A is the deflection and it is given by,

                                                   

As the deflection is directly proportional to square of voltage we have non- uniform scale.

Hence we have derived  torque equation of  electrostatic type instruments i.e for liner type electrostatic instruments and  rotatory type electrostatic instruments.

Generally electrostatic type instruments are used for measuring high voltages.

The main advantage of using electrostatic type instruments as voltmeters is we can extend the range of voltage that is to be measured.

Methods to extend the range of voltage to be measured for electrostatic instruments:  

1. Resistance potential dividers.

2.Capacitor multiplier technique.

Resistance potential dividers to extend the range of voltage to be measured for electrostatic instruments:  

Now let us see how to extend the range of voltage to be measured by using resistance potential dividers.

To understand it see the below circuit.

Circuit diagram of resistance potential dividers to extend the range of voltage to be measured for electrostatic instruments:  

The following diagram shows the circuit to extend the range of voltage to be measured by 

electrostatic instruments using resistance potential dividers.

                                               

Procedure to extend the range of voltage to be measured by electrostatic instruments using resistance potential dividers:

1. Across r which is total resistance apply the voltage which is to be measured.

2. Across R which is a part of total resistance r connect an electrostatic capacitor.

3.Make one assumption that the capacitor which is connected is having infinite leakage resistance in case if we apply dc voltage. Here the multiplying factor is ratio of resistances i.e, r/R. Multiplying factor in ac case is same as dc case.

Capacitor multiplier technique to extend the range of voltage to be measured for electrostatic instruments: 

Now let us see how to extend the range of voltage to be measured by electrostatic instruments

 using capacitor multiplier technique.

To understand it see the below circuit.

Circuit diagram of capacitor multiplier technique to extend the range of voltage to be measured for electrostatic instruments:  

The following diagram shows the circuit to extend the range of voltage to be measured by electrostatic instruments using capacitor multiplier technique.

Procedure to extend the range of voltage to be measured by electrostatic instruments  using capacitor multiplier technique:

Let us calculate the multiplying factor.

1. From diagram we have series combination of capacitors. The equivalent capacitance is given by

                                            

2. Voltmeter impedance is given by Z1 = 1/jωC1 . Now total impedance is given by,

                                   

                                                         

3.Multiplying factor is given by,

                                                      Z/Z1 = 1 + C2 / C1.

In this way we can extend the range of voltage to be measured by electrostatic instruments with the help of  resistance potential dividers and capacitor multiplier technique.

Advantages of electrostatic type instruments:

1. As the deflection torque is directly proportional to square of voltage we can measure both a.c and d.c voltages by using electrostatic type instruments.

2.High values of voltage can be measured  using electrostatic type instruments.

3. Current drawn by electrostatic type instruments  is low so power consumption of electrostatic type instruments is low.

Disadvantages of electrostatic type instruments:

1.Electrostatic type instruments have non uniform scale.

2.Electrostatic type instruments are larger in size.

3.Electrostatic type instruments are costlier compared to other type of instruments.

4.Various operating forces present in electrostatic type instruments are small in magnitude.

Today we have learnt working principle, construction , torque equation and extending range of electrostatic type instruments.

You can download this article about working principle, construction , torque equation and extending range of electrostatic type instruments as PDF here.                     

                                                                                 

January 11, 2017 at 06:32PM by EEE, ADBU

Speed Control Methods Of DC Motor

Speed Control Methods Of DC Motor

DC motors brought us revolutionary changes in industrial and domestic applications.This all because of an unique feature of DC motors i.e, speed controlling of DC motors .Compared to Synchronous motor , Induction Motor controlling the speed of DC series or DC shunt motor is very easy and efficient. Now let's get into the detailed explanation on how we can control speed of DC motor ?

What is speed control?

Speed controlling is nothing but changing our DC motor speed according to our requirements.We have different methods to control speed.As we know DC motors are majorly categorized into DC series motors and DC shunt motors.

Speed Control Methods of a DC Motor 

In DC motor an EMF induced in armature conductors due to the rotation of armature in magnetic field this is called back EMF (Eb). The magnitude of the E_b can be given by the EMF equation of a DC generator.

Eb = ^PØNZ/_60A

(where, P = no. of poles, Ø = flux/pole, N = speed in rpm, Z = no. ofarmature conductors, A = parallel paths)

E_b can also be given as,
E_b = V- I_aR_a
thus, from the above equations
N = ^E_b 60A/PØ
but, for a DC motor A, P and Z are constants
Therefore, N ∝ K ^E_b/_Ø          (where, K=constant)

This shows the speed of a dc motor is directly proportional to the back emf and inversely proportional to the flux per pole.

January 07, 2017 at 03:17PM by EEE, ADBU

Voltage regulation of synchronous machine by zero power factor method or potier triangle method

Calculation of voltage regulation of synchronous machine by M.M.F method or ampere turn method

Calculation of voltage regulation of synchronous machine by M.M.F method or ampere turn method 

In this post let us see how to calculate voltage regulation of synchronous machine by M.M.F method or ampere turn method.

Requirements for Calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method:

1.  Any synchronous machine requires m.m.f to induce rated terminal voltage on open circuit. This m.m.f is denoted by Fo. To calculate this we conduct open circuit test on synchronous machine.

2. In the same way a synchronous machine also requires  m.m.f  to act opposite to armature reaction such that it helps full load current to flow in the armature.This m.m.f is denoted by Far.To calculate this we conduct short circuit test on synchronous machine.

3. From open circuit test on synchronous machine we obtain open circuit characteristics of synchronous machine and from short circuit test on synchronous machine we obtain short circuit characteristics of synchronous machine.

For details about open circuit test on synchronous machine , open circuit characteristics of  synchronous machine and short circuit test on synchronous machine , short circuit characteristics of synchronous machine refer below link.

Graph for calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method:

The graph shown below is the combined graph of open circuit characteristics of synchronous machine and short circuit characteristics of synchronous machine.

Note: As in many cases we don't know the number of turns though m.m.f is product of current and turns here we express m.m.f in terms of field current.

What is meant by Fo and Far ?

Now let us see in detail about Fo and Far

1.Fo is the field m.m.f required to induce rated terminal voltage when the armature is open circuited. This value can be obtained from open circuit characteristics of synchronous machine by conducting open circuit test on synchronous machine.

2. Synchronous impedance has two components namely synchronous reactance and armature resistance .

3. Synchronous resistance further contains two components namely armature leakage reactance and armature reaction reactance.

4. In short circuit test on synchronous machine field m.m.f is required to overcome drop across armature resistance, leakage reactance and armature reaction and allow full load current to pass through short circuited armature. But the drop due to armature resistance, leakage reactance is very small and can be neglected. So the m.m.f required to allow full load current to pass through short circuited armature by balancing armature reaction is Far which can be obtained from short circuit characteristics of synchronous machine by conducting short circuit test on synchronous machine.

Calculation of resultant m.m.f Fr for calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method:

When the alternator supplies full load the total field m.m.f Fr is the vector sum of Fo and Far. And this depends on the  power factor of load which the synchronous machine is supplying.

Now lets see how Fr is calculated for different load conditions:

Zero lagging power factor load:

1. If the load has zero power factor lagging then the armature reaction is demagnetizing in nature.

2. So resultant m.m.f Fr is algebraic sum of two vectors Fo and Far.

3. So here field m.m.f should be able to provide not only rated terminal voltage but also it should overcome demagnetizing armature reaction.

This can be represented as follows:

OA = Fo

AB = Far

OB = Fr = Fo + Far

This shows total field m.m.f is greater than Fo.

Steps to draw vector diagram for calculating resultant m.m.f Fr for  lagging power factor load:

1.  load power factor is lagging and it is represented by cos𝞍. So draw phase current Iaph  which lags Vph by an angle 𝞍.

2. Fo is at right angle to Vph.

3. Far will be in phase with the Iaph because armature current Iaph decides armature reaction.

4. This Far has to be overcome by resultant m.m.f  Fr which is also called field m.m.f so - Far should be added to Fo vertically so that Fr counter balances armature reaction and produce rated voltage.

Phasor diagram for calculating resultant m.m.f Fr for lagging power factor load:

Expression for resultant m.m.f or field m.m.f for lagging power factor load:

From diagram,

OA =  Fo 

AB = Far

OB = Fr

From right angled triangle OCB

Far can be split into two parts 

AC = Far sin𝞍

BC = Far cos𝞍

Hence, FR can be calculated in this way.

 Calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method for lagging power factor load:

To calculate voltage regulation of synchronous machine by m.m.f method or ampere turn method draw the graph of open circuit characteristics of synchronous machine and short circuit characteristics of synchronous machine and indicate values of F0 , FAR , FR as shown below.

Graph for calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method for lagging power factor load:

Steps for calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method for lagging power factor load from graph:

1. Calculate F0 value from open circuit test on synchronous machine and mark it on x - axis. Now extend this point on to open circuit characteristics of synchronous machine curve and extend this point on y - axis which gives the value of Vph of synchronous machine.

2. Calculate FAR value from short circuit test on synchronous machine and mark it on x - axis. Now extend this point on to short circuit characteristics of synchronous machine line and extend this point on y - axis which gives the value of rated Isc of synchronous machine.

3. Now calculate FR value from the equation

 and and mark it on x - axis. Now extend this point on to open circuit characteristics of synchronous machine curve and extend this point on y - axis which gives the value of Eph of synchronous machine.

So finally we get voltage regulation of synchronous machine by m.m.f method or ampere turn method  for lagging power factor load by using below formula

Voltage regulation% = (Eph - Vph / Vph) × 100.

Hence in this way we have calculated voltage regulation of synchronous machine by m.m.f method or ampere turn method  for lagging power factor load.

Zero leading power factor:

1. If the load has zero power factor leading then the armature reaction is magnetizing in nature.

2. This will help main flux to induce rated terminal voltage.

3. So net m.m.f is less than that required to produce rated voltage.

4. So net m.m.f is algebraic difference between the two components F0 and FAR.

This can be represented as follows:

OA = F0

AB = FR

OB = FR = F0 - FAR

This shows total m.m.f is less than F0.

Steps to draw vector diagram for calculating resultant m.m.f  for  lagging power factor load:

1.  load power factor is leading and it is represented by cos𝞍. So draw phase current Iaph  which leads Vph by an angle 𝞍.

2. F0 is at right angle to Vph.

3. FAR will be in phase with the Iaph because armature current Iaph decides armature reaction.

4. FR is obtained by adding - FAR to F0.

Phasor diagram for calculating resultant m.m.f FR for leading power factor load:

Expression for resultant m.m.f or field m.m.f for leading power factor load:

From diagram,

AC = FAR sin𝞍

BC = FAR cos𝞍

OA = F0

AB = FAR

OB = FR

From right angled triangle OCB

Hence, FR can be calculated in this way.

Calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method for leading power factor load:

To calculate voltage regulation of synchronous machine by m.m.f method or ampere turn method draw the graph of open circuit characteristics of synchronous machine and short circuit characteristics of synchronous machine and indicate values of F0 , FAR , FR as shown below.

Graph for calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method for leading power factor load:

Steps for calculating voltage regulation of synchronous machine by M.M.F method or ampere turn method for leading power factor load from graph:

1. Calculate F0 value from open circuit test on synchronous machine and mark it on x - axis. Now extend this point on to open circuit characteristics of synchronous machine curve and extend this point on y - axis which gives the value of Vph of synchronous machine.

2. Calculate FAR value from short circuit test on synchronous machine and mark it on x - axis. Now extend this point on to short circuit characteristics of synchronous machine line and extend this point on y - axis which gives the value of rated Isc of synchronous machine.

3. Now calculate FR value from the equation

and and mark it on x - axis. Now extend this point on to open circuit characteristics of synchronous machine curve and extend this point on y - axis which gives the value of Eph of synchronous machine.

So finally we get voltage regulation of synchronous machine by m.m.f method or ampere turn method  for leading power factor load by using below formula.

Voltage regulation% = (Eph - Vph / Vph) × 100.

Hence in this way we have calculated voltage regulation of synchronous machine by m.m.f method or ampere turn method  for leading power factor load.

Important point to be noted while calculating voltage regulation of synchronous machine by m.m.f method or ampere turn method :

F0 is the field m.m.f required to give rated Vph when armature resistance is neglected. But if armature resistance Raph is given then F0 calculated from open circuit characteristics of synchronous machine represents excitation required to produce voltage of Vph + Iph Ra cos𝛟

Vph = rated voltage per phase.

Iaph = full load current per phase.

Ra = armature resistance per phase.

cos𝛟 = power factor of load.

Calculation of resultant m.m.f by cosine rule:

Resultant m.m.f FR can be calculated from cosine rule for both lagging and leading power factor loads.

Phasor diagrams:

by using cosine rule from triangle OAB,

In this way we can calculate Fr from cosine rule.

And hence calculate voltage regulation of synchronous machine by m.m.f method or ampere turn method  by using

Voltage regulation% = (Eph - Vph / Vph) × 100.

In this method drop due to leakage reactance is also considered as drop due to armature reaction so we get voltage regulation less than actual regulation. Hence it is called optimistic method. 

Today we have learnt how to calculate voltage regulation of synchronous machine by m.m.f method or ampere turn method . 

In the next post we are going to learn  voltage regulation of synchronous machine by zero power factor method or potier method.

You can download this post on  voltage regulation of synchronous machine by m.m.f method or ampere turn method  as PDF here.

January 03, 2017 at 06:18PM by EEE, ADBU

Voltage Regulation of Synchronous Machine (Alternator)by E.M.F Method or Synchronous Impedance Method.

Voltage Regulation Of Synchronous Machines [Alternator] By Synchronous Impedance Method or E.M.F. Method

Voltage Regulation Of Synchronous Machines [Alternator] By Synchronous Impedance Method or E.M.F. Method

Today in this post we are going to learn what is Voltage regulation of synchronous machine and different methods to calculate Voltage regulation of synchronous machine.

Definition for Voltage regulation of a synchronous machine:

Voltage Regulation of synchronous machine is defined as the difference between terminal voltage at no load and terminal voltage at full load and excitation and speed must remain same.Voltage Regulation of synchronous machine is generally calculated in percentage of full load terminal voltage.

Objectives for calculating Voltage regulation of a synchronous machine:

1. Parallel operation of alternators is affected by the voltage regulation. By calculating voltage regulation of synchronous machine we can adjust the parallel operating machines to be in synchronism.

2. Calculating voltage regulation of a synchronous machine determines the type of automatic voltage control equipment required for resisting the voltage changes.

3.When the load is thrown off voltage rise must be known because with the rise in voltage the insulation must be able to withstand this rise.

So calculation of voltage regulation of synchronous machine has a great importance.

General expression for calculating Voltage regulation of synchronous machine:

Now let us derive general expression for calculating voltage regulation of a synchronous machine

Let E be the terminal voltage of the synchronous machine at no load. Now if the synchronous machine is given full load the terminal voltage will no longer be E because of the losses so let the terminal voltage now be V.

So general expression for Voltage regulation of a synchronous machine is given by

Voltage regulation% = (E - V / V) × 100

Methods for calculating voltage regulation of synchronous machine:

There are two types of methods for calculating voltage regulation of synchronous machine.

1. Direct load test method.

2. Indirect Method.

Indirect method of calculating voltage regulation of synchronous machine can be further classified into 3 types:

1.EMF method or Synchronous impedance method.

2. MMF method or Ampere turn method.

3.Zero power factor method or potier method.

Direct load test method for calculating voltage regulation of synchronous machine by synchronous impedance method :

Now let's see how to calculate voltage regulation of synchronous machine by using direct load test method:

Circuit diagram for calculating Voltage regulation of synchronous machine by direct load test:

Circuit connections for calculating voltage regulation of synchronous machine by direct load test:

1.Firstly connections are to be made as given in the circuit diagram:

2. Armature which is star connected is connected to the three phase load with the help of TPST. TPST is a switch and it means triple pole single through. 

3. A rheostat is connected in series with the field winding. 

4. Field winding is excited by using D.C supply and flux is adjusted by adjusting the rheostat. Flux adjustment is nothing but adjust the current flow through field winding.

Procedure for calculating voltage regulation of synchronous machine by direct load test:

 1. Adjust the prime mover such that the alternator rotates at synchronous speed Ns.

 we know Eph α 𝞍 from emf equation

2. Now DC supply is given to the field winding and the current flow through field is adjusted so that the flux is adjusted such that the rated voltage is obtained at its terminals which can be seen on the voltmeter connected across the lines.

3. Now load is connected to alternator with the help of TPST switch.

4.The load is then increased such that the ammeter reads rated current. This is full load condition of alternator. Now as load is connected due to armature reaction there is loss in voltage so let the induced voltage be V. 

5.Now again adjust the rheostat of the field winding to get rated voltage at alternator terminals.

6.Now remove the load by opening TPST switch and the excitation , speed should not be changed it should be same as before removing the load.

7. As there is no load there is no armature reaction the induced emf is equal to terminal voltage which is E.  

Now we can calculate voltage regulation of synchronous machine by 

Voltage regulation% =( E - V / V) × 100 at a specific power factor.

Limitations for calculating voltage regulation of synchronous machine by using direct load method:

This method is applicable only for small capacity machines for larger capacity machines it is not economical because that much load cannot be given directly.

In this way we have calculated the voltage regulation of synchronous machine by direct load test method.

For larger capacity machines voltage regulation can be calculated by Indirect method.

In the next post we can see how to calculate voltage regulation of synchronous machine by Indirect method.

You can download PDF form of Voltage Regulation Of Synchronous Machines [Alternator] By Synchronous Impedance Method or E.M.F. Method .

Related Topics;

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January 02, 2017 at 05:50PM by EEE, ADBU

Voltage Regulation of Transformer

Voltage Regulation Of Transformer

Hello everyone,
In this post we are going to discuss about Voltage regulation of a transformer.

Read here : Differences Between Core And Shell Type Transformers

What is meant my Voltage regulation of transformer?

Voltage regulation of a transformer may be defined as the difference between no load voltage of the secondary terminal of a transformer and full load voltage of the secondary terminal of that transformer at a certain power factor. Voltage regulation of a transformer is expressed in percentage of either no load secondary terminal voltage or full load secondary terminal voltage.

Read here : EMF Equation of Transformer & Voltage Transformation Ratio

Objective to calculate voltage regulation of transformer:

Calculating voltage regulation of transformer gives how much efficiently the transformer is resisting the voltage changes from no load to full load. If there is no change in value of secondary voltage from no load to full load then the transformer is ideal and has voltage regulation 0%. So the lower the value of voltage regulation the higher is the performance of the transformer. 

 Procedure to calculate voltage regulation of transformer:

Consider a transformer which is at no load which means the secondary of the transformer is open circuited. In this case the secondary voltage of the transformer and induced emf are same let it be E₂ . Now full load is connected to the secondary of a transformer. In this case current I₂ passes in the secondary which will lead to voltage drop and is given by I₂Z₂. Where Z₂ is called secondary impedance of transformer. During this situation primary winding will draw equivalent full load current. Because of the voltage drop the secondary voltage cannot be E₂ anymore so secondary induced emf will be V₂.

Equivalent circuit for calculating voltage regulation of transformer:

Equation for calculating voltage regulation of a transformer:

Voltage regulation of transformer in percentage can be represented as:

Voltage regulation % = (E₂-V₂/V₂)×100%. This is called regulation down. Power factor is specific.

Calculating voltage regulation of transformer for lagging power factor:

Now lets derive the expression for calculating voltage regulation of transformer for lagging power factor.

Phasor diagram:

here cos𝚹₂ is lagging power factor

From diagram,

                       OC = OA + AB + BC

                       

                       OA = V₂

                       

                       AB = AEcos𝚹₂ =  I₂R₂cos𝚹₂

          

                       BC=DEsin𝚹₂=I₂R₂sin𝚹₂

Angle between OC and OD is very less so OC is approximately equal to OD.

                 E₂ = OC = OA + AB + BC.

                 E₂ = OC = V₂ + I₂R₂cos𝚹₂ + I₂R₂sin𝚹₂

Now voltage regulation of transformer at lagging power factor is,

Voltage regulation% = (E₂-V₂/V₂) × 100%

Voltage regulation%=( I₂R₂cos𝚹₂+ I₂R₂sin𝚹₂/ V₂ ) ×100%.

Calculating voltage regulation of transformer for leading power factor:

Now lets derive the expression for calculating voltage regulation of transformer for leading power factor.

Phasor diagram:

here cos𝚹₂ is leading power factor

From diagram,

                         OC = OA + AB - BC

                          OA = V₂

                       

                         AB = AEcos𝚹₂ = I₂R₂cos𝚹₂

          

                         BC = DEsin𝚹₂ = I₂R₂sin𝚹₂  

Angle between OC and OD is very less so OC is approximately equal to OD.

                         E₂  = OC = OA +AB - BC.

                          E₂ = OC = V₂ + I₂R₂cos𝚹₂ - I₂R₂sin𝚹₂

Now voltage regulation of transformer at leading power factor is,

Voltage regulation% = (E₂-V₂/V₂) × 100%

Voltage regulation%=(I₂ R₂cos𝚹₂ - I₂R₂sin𝚹₂ /V₂ ) ×100%.

Thus we have learnt what is voltage regulation of transformer and derived expressions for voltage regulation of transformer for lagging and leading power factors. 

You can download this article of Voltage Regulation OF Transformer as a PDF here.

January 01, 2017 at 11:01PM by EEE, ADBU

Type of Light Bulb base & Socket:Part-1

Introduction:

• Generally we do not aware about which type of socket we need for light Bulb. This is very important while buying a bulb, with the wrong base selection will not fit in the lamp or fixture
• Light bulb bases and sockets are normally defined by a letter-number-letter format, with the last letter optional.
• The first letter designates the shape or form of the base, the numbers represent either the width of the base or the distance between the pins.
• The second letter designates the number of pins or contacts on the lamp.
• The numbers are normally in millimeters. LED light bulb sockets and bases are manufactured to the same standards as halogen, incandescent and other traditional lights.

Type of Sockets:

There are different types of Socket available in market

1. Bayonet Cap Base (B)
2. Edison Screw Cap Base (E)
3. Single Pin Type Base (F)
4. Bi Pin or Multi Pin Type (G)
5. Cable Connections (K)
6. Pre-focused Light Base (P)
7. Recessed Contact(s) Base (R)
8. Shell-type Light Bulb Base (S)
9. Telephone Slide Base (T)
10. Wedge Base
11. Special Type Light bulb Base (X)

(1)  Bayonet Cap (B / BC / SBC):

• Type of Connection: “push and twist” action
• Pin Configuration: (Bxx or BCxx):
• The First letter indicates the shape or Style of the base.
• The Second number indicates the width of the base (normally in millimeters).
• Example:
• The “B” refers to the style of Base which is a Bayonet, and the 22 means it has a 22 mm base width.
• Application: All Regular type of Bulbs including specialist low voltage halogen lamps

(2) Edison Screw Cap (E / ES):

• Named as inventor Thomas Edison, the Edison Screw or “ES” lamp fitting is used in a vast range of applications.

• Type of Connection: “Screw” Action
• Pin Configuration: (Exx or ESxx):
• The First letter indicates the shape or Style of the base.
• The Second number indicates the width of the base (normally in millimeters).
• Example: E26 base.
• The “E” refers to the style which is an Edison screw-in, and the 26 means it has a 26 mm base width.
• Application: Large chandeliers Some Decorative Lamps.
• The most commonly used screw fittings are shown in the table below. Other, less frequently used, sizes include E11, E17 and E26.

Designation	Diameter	Name	Abbreviation
E5	5mm	Lilliput Edison Screw	LES
E10	10mm	Miniature Edison Screw	MES
E12	12mm	Candelabra Edison Screw	CES
E14	14mm	Small Edison Screw	SES
E17	17mm	Intermediate Edison Screw Base	IES
E27	27mm	Medium Edison Screw	ES
E39	39mm	Mogul or Giant Edison Screw Base	GES
E40	40mm	Giant Edison Screw	GES

(3) Bi Pin or Multiple Pin Type Base (G)

• The “G” type of lamp base is used to as a “pinned” base. This may be several Numbers of different Types of pins.
• Type of Connection: “Pin” Type
• Pin Configuration: (G(U,X,Y,Z) -xx-x-x):
• It is indicate by Letter (or Letters)-Numbers-Optional letter- Letter:
• The first letters includes “G” which is followed by a Second (optional Letter) Letter U, X, Y or Z.
• The second letter (U, X, Y,Z) represents the configuration of the base, which determines the diameter and shape of the pins. For example, pins may be rounded, square, grooved, fat or slender.
• Without any Optional Letter = Base length is 8.25mm and Pin Diameter is 0.7mm
• For Y=Base length is >6mm and Pin Diameter is 0.7mm
• For X= Base length is <7.5mm and Pin Diameter is 1mm
• For U= Base length is >6mm and Pin Diameter is 1mm With One or Two Grip channel.
• For Z=P Base length is >6mm and Pin Diameter is 1mm without Grip Channel.
• The Third number indicates the Distance in millimeters between the centers of each pin.
• The Forth (optional Letter) Letter indicate the number of pins, no letter means 2 pins. d for double Pin ,s for Single pin, t for Triple pin or 3 pins and q for Quadruple pin or 4 pins.
• The Fifth Letter indicates position of Dowel (Slot) in Socket
• Examples: GU10 base type, GU24q 2Pin base type, G13d 3pin.
• For GU24q 2 Socket, U=Pin length is>6mm with diameter 1mm with Grip channel, No of Pin is 4 no’s and Dowel is on Left Side
• Application: Halogen, Compact Fluorescent ,LED Types Bulbs

 

Difference between G24q-1, G24q-2, G24q-3 Type Socket

• Here G=Type/ Shape of Socket
• 24=Distance between each Pin
• q= Quadruple (Four) Pin.
• 1=Indicate Dowel (Slot) Position ,1=Middle, 2=Left, 3=Right Position

Difference between Gx24, G24 Type Socket

• In Gx24 The Base is smaller while in G24 Base is larger.

Type	Pin to pin distance	Pin Diameter	Typical Bulbs that use this base
G4	4mm	0.65-0.75mm	MR11 and other small halogens of 5/10/20 watt and 6/12 volt
GU4	4mm	0.95-1.05mm
GY4	4mm	0.65-0.75mm
GZ4	4mm	0.95-1.05mm
G5	5mm		T4 and T5 fluorescent tubes
G5.3 GU5.3 GX5.3 GY5.3	5.33 mm	1.47-1.65mm	MR16 and other small bulbs typically using 12/24 volts
G6.35 GX6.35 GY6.35	6.35 mm	0.95-1.3mm
G8	8mm
G9	9mm
GU10	10mm		bulbs using twist-lock bi-pin base
G13	12.7mm		T8,T10 & T12 fluorescent tubes
G23	23mm	2mm
GU24	24mm		2 and 4 pin bases with center key
GX53	53mm		used with puck shaped lamps typically twist-lock

January 01, 2017 at 10:00AM