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ENGINEERING COLLEGE BIKANER 2009-10 SUMMER TRANING REPORT SAFETY EVALUATION OF AUDIO/VISUAL AND IT PRODUCTS at ELECTRONICS REGIONAL TEST LABORATORY (WEST), MUMBAI Submitted in partial fulfillment of the requirement for the degree of BACHELOR OF TECHNOLOGY IN ELECTRONICS AND COMMUNICATION OF RAJASTHAN TECHNICAL UNIVERSITY, KOTA Submitted to: Submitted By: 1

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Page 1: Safety Lab Training

ENGINEERING COLLEGE BIKANER

2009-10

SUMMER TRANING REPORT

SAFETY EVALUATION OF AUDIO/VISUAL AND IT PRODUCTSat

ELECTRONICS REGIONAL TEST LABORATORY (WEST), MUMBAI

Submitted in partial fulfillment of the requirement for the degree of

BACHELOR OF TECHNOLOGYIN

ELECTRONICS AND COMMUNICATIONOF

RAJASTHAN TECHNICAL UNIVERSITY, KOTA

Submitted to: Submitted By:

Mr. M.L. Meena Vinita Bhalla

Assistant professor IV Year

ECB (ECE, ECB)

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Acknowledgement

The satisfaction and euphoria that accompany the successful completion of any

task would be but incomplete without the mention of the people who made it

possible, whose constants guidance and encouragement crowned my efforts with

success.

I consider it my privilege to express my gratitude and thanks to following persons

for their help, encouragement and intellectual influence during the course of the

summer training.

I convey thanks to my guide Shri. Dhanroopmal, additional director, Shri.

Shrikant Dingore, scientific officer ’SB’ for their invaluable guidance

throughout the entire training.

I express our sincere gratitude to Shri. P.K.Srivastav (director, ERTL), for

providing me with the necessary facilities. Last but not least, we are greatly

indebted to my parents, lectures and friends for standing by us throughout the

training.

VINITA BHALLA

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PREFACE

An engineer is a person who applies the knowledge of science for the welfare of society. Teaching technical studies can’t be perfect without project work. Hence, the project work is great valuable for the engineering students. This report contains basic knowledge of safety lab, which includes why safety testing of appliances is necessary.

The scientists working in safety lab are trained and certified by National / International Institutes in their respective work areas. Facilities at safety lab are augmented every year keeping in view the regional industry requirements and technological transitions

This safety-testing lab is designed to test and protect user from six potential hazards such as shock, fire, energy, injury, radiation and chemical. Equipment is tested thoroughly by all the means such as power input/output measurement, temperature rise measurement, insulation resistance measurement, electric strength measurement, fault condition measurement, clearance & creepage distance measurement, leakage current measurement, touch current measurement, abnormal test, mechanical strength measurement, supply connection and external flexible cords measurement, etc.

Test Laboratories provide feedback on design of the product in order to improve products to meet safety standards. Safety investigation of products for hazards like Electric shock, energy, fire, radiation, personal injury etc., can be done with the help of Jigs and Fixtures developed by the Laboratory.

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1.Introduction:

Electronics regional test laboratory (WEST), was setup under standardization, testing & quality certification (STQC) directorate, department of information technology, Govt. of India, in the year 1985 as one of the national institutes to fulfill the needs of Indian industries with regard to test, calibration, training & quality improvement services. The laboratory situated at MIDC industrial area, Andheri (E) is well equipped with state of –art-facilities, dedicated, professionally qualified & trained scientists/engineers.

The quality system of laboratory complies with international standard- ISO/IEC- 17025:2005 and has received number of national and international accreditations.

The laboratory services have enabled customers to improve their product quality and reliability which enhanced their domestic and export market share. Client range varies from typical small-scale industries to MNCs.

Their mission is to facilitate improvement of quality and reliability of Indian electronics & information technology products so as to enhance their acceptability in the domestic and international markets.

Upgraded testing facilities are provided to industries in compliance with global standards and requirements.

2.SERVICES AT A GLANCE:

2.1 Testing: Components, sub-systems, equipment & systems Environmental / reliability Electromagnetic compatibility (EMC) Safety

2.2 Calibration:

Electrical & electronic (electro-technical) parameters

DC/AC Voltage DC/AC current DC/AC resistance Inductance, capacitance Frequency RF power & level Power/ energy PT/CT Ratio Optical power

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2.3 Non-electrical parameters:

Temperature Humidity Pressure Dimension Mass Torque Volume Calibration services In-house & On-site

2.4 Certification:

ISO 9000 QMS Registration Safety certification (‘S‘ MARK) EMI / EMC Certification (‘ EMC‘ Mark) Environmental management system certification (ISO 14000) Performance Assessment scheme (IEC standards)

3.TESTING:

3.1 Electronic Components:

Components are building blocks of any system/equipment/product. ERTL has comprehensive testing facilities for testing electrical, electronics, & electromechanical components accredited by NABL and recognized by BIS.

Active & passive components1. Resistor2. Inductor3. Capacitor4. Transistors5. Ics

Electromechanical components1. Switches2. Cable & wires3. Fuse & fuse holders4. Plugs & sockets5. Appliance coupler6. Circuit breaker

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Insulator material testing1. Surface & volume resistivity2. Dielectric constant3. Glow wire test4. Flammability5. High voltage test6. Ball pressure test

Battery test1. Capacity test2. Storage test3. Initial life test4. Leakage5. Endurance

3.2 Equipment & sub-system testing:

Major category of product tested is:

Static & electro magnetic- single and 3 phase energy meters Electronic ballasts Luminaries

3.3Environmental/reliability testing:

This lab checks the performance of products at varying environmental conditions. It has testing facility which functions round the clock. The environmental facilities in ERTL(W) simulate the following:

High temperature Low temperature Corrosion Low air pressure

Lab has following facilities for durability testing:

Vibration (both sine wave & random) Impact- resistive & non-repetitive Bump Shock

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Climate1. Dry heat test2. Damp test3. Cold test4. Thermal shock

Mechanical durability capability1. Bump2. Vibration3. Mechanical shock4. Acceleration5. Drop, toppling & freefall

3.4 Compliance testing: EMC testing

Electro magnetic compatibility addresses emission and immunity phenomenon of devices and systems.It is classified into:

1. Conducted emission 2. Radiated emission3. Conducted Immunity4. Radiated Immunity

Safety testing (equipment)

Product is said to be safe if it is designed to protect user from six potential hazards such as shock, fire, energy, injury, radiation and chemical.

3.5 Services offered:

» TMI Safety » Power/Energy Safety » IT Safety » Critical Component » Medical » Consumer/ Household

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4.Principles of safety:

Safety testing is essential so that safe apparatus can be designed and manufactured.

4.1 Hazards:

Safety testing is done to prevent injury or damage due to the following hazards:

Electric shock Excessive temperatures Radiation Implosion Mechanical hazards Fire

4.2 Electric shock:

Electric shock is due to current passing through the human body. Currents of the order of a milliampere can cause a reaction in persons in

good health. To provide protection against the possibility of higher voltages appearing

on parts, which may be touched or handled, such parts are either earthed or adequately insulated.

For parts, which can be touched, two levels of protection are provided. Thus a single fault and any consequential faults will not create a hazard. The provision of additional protective measures, such as supplementary insulation or protective earthing, are not considered a substitute for, or a relief from, properly designed basic insulation.

CAUSE PREVENTION

Contacts with parts normally at hazardous VOLTAGE

Prevent access to parts at hazardous voltage By fixed or locked covers, interlocks, and etc. discharge capacitor at hazardous voltage.

Breakdown of insulation between partsNormally at hazardous voltage andAccessible parts.

Use double or reinforced insulationBetween parts normally at hazardous voltages and accessible parts so that Breakdown is not likely to occur.

Connect accessible conductive

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parts to protective earth so that the voltage, which develops, is limited to a safe value.

The insulations shall have adequate mechanical and electrical strength.

Breakdown of insulation between parts normally at hazardous voltage and circuits normally at non-hazardous voltages, therebyPutting accessible parts and terminals at hazardous voltage.

Segregate hazardous and non-hazardousVoltage circuits either by double or reinforced insulation so that breakdown is not likely to occur, or by a protective earthed screen, or connects the circuit normally at non-hazardous voltage to protective earth, so that the voltage which can develop is limited to a safe value.

Touch current from parts at hazardous voltage through the human body.(Touch current can include current due to RFI filter components connected between mains supply circuits and accessible parts orTerminals.)

Limit touch current to a safe value or provideA protective earthing connection to theAccessible parts

4.3 Excessive temperatures:

Prevent injury due to excessive temperatures of accessible parts Prevent damaging of insulation due to excessive internal temperatures Prevent mechanical instability due to excessive temperatures developed

inside the apparatus.

4.4 Radiation: Prevent injury due to excessive energy levels of ionizing and Laser

radiation. For example: - by limiting the radiation to non-hazardous values.

Implosion To prevent injury due to implosion of picture tubes.

4.5 Mechanical hazards:

Avoid presence of sharp edges Provide guarding or interlocking of dangerous moving parts.

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4.6 Fire:

Fire can result from: - Overloads Component failure Insulation breakdown Bad connections Arcing

The following preventive measures are recommended: -

Use of suitable components and subassemblies; Avoidance of excessive temperatures which might cause ignition under

normal or fault conditions; Use of measures to eliminate potential ignition sources such as

inadequate contacts, bad connections, interruptions; Limitation of the quantity of combustible material used; Control of the position of combustible materials in relation to potential

ignition sources; Use of materials with high resistance to fire in the vicinity of potential

ignition sources; Use of encapsulation or barriers to limit the spread of fire within the

apparatus; Use of suitable fire retardant materials for the enclosure.

5. General requirement:

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Rated voltage<=250 for single phase appliances Others up to 480 volts

5.1 General terms: RMS voltage and current Rated voltage: - specified by manufacturer Rated voltage range: - specified limits by manufacturer Working voltage: - at working/ maximum applied voltage Rated power input Rated power range Rated current Rated frequency Rated frequency range Normal operation: - appliance operated in normal use, when connected to

supply mains. Rated impulse voltage: - withstand capability of its insulation against

transient over voltages Dangerous malfunction: - unintended operation of appliances that may

impair safety

5.1.1 Cords:

o Detachable cord: - flexible cord, intended to be connected to appliances by suitable appliance coupler

o Interconnection cord: - external flexible cord not connected to mains

o Supply cord: - fixed cord, fixed to applianceo Type X attachment: - easily replacedo Type Y attachment: - not easily replaced; available only from

manufacturero Type Z attachment: - supply cord can’t be replaced without

breaking or destroying appliances.

5.1.2 Supply leads: set of wires, connecting appliance to fixed wiring

5.1.3 Insulation:o Basic: - applied to live parts to provide basic protection against

electrical shocko Supplementary: - provided in addition to basic; in case basic

fails, to provide protection against electric shocko Double: - basic + supplementary

o Reinforced: - single insulation, equivalent to double insulation

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o Functional: - insulation between conductive parts of different potential

o Protective: - impedance connected between live parts and accessible conductive parts of class II construction; so in case of fault/ normal condition; current limited to safe value

Protective impedance

5.1.4 Appliances:

o Class 0 appliances: - appliances in which electric shocks relies only on BI

o Class 01 appliance: - at least BI, throughout, earthing terminal incorporated, supply cord without earthing conductor and plug without earthing contact

o Class 1: - BI+ conductive accessible parts connected to protective earthing conductor in such a way conductive accessible parts are not live in case of BI failure

o Class II: - BI+DI/RI. No provision for protective earthing

o Class 1/01 = DI/RI +provision for earthing

o Class II construction: - parts of appliance for insulation depends on DI/RI

o Class III appliances: - protection against electric shock relies on supply at safety extra-low voltage

o Class III construction: - part of appliances protection against electric shock relies on supply at safety extra-low voltage

Clearance: - shortest distance in air between conductive part or conductive parts and accessible surface

Creepage distance: - shortest distance between surface of insulation between two conductive parts or between conductive parts and accessible surface

5.1.5 Voltage:

o Extra low voltage: - when appliances supplied at rated voltage; source inside appliance supplied voltage between conductors or between conductors and earth which doesn’t exceed 50V

o Safety extra-low voltage (SELV): - V<42V between conductor and conductor and earth

o SELV: - mains coming from safety transformer/ converter with separate windings

5.2 Safety isolating transformer:

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Transformer input windings are separated from output windings by double insulation or reinforced insulation.

5.3 Protective extra low voltage circuit:

Earthed circuit operating at SELV, which is separated from other circuits by basic insulation, double insulation, reinforced insulation and protective screening.

*Protective screening is separation of circuits from other live parts by means of earthed screen.

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6. PRACTICAL APPLICATIONS:

6.1 Clearance And Creepage Measurement Of Split Bobbin Power Transformer:

Figure 6.1 : Transformer

6.1.1 Creepage Distance:

Creepage is the shortest path between two conductive parts (or between a conductive part and the bounding surface of the equipment) measured along the surface of the insulation. A proper and adequate creepage distance protects against tracking, a process that produces a partially conducting path of localized deterioration on the surface of an insulating material as a result of the electric discharges on or close to an insulation surface. The degree of tracking required depends on two major factors: the comparative tracking index (CTI) of the material and the degree of pollution in the environment. Used for electrical insulating materials, the CTI provides a numerical value of the voltage that will cause failure by tracking during standard testing. IEC 112

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provides a fuller explanation of tracking and CTI.1 Tracking that damages the insulating material normally occurs because of one or more of the following reasons:

1.Humidityin the atmosphere 2.Presence of contamination

3.Corrosive chemicals 4.Altitude at which equipment is to be operated

6.1.2 Clearance Distance:

Clearance is the shortest distance between two conductive parts (or between a conductive part and the bounding surface of the equipment) measured through air. Clearance distance helps prevent dielectric breakdown between electrodes caused by the ionization of air. The dielectric breakdown level is further influenced by relative humidity, temperature, and degree of pollution in the environment.

Figure 6.1.2 Split Bobbin

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7 layers of insulation(10mm)

4 layers of insulation(10mm)

Secondary windings(22V)

1 layers of insulation (40mm)

1 layers of insulation (40mm)

(0V)

Primary windings(230V)

(210V)

(220V)

Core

sleeve

3 layers of insulation(15 micron)

Figure 6.1.3 Cross-sectional view of split bobbin transformer

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Measurement DistanceClearanceCreepage

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7. Power measurement test of mixer/Amplifier:

7.1 Plena Mixer Amplifiers:

The Plena mixer amplifier is a versatile, high-performance Unit with four mono microphone inputs and a music input. It fulfills a wide variety of public address requirements at a surprisingly low cost.

7.2 Functions:

All input channels have a phantom power supply to provide power to condenser microphones and selectable speech filters for improved intelligibility. Input channels 3 and 4 can also be switched to line sensitivity. Separate music inputsAre available with their own input selector and volume control. Input channel 1 can take priority over all other microphone and music inputs. Contact closure on the 5-pin DIN connector, or if the signal level on channel 1 exceeds a predefined value (VOX) will activate priority. A 2-tone chime can be configured to precede a priority announcement. A telephone or emergency input with VOX activation and itsOwn preset volume control overrides all other input. Loop through input and output connections enable external sound processing equipment, such as an equalizer or thePlena feedback suppressor, to be connected between the preamplifier and

the power amplifier stages. An LED VUmeter monitors the master output. The unit also has a tape output channel.The Plena mixer

amplifiers come in a range of Figure 7.2 Plena feedback suppressor

maximum output power. This power is directly available on 70 V and 100 V constant voltage connections and on a low Impedance connection for an 8-ohm load. Moreover, the amplifiers have a separate 70 V / 100 V call-only output channel for addressing areas where only priorityAnnouncements are required, and a 70 V / 100 V mix-only output channel for areas where no priority announcements should be heard. The call-only

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output can also be used for 3-wire remote, volume control override. For more output power than the built-in power stage can deliver, additional Plena power amplifiers can be connected to the balanced line output in a loop-through arrangement. The LBB 1914/10 offers the same functionality as the LBB 1912/10 but also has two front-panel switches to direct the amplifier output to two separate zones. This is useful when certain announcements or background music should not be heard in part of a building. Priority calls, however, are always routed to both zones.

7.2.1 Controls and indicators :

Front• LED power meter• Power on LED• Master volume control knob• Four volume control knobs for mic inputs• Three knobs for BGM volume, treble, and bass levels• BGM source selection knob• On/off switch• Two zone selection buttons (LBB1914/10 only)

Back• EMG input volume control• Two mic/line switches• Chime on/off switch• Mains voltage switch

7.2.2 Interconnections:

Front• Headphone jack

Back• Priority mic input (DIN/6.3 mm jack)• Mic input (XLR/6.3 mm jack)• Two mic/line inputs (XLR/6.3 mm jack)• Three audio inputs (2 x cinches)• EMG input (screw)• Line output (XLR)• Tape output (2 x cinches)• Insertion input/output (2 x cinches)• 24 VDC input• Three (five for the LBB 1914/10) loudspeaker outputs (Screw)

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Functional generator

AC Power sourceDC power meter

Rear panel of mixer/amplifierLoad(83Ω)

Figure 7.3.1 Block diagram of Power measurement test

7.3 Power measurement test:

If appliance is marked with rated power input, power at normal operating temperature shall not deviate from rated power input by more than following deviation: -

Power input: -

Type of applianceRated power Deviation

All appliance <=25 20%Heating appliance & combined appliance

>25 & <=200 ±10%

>200 5%

Motor-operated appliance>25 & <=300 20%

>300 50%

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1 2 3 4 5 6 7 8

100

v

70V 0V

24

VD

C IN~ 0 ~

Vrms

Irms

~~~~

Freq.

V A

AC power sourceDC power meterFunctional generator

Rear panel of amplifier

Figure 7.3.2 Block diagram of Power measurement test

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1 2 3 4 5 6 7 8

100

v

70V 0V

24

VD

C IN~ 0 ~

Vrms

Irms

~~~~

Freq.

V A

AC power sourceDC power meterFunctional generator

Rear panel of amplifier

Figure 7.3.3 Block diagram of Power measurement test (Load= 83Ω)

Load=83Ω

Power measurement test at load = 83Ω (AE120W, 83E±5%)

Voltage (V) Frequency (Hz) Current (A) Power (kW) Power Factor

207 50 1.34 0.257 0.78

230 50 1.73 0.31 0.77

253 50 1.76 0.37 0.78

207 60 1.53 0.362 0.74

230 60 1.62 0.306 0.74

253 60 1.59 0.328 0.78

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1 2 3 4 5 6 7 8

100

v

70V 0V

24

VD

C IN~ 0 ~

Vrms

Irms

~~~~

Freq.

V A

AC power sourceDC power meterFunctional generator

Rear panel of amplifier

Figure 7.3.4 Block diagram of Power measurement test (load=8Ω)

Load =8Ω

Power measurement test at load = 8Ω (AE250WW, 8E±5%)

Voltage (V)Frequency (Hz)

Current (A)

Power (kW) Power Factor

207 50 1.79 0.311 0.836

230 50 1.97 0.378 0.8306

253 50 2.07 0.4397 0.8278

207 60 1.8 0.313 0.8377

230 60 1.98 0.379 0.8326

253 60 2.08 0.433 0.8285

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l

1 2 3 4 5 6 7 8

100

v

70V 0V

24

VD

C IN~ 0 ~

Vrms

Irms

~~~~

Freq.

V A

AC power sourceDC power meterFunctional generator

Rear panel of amplifier

Figure 7.3.5 Block diagram of Power measurement test (load 4Ω )

Load=4 Ω

Power measurement test at load = 4Ω (AE250W, 4E±5%)

Voltage (V)Frequency (Hz)

Current (A)

Power (kW) Power Factor

207 50 0.31 0.045 0.62

230 50 0.32 0.04 0.61

253 50 0.33 0.04 0.61

207 60 0.31 0.04 0.62

230 60 0.32 0.04 0.61

253 60 0.32 0.05 0.61

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1 2 3 4 5 6 7 8

100

v

70V 0V

24

VD

C IN~ 0 ~

Vrms

Irms

~~~~

Freq.

V A

AC power sourceDC power meterFunctional generator

Rear panel of amplifier

Figure 7.3.6 Block diagram of Power measurement test (load =44Ω)

7.4 Conclusion:

All the parameters mentioned by manufacturer are correct and in limit.

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1

2

3

4 5

6

7

8

910

8.Temperature Rise Measurement using K-Type thermocouple:

Temperature rise other than windings are determined by Fine-wire thermocouple positioned so that they have minimum effect on temperature of part under test.Temperature rises of electrical insulation; other than that of windings; is determined on surface of insulation at places where failure could cause

Short Circuit Contact between live parts and accessible parts Bridging of insulation Reduction of clearance distance / creepage distance.

Temperature rise of windings are determined by RESISTANCE METHOD; in case of non-uniform, temperature rise by means of thermocouple

Δt = ((R2-R1)/R1)(k+T1)-(T2-T1)

Figure 8.1 K-type Thermocouple

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A

Output

transformer

SMPS heat sink

R186

Mai

n tra

nsfo

rmer

Outputconnector

Interface PCB

PCB

Figure 8.2 Temp. rise measurement

9.Abnormal test of amplifier/ mixer:

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Sr.No. ThermocoupleTemp (after 20mins)(°C)

Temp (after 20mins)(°C)

1 Ambient at 230V26.3 27.3

2 Heat sink 65.1 66.1

3 O/p Transformer61.8 62.8

4 SMPS heat sink 78.9 79.9

5 R186 85.5 86.5

6Main transformer 105.3 106.3

7 O/p connector 52.4 53.4

8Appliance coupler 44.2 45.2

9 PCB 56.1 57.1

10 PCB interface 32.1 33.1

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1

2,3

4

5

1. Secondary is short-circuited, when output is short circuited; power switch dB goes off.2. When fan is blocked, it takes 7-8 mins to heat up and then automatically power switch dB goes off. This is due to inbuilt thermistor.3. When fan is unblocked, it takes 3-4 mins to get started.4. When output of rectifier circuit is short circuited, fuse is blown. This is because current flowing through circuit is high.5. When full loading of main transformer is done, trip after two hours.

Figure 9.1 Amplifier

Δt = ((R2-R1)/R1)(k+T1)-(T2-T1)

Initial resistance of primary windings =7.705ΩInitial resistance of secondary windings=117.69mΩFinal resistance of primary windings =9.9ΩFinal resistance of secondary windings =162mΩ

Δt = 74.5°C

10.Power measurement test and abnormal test of Torodial transformer:

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10.1 Toroidal Transformer:

Doughnut shaped toroidal transformers are used to save space compared to EI cores, and sometimes to reduce external magnetic field. These use a ring shaped core, copper windings wrapped round this ring (and thus threaded through the ring during winding), and tape for insulation.

Fig. 10.1 Toroidal Transformer

10.2 Toroidal transformers compared to EI core transformers:

Lower external magnetic field Smaller for a given power rating Higher cost in most cases, as winding requires more complex and slower

equipment Less robust Central fixing is either

o bolt, large metal washers and rubber pads o bolt and potting resin

Over-tightening the central fixing bolt may short the windings

Greater inrush current at switch on-

Fig. 10.2.1 Power Measurement test of main Transformer

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2layers of insulationSleeve

2layers of insulation

Blue (19.4V (S))

Black (0V(S))

2layers of insulation

Red (14.55 V(S)) Gray (0V(S))

2layers of insulation

1layers of insulation

4layers of insulation

Orange (70 V (P))

Red (100 V (P))

Brown (31 V(P))

Gray (22 V(P))

Black (0 V(P))

Red (14.55V(S)) Orange (14.55 V (S))Gray (0 V (S))

CORE

Figure 10.2.2 Cross-sectional view of torodial transformer

Secondary ----[Red (100V), orange (70V), Brown (31V), Gray (22V), black (0V)]

Primary---- [orange (14.55V), gray (0V), red (14.55V), black (0V), blue (19.4V)]

11. Proficiency testing of Switched mode power supply

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11.1 SMPS:

Switched-mode power supply (switching-mode power supply/SMPS, or simply switcher) is an electronic power supply unit (PSU) that incorporates a switching regulator in order to provide the required output voltage. A SMPS is a power converter that transmits power from a source to a load. The function of the converter is to provide a regulated output voltage usually at a different level from the input voltage.Unlike a linear power supply, the pass transistor of a switching mode supply switches very quickly (typically between 50 kHz and 1 MHz) between full-on and full-off states, which minimizes wasted energy. Voltage regulation is provided by varying the ratio of on to off time. In contrast, a linear power supply must dissipate the excess voltage to regulate the output. This higher efficiency is the chief advantage of a switch-mode power supply.Switching regulators are used as replacements for the linear regulators when higher efficiency, smaller size or lighter weight are required. They are, however, more complicated, their switching currents can cause electrical noise problems if not carefully suppressed, and simple designs may have a poor power factor.

11.2 Theory of operation:

Figure 11.2 Block diagram of a mains operated AC–DC SMPS with output voltage regulation

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time ambient transformer capacitor dry temp. wet temp humidity12:00 29.6 36.7 36.7 28 22 4212:30 29.4 69.3 58.1 27 22 5013:00 29.3 75.6 62 28 22 4213:30 29.1 77.1 62.8 28 22 4214:00 29.2 77.4 62.8 28 22 4214:30 29.2 77.6 63.1 28 22 4215:00 29.2 77.1 63.5 28 22 4215:30 29.1 77.7 63.5 28 22 4216:00 29.2 77.6 63 28 22 4216:30 29.2 77.8 63.1 28 22 42

Figure 11.3 TEMPERATURE RISE MEASUREMENT (USING THERMOCOUPLE)

Input =100/120 V AC, 3.2 A(88V-132V AC), 50/60Hz

Figure 11.4 Complete setup of SMPS temperature rise measurement

Bibliography

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International electro technical commission Household & similar electrical appliance-safety, ISIEC 60335

International electro technical commission Audio/video electrical appliance-safety, ISIEC 60065 www.Wikipedia.org

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