Analysis of Lighting Circuits and their Practical Applications

Analyse the Types of Lighting Circuits Available in the Industry by Assessing Their Practical Applications

Summary

The three lighting system chosen and researched where incandescence, fluorescent and metal halide.  The application environment chosen was the warehouse with LED’s being the most suitable option for the chosen environment.

Section 1 Introduction

1.1  Introduction

The plant requires additional lighting systems due to increase employee growth.  The plant requires various lighting options due to various applications around the plant.  I have been employed to construct a written report of suitable options.

1.2  Aim

My aim is to ascertain variable options for additional lighting systems as well as a suitable lighting system for a chosen application environment.

1.3  Objectives

1.3.1  Research

         Research variable lighting system options for suitable use.  Its construction, characteristics and efficiency.

         Suggest suitable lighting system option for a chosen application environment, listing advantages and disadvantages of this option

Section 2 Lighting

2.1  Lighting

See Appendix A for types of lighting systems.

2.1.1 Light Emissions

Energy is transferred and absorbed by the electrons, elevating them to a higher energy levels.  Elevated higher energy electron are temporary.  Elevation is not stable and electrons descend back to their original levels.  During elevation, electron absorb energy and release surplus energy as photos well it descends. 

Dependent on quantity of energy absorbed electrons elevate to different higher orbitals and have different surplus of energy.  The energy released generate electromagnetic radiation, composing of various wavelengths (visible range – light energy, infra-red range – thermal energy).

There are two main types of lighting Incandescent and luminescent.

2.1.2 Incandescent

Principle

The emission of electromagnetic radiation from a substance (filament) when excited by heating source (thermal energy). 

2.1.3 Luminescent

Principle

The Emission of electromagnetic radiation when substance (atoms) is excited by the transfer of energy from a non-heating source (electrical current, chemical reaction).

2.2  Types of Lighting Systems (Incandescent)

2.2.1 Incandescent

Construction

A outer glass bulb housing a stem (glass or ceramic) within, fixed onto the base of the bulb on the cap. Cap is seal onto the bulb (fixed onto the based creating air tight seal).  An Inert gas or vacuum is present between the glass bulb and the stem.  The cap is heated-cured/fused onto the outer bulb providing air tight seal. 

The vacuum/inert gas acts as insulator.  The Inert gas/vacuum separates and contains the filament, preventing the filament oxidation (evaporation) from surrounding conditions (oxygen/air flow).  The absences of convection currents allows high filament temperature and illumination. 

Tungsten coil filament is held/supported by two intermediate supports mounted on the pinch of the stem (made from molybdenum increases refraction) and attached to a nickel coated lead-in/out wire (increase conductivity) at either end of the filament. 

The lead-in/out wires and complete circuit is connected in sections.  Lead-in/out wires are fused to dumet wires.  Lead-in wire section is connected to the electrical foot contact.  Foot contact isolated from the base contact using insulation (vitirite – generating high resistance).

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Lead-out wire is fused to copper coated wire, which creates an electrical contact with the the base contact (side of the cap of the bulb) on the cap (completing a closed circuit allow flow of electrical energy),  The fuse wire area is attached to lead-out wire housed in the chamber (containing ballotini), to provide safety cut off. 

The copper wires is passed though the cap (base contact) and fused to a brass contact plate.  The wires form terminals and are insulated from each other. 

Applications

         Residential lighting

         Desk/table lighting

         Access and hallway lighting

         Cubical and closet lighting

(Incandescent light)

Principle

Current progresses through the electrical foot contact and channelled through the lead-in wire to the filament.  Filament absorbs the energy, heating the filament till visible light is released, till it is luminous.  Energy passes on through the lead-out wire.  Current is continuously passes through the circuit through the lead-in, filament, lead-out wire.  If current exceeds safety capacity of the circuit fuse, the fuse cuts the circuit.

2.3  Types of Lighting Systems (Luminescent)

2.3.1 Fluorescent (Tube)

Construction

A glass discharge tube with cathodes (electrode coils) are housed on a stem, fused (sealed using basing cement) to both the ends of the discharge tube (creating air tight seal).  Tiny (small diameter) glass tube protrudes through base of the stems.  Bi-caps are attached to ends of the glass stem making contact with the lead-in/out, creating complete electrical circuit.

Cathodes consists of electrode housed on a glass stem.  The Stems perimeter is fused to discharge tube.  A floating metallic electrode shield surrounds the electrode (prevents blackening and flickering).  The electrode comprises of coiled wire composed of tungsten (filament), due to the high operational temperatures generated.  An earth oxide material coats the wire (increases refraction and conduction efficiency).  

The filament is held by stainless steel support wires.  Lead-in/out are attached to either end of the support wires.  Lead-wires protrude out of the base at either end forming electrical pins (terminals).  Bi-cap pins reside over the electrical pins making contact forming an electrical connection (complete circuit).

Depending on the electrical properties desired, different variations (different gases, single or mixture) of inert gas mixture and tubing will be used.  Tiny quantity of mercury is injected with inert noble gas (argon, neon, krypton, xenon or mixture).

Phosphor layer is applied to the inside of the discharge tube and the metal bi-cap (converts UV light to visible light).  Outer layer of silicone wax is applied to discharge tubes (ensure starting and causes breakdown of moisture layers that may build up)

Application

         Residential lighting

         Public lighting

(Fluorescent Light)

Principle

High voltage is progresses through the circuit (above nominal operating voltage).  The high voltage acts as a starting voltage/heating current, which passes through the cathodes and chemical mixture located within the arc discharge tube.  This increases the temperature within the tube, the filament and increases the pressure within the arc discharge tube. 

The increase in temperature and pressure cause the arc tube content to vaporise/ionise and generate an arc discharge between electrodes, emitting light.  Electrons collide in the stream with the vaporised atoms, emitting light.  Electrons collision maintains cathode output temperature.  Heating current is no longer required.  The cathode current increase in output continuing the electron collision in the cathode.  This continuously vaporises the mercury present increasing its pressure.

Electron and mercury atoms collide.  Energy is transfer from the electron (moving at high accerlated speeds, above activation energy) to the mercury atoms. Atoms absorb the energy and are excited. UV radiation is emitted from these collisions which interacts with the phosphor coating on the glass absorbing the UV radiation and emitting visible light.

2.3.2 Metal Halide

Construction

An outer Bulb (clear or phosphor coated glass) is constructed from fused silica and attached to a metallic screw base.  A high pressure and temperature discharge arc tube resides on a frame located within the outer bulb.  An inert gas (halogen) reside within the arc tube.  A glass stem is attached to base of the cap, which holds the lighting structure.

A metallic support frame runs alongside/through the stem.  The frame is connect/attached to a glass dimple (strap connects the frame with the dimple) at the other end of the outer glass bulb (to retain stability).  The frame has an inbound and outbound section (protective sleeve and getter is present over the outbound section).  A lead-in/out wire (made of molybdenum) are attached to either end of the support.   Inbound section has the lead-in wire attached.  Outbound has the lead-out wire attached.  The support frame houses and holds a quartz arc tube (exhaust tip located in the side of the tube) in place.  Both these support the arc tube. 

Lead-in/out wire protrude through the stem.  Neck support can covers the lead-in/out wires at the bottom of the stem.  The lead-in wire section is connected to the electrical foot contact (from the Eyelet).  The foot contact is isolated from the base contact.   Lead-out wire is connected to base contact (side of the cap of the bulb). 

The circuit is composed of two different electrodes: starter and main.  The main tungsten electrodes (filament coated with thorium) are housed within the arc tube at either ends.  The electrodes are attached and protrudes out of the arc tube bases at either end and makes a connection with the support frame.  In so making a connection with the lead-in/out wires that are connect to the frame.  A Bimetal switch is localised between the starter and main electrode.  The starter electrode resides adjacent the main electrode.  A resistor is connected between the starter electrode protruding wire and the outbound support frame.

Tiny amount of mercury and metal iodine salt (increases CRI and lumen efficacy) are present with the arc tube.  The outer bulb can be coated in phosphor or be clear.  Inert gas within the arc tube prevents oxidation of the chemical mixtures within, when heated to high temperatures.  As well, the inert gas and the phosphor coating limits UV emissions.

Application

         Residential lighting

         Public lighting

         Arenas & Stadium lighting

(Metal Halide Light)

Principle

A high voltage is channelled, passing through the main electrode and starter electrode.  Starting voltage is channelled through starter electrode generating arc discharge between the two electrodes.  The start electrode has a high initial resistant.  Bimetal switch short circuits the electrodes lowering the resistance, allow an arc to be more easily generated. 

Discharge first ionizes the inert gas (halogen) and the mercury secondary.  Vaporised mercury enter the arc stream and increasing its strength, initiating an arc between the main electrodes at either end of the arc tube.  Electrons and mercury atoms collide in the stream.  Energy is transfer from the electron (moving at high accerlated speeds, above activation energy) to the mercury atoms.  Atoms absorb the energy and are excited emitting UV radiation.  Emitted radiation is absorbed by the phosphor coating bulb/tube and converted into visible light

The arc increases the temperature within the discharge tube causes the metal halides to increase in temperature and vaporised gradually, falling from the tube wall coating.  The metal halide compound enters the arc stream and breaks down into metals and iodine atoms and spreads.  Vaporisation of the metal halide increases strength of the arc.  Vaporation of the metal halide salts (metal iodide salt) into its components (iodine) determines output illumination efficiency and colour.

2.5 Lighting Systems Efficiency

Section 3 Application

3.1 Application of Lighting Systems

Rotating Machine

Metal Halide is a suitable lighting system for rotating machine.  Key features for rotating machine to consider: Illumination, glare & flickering/strobing

Rotating machine has high degree of hazards.  Metal halide lighting have high CRI 60-90 and lumen output and Lumen efficacy 75-100, this will reduce risk of injury when operating by increasing visibility. High illumination can cause daze.  Lighting output can be controlled by dimmers, ballast and design, contributing towards reducing injury.  Glare can cause machinery to perceived to be stationary, metal halide lighting can be manufactured to be glare free or intergrade with a dimmer/ballest to reduce voltage and glare.  End of life of lighting system can start strobing/flickering which can cause employee to feel ill or fizzy, in a daze.  Lighting system can be manufactured strobe/flicker free.  If non flicker free models are used they can be easily control by reducing voltage using ballests (reducing light output) or colour rendering filter (netural or light pink/red filter).

Vehicle Manufacturing plant Paint Sub-assembly

Fluorescent lighting is a suitable lighting system for assemble lines.  Key features for paint assemble line to consider: use of flammable substance (paint), require correct colour rendering & glare control.

Fluorescent light have a high CRI 74-90.  This allow better colour resolution for application of paint. Lighting cannot naturally be control, the intergradation of dimming ballast allows control of the lighting reducing glare.  It has a low flammability/explosion probability.  This reduces chances failure and of ignition external flammable paint supplies

Warehouse

Warehouses consist of several features that should be considered for selecting a suitable lighting fixture. 

         Large area of space.  

         Large quantity of shelving stacked on top of each other (reduced lighting space), aligned in rows.

         Continuous personal/forklift movement. 

         Office, and bay space.

Warehouses operate variation of three lighting options to choose from: metal halide, fluorescent and LED.  Analysing and comparing the three lighting options LED is the most suitable option to be considered for applying in a warehouse.  Key features for warehouse to consider: cost, maintenance & replacement, area, illumination & energy usage.

3.2  Advantages & Disadvantages

3.2.1 Advantages 

         Lifespan

LEDs have long lifespan, 35000-50000 hours lifespan (with extremely efficiency LEDs lasting 50000 – 100000 hours).  Warehouses area is large, with large quantity of lighting fixtures required.  The long lifespan reduces time and expense of replacement and maintenance.

         Efficiency

LEDs have a high lumen efficiency 80-90% (output 135 lumen/watt), between 10-20% converted to heat, as well as having a high lumen efficacy.  High efficiency and efficacy will require less energy and cost to illuminate the large area.  LEDS have a higher lumen output, they uses less energy for great output.  This reduces energy consumption generated by the larger area required lighting, reducing cost.  More energy is being converted into light than heat.  Low heat output is both advantage and disadvantage for the warehouse.  Low heat output reduces wasted energy output and reduces require cooling equipment required (increasing cost), but in cold climates and seasons it reduces heat that would contribute to the heating of the warehouse causing central heating to be increased in the warehouse, increasing energy and cost.

         Warm-Up Period

LEDs have no warm-up period.  Waste energy is not present, when entering.  This allows instant illumination and instant work to be conducted, reducing wasted excess energy and time (working hours).

3.2.2 Disadvantages

         Purchase & Installation Cost

LEDs Initial cost of purchase and installation are more expensive than other less efficient lighting structures appropriate for warehouses (metal-halide & fluorescent).  Warehouses have large areas and depending on the size of the company, cost for purchase and installing the LEDs maybe too high.  Less efficient lighting structure may have to be purchased causing decreased efficiency and greater costings for the warehouse.  Incorrect installation reduces illumination, increasing energy lost, reduced vision, increasing maintenance, labour, costing and time.

         Glare

LEDs high lumen efficacy brightness.  High illumination with LEDs increases glare projected.  Glare is created by poor optical settings of the electric light unit and high intensity of the LEDs illumination.  Glare can cause hazards and other health effects and reduce performance/efficiency for the workers.  A traded-off is applied, decreasing LEDs efficiency and operational performance.  Either by installing low grade LEDs, installing dimmers & sensors.  A lower degree of LEDs system can be chosen, installation of glare control or reducing light output (decreased efficiency) to decreases the glare.

         Directional

LEDs have a limit field of light projection.  A spherical range of 180o.  It has a low limit range of light projection, below 100 meters (10s meters), limiting them to low range use.  Application of LEDs in large areas is difficult, due to its limit field and range.  Multiple LEDs would need to be employed to cover 360o and reducing original desired height of installation (though installation on light fitting).  A single point of coverage or directional set up of lighting is required to employee better coverage.

Section 4 Conclusion

4.1  Conclusion

In conclusion the three lighting system chosen for analyses was incandescent, fluorescent and metal-halide. 

The warehouse was chosen for the application environment for examining for a suitable lighting system.  Three option where available to choose between fluorescent, metal halide and LED.  LED was the most suitable option for chosen application environment.

References

References

         Electrical4U. (2019). Incandescent Lamp Principle and Construction of Incandescent Lamp | Electrical4U. [online] Available at: https://www.electrical4u.com/incandescent-lamp/ [Accessed 29 Apr. 2019].

         Lamptech.co.uk. (2019). The Fluorescent Lamp. [online] Available at: http://www.lamptech.co.uk/Documents/FL%20Introduction.htm [Accessed 29 Apr. 2019].

         Staff, S. (2019). Lighting Comparison: LED vs Metal Halide Lights. [online] Stouchlighting.com. Available at: https://www.stouchlighting.com/blog/led-lights-versus-metal-halide [Accessed 29 Apr. 2019].

         Staff, S. (2019). Lighting Comparison: LED vs Incandescent Lighting. [online] Stouchlighting.com. Available at: https://www.stouchlighting.com/blog/light-comparison-led-lighting-vs-incandescent-lighting [Accessed 29 Apr. 2019].

         Staff, S. (2019). Lighting Comparison: LED vs Fluorescent and CFL. [online] Stouchlighting.com. Available at: https://www.stouchlighting.com/blog/fluorescent-vs-led-vs-cfl [Accessed 29 Apr. 2019].

         Electrical4U. (2019). Metal Halide Lamps | Electrical4U. [online] Available at: https://www.electrical4u.com/metal-halide-lamps/ [Accessed 29 Apr. 2019].

         Blog, B., Lights, A. and Myers, M. (2019). Advantage & Disadvantage Of LED Lights. [online] Berkeys Air Conditioning, Plumbing & Electrical. Available at: https://www.berkeys.com/2016/11/16/advantage-disadvantage-led-lights/ [Accessed 29 Apr. 2019].

         Tlc-direct.co.uk. (2019). [online] Available at: https://www.tlc-direct.co.uk/Technical/Lighting/L1_Regs/Lumen_Complies.htm [Accessed 6 May 2019].

         Emsd.gov.hk. (2019). Energyland – Energy-efficient Fluorescent Tubes. [online] Available at: https://www.emsd.gov.hk/energyland/en/appAndEquip/equipment/lighting/tubes.html [Accessed 6 May 2019].

Appendix

Appendix

Appendix A  Types of light systems.

Types of Lighting Systems

Appendix A

Lighting Systems

Incandescent

Luminescent

Luminescent

SSL (LED)

ESL

Halogen

Incandescent

HID

Fluorescent

Metal-Halide

CFL

Mercury-Vapour

High-Pressure Sodium

Tube

Low-Pressure Sodium