Simple Calculation of Flood Light, Facade Light, Street Light & Signage Light-(Part2)


(B) Facade Lighting:

  • Normally Facade Lighting are used to illuminate Building area from Outer Side. 
  • There are three factor should be consider while designing of outdoor Facade Lighting.
  1. Setback
  2. Spacing
  3. Aiming

1) Setback:

  • The recommended setback should be 3/4 times the building height. 
  • If a building is 10 Meter tall, the recommended setback is 7.5 Meter from the building. 
  • If the locating the floodlight closer to the building will sacrifice uniformity and If setting it further back will result in loss of efficiency.
  • Setback distance = 3/4 x Building height
  • Setback distance =3/4 x (10 Meter) = 7.5 Meter 

a

2) Spacing:

  • Spacing of floodlights should not be exceeding two times the setback distance. 
  • If the setback is 7.5 Meter the floodlights should not be placed more than 15 Meter apart.
  • Spacing = 2 x setback distance
  • Spacing=2 x 5  = 15 Meter

b

3) Aiming:

  • The floodlight should be aimed at least 2/3 the height of the building.
  • If a building is 10 Meter high, the recommended aiming point is approximately 6.6 Meter high. 
  • After installation aiming can be adjusted to produce the best fine appearance. 
  • Aiming Point = 2/3 x Building Height.
  • Aiming Point =2/3 (10 Meter) = 6.6 Meter high

c

(C) Sinage Lighting:

  • Normally Sinage Lighting are used to illuminate Sinage Board either Floor Mounted or Pole Mounted
  • There are three factor should be consider while designing of Sinage Board Lighting.
  1. Setback
  2. Spacing
  3. Aiming

1) Setback:

  • When using floodlights to light a sinage, the setback should be 3/4 the sign height
  • If the sinage height is 18 Meter then the setback distance would be 13.5 Meter. 
  • If the floodlight closer to sinage will sacrifice uniformity while setting it further back will in a loss of efficiency.
  • Setback distance = 3/4 x sinage height
  • Setback distance =3/4 (18 Meter) = 13.5 Meter.

d

2) Spacing:

  • The spacing floodlights should not be exceed two times the setback distance. 
  • If the setback is 13.5 Meter, the floodlights should not be placed more than 27 Meter apart. 
  • Spacing = 2 x setback distance.
  • Spacing = 2 x 5 (Meter) = 27 Meter.

e

3) Aiming:

  • The floodlight should be aimed at least 2/3 up the sign.
  • If a sign is 18 Meter tall, then the floodlight should be aimed approximately 12 Meter high. 
  • Aiming can be adjusted to produce the best appearance. 
  • Mounting a full or upper visor to the floodlight can reduce unwanted glare. 
  • Aiming point = 2/3 x sign height
  • Aiming point =2/3 (18 Meter) = 12 Meter high

f

Street Light Pole Height & Spacing (as per CPWD):

  • There are four type of Street Light Pole arrangement.
  • One side Type.
  • Staggered Type.
  • Opposite Type.
  • Central Type.
  • As per CPWD we can calculate Pole Height and Spacing as per under

(1) One side Street Light Pole arrangement.

  • Pole Height = Width of Road.
  • Pole Spacing = 3 to 4 Times Height of Pole.
  • If the Road width is 8 Meter than
  • Pole Height=8 Meter
  • Pole Spacing =24 to 32 Meter.

g

(2) Staggered Type Street Light Pole arrangement.

  • Pole Height = 0.8 time Width of Road.
  • Pole Spacing = 3 to 4 Times Height of Pole.
  • If the Road width is 8 Meter than
  • Pole Height=6.4 Meter
  • Pole Spacing =24 to 32 Meter.

h

(3) Opposite side Street Light Pole arrangement.

  • Pole Height = 0.5 time Width of Road.
  • Pole Spacing = 3 to 4 Times Height of Pole.
  • If the Road width is 8 Meter than
  • Pole Height=6.4 Meter
  • Pole Spacing =24 to 32 Meter.

(4) Central Street Light Pole arrangement.

  • Pole Height = 0.8 time Width of Road.
  • Pole Spacing = 3 to 4 Times Height of Pole.
  • If the Road width is 8 Meter than
  • Pole Height=4 Meter
  • Pole Spacing =24 to 32 Meter.
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Simple Calculation of Flood Light, Facade Light, Street Light & Signage Light-(Part1)


Introduction:

  • Outdoor Lighting can be classified according to the location where it can be installed or its function which use for highlight landscape area.
  • Outdoor Lighting can be classified as
  1. Flood Lighting,
  2. Facade Lighting and
  3. Signage Lighting
  4. Street Light

(A) General Outdoor Flood Lighting:

  • Normally Pole mounted floodlights are used to illuminate general lighting area of parking lots and storage yards. 
  • There are three factor should be consider while designing of outdoor flood lighting.
  1. Mounting Height.
  2. Spacing
  3. Aiming Distance.
  4. Horizontal Aiming.

1) Mounting Height:

  • Mounting height should be one half the distance across the area to be lighted.
  • If the area to be lighted is 16 Meter, the lowest recommended mounting height is 8 Meter. 
  • Mounting height = 1/2 distance to be lighted
  • 1/2 (16 Meter.) = 8 Meter. 

1

2) Spacing:

  • When more than one Luminar / pole is required than distance between two adjacent luminar / Pole is 4 times Mounting height of luminar /pole.
  • If the mounting height of luminar /Pole is 8 Meter than distance between adjacent Luminar is 32 Meter.
  • Pole Spacing = 4 x mounting height.
  • 4 (8 Meter pole) = 32 Meter between poles

2

3) Vertical Aiming:

  • The fixture should be aimed 2/3 of the distance across the area to be lighted and at least 30 degrees below horizontal. 
  • If the area to be lighted is 16 Meter across, the recommended aiming point is 10.6 Meter.
  • Aiming point = 2/3 Distance to be lighted.
  • 2/3 (16 Meter) = 10.6 Meter aiming point
  • To minimize glare, the recommended aiming point distance should never exceed twice the mounting height.
  • If a pole is 8 Meter high, the vertical aiming point should not exceed 16 Meter.  
  • 2 (8 Meter mounting height) = 16 Meter. 

3

4) Horizontal Aiming:

  • When two floodlights is mounted to a single pole then horizontal aiming also must be considered.
  • Each floodlight should be vertically aimed according to the two-thirds rule. 
  • The floodlights should be aimed up to 90 degrees apart. 

4

Calculate Size of Ventilation Fan


  • Calculate Size of Ventilation Fan for Bathroom of 10 Foot Long,15 Foot width and 10 foot height .

Calculation:

  • Area of the Room=Length x Width x Height
  • Area of the Room=10 x 15 x 10 =1500 Cub. Foot
  • From the table Air Changing Rate (ACH) for Bathroom = 8 Times/Hour.
  • Size of Ventilation Fan = (Area of Room x ACH ) / 60
  • Size of Ventilation Fan = (1500 x 8 ) / 60 = 200 CFM
  • Size of Ventilation Fan = 200 CFM

 

Recommended Air Change Rates For  Room  (ACH)
Type of Room Air Change Rate /Hour Consider
Shower Area 15 To 20 20
Bathroom & Shower Rooms 15 To 20 15
Bathroom 6 To 10 8
Bedrooms 2 To 4 4
Halls & Landings 4 To 6 5
Kitchens 10 To 20 15
Living & Other Domestic Rooms 4 To 6 5
Toilets – Domestic 6 To 10 8
Utility Rooms 15 To 20 15
Cafés 10 To 15 15
Canteens 8 To 12 10
Cellars 3 To 10 6
Changing Rooms with Showers 15 To 20 15
Conference Rooms 8 To 12 8
Garages 6 To 10 8
Hairdressing Salons 10 To 15 13
Hospital Wards 6 To 8 7
Laundries & Launderettes 10 To 15 13
Meeting Rooms 6 To 12 7
Offices 4 To 6 6
Restaurants & Bars 10 To 15 12
School Rooms 5 To 7 6
Shops 8 To 10 9
Sports Facilities 4 To 6 6
Store Rooms 3 To 6 5
Workshops 6 To 10 8
Assembly rooms 4 To 8 8
Bakeries 20 To 30 25
Banks/Building Societies 4 To 8 5
Billiard Rooms * 6 To 8 5
Boiler Rooms 15 To 30 25
Canteens 8 To 12 10
Changing Rooms Main area 6 To 10 8
Changing Rooms Shower area 15 To 20 17
Churches 1 To 3 3
Cinemas and theatres * 10 To 15 12
Club rooms 0.12 0.12
Compressor rooms 10 To 15 15
Conference rooms 8 To 12 12
Dairies 8 To 10 10
Dance halls 0.12 0.12
Dental surgeries 12 To 15 15
Dye works 20 – 30 30
Electroplating shops 10 To 12  
Engine rooms 15 To 30 30
Entrance halls & corridors 3 To 5 5
Factories and workshops 8 To 10 10
Foundries 15 To 30 20
Glasshouses 25 To 60 50
Gymnasiums 0.6 0.6
Hospitals – Sterilizing 15 To 25 20
Kitchens – Domestic 15 To 20 15
Kitchens – Commercial 0.3 0.3
Laboratories 6 To 15 12
Lavatories 6 To 15 12
Lecture theatres 5 To 8 8
Libraries 3 To 5 4
Mushroom houses 6 To 10 8
Paint shops (not cellulose) 10 To 20 15
Photo & X-ray darkrooms 10 To 15 12
Public house bars 0.12 0.12
Recording control rooms 15 To 25 20
Recording studios 10 To 12 10
Shops and supermarkets 8 To 15 12
Squash courts 0.04 0.04
Swimming baths 10 To 15 12
Welding shops 15 To 30 20
 
 

What is Difference between UPS & Inverter


Introduction:

  • We are heavily dependent upon appliances that run on electricity such as fans, lights, AC, fridge, Computer and so on.
  • Whenever there is a power cut, electricity supply to these appliances is cut off and they stop working. However, if we have backup supply devices such as UPS and inverter, we can ensure Power supply to appliances and not bothered with power cuts.
  • However, people remain confused with the difference between a UPS and an inverter because UPS and inverters both are providing back up power supplies during main power outage.
  • Inverters are preferred more for general electric appliances whose working does not get affected by extended delays in power supply.
  • UPS are used for electronics appliances such as computer, servers, workstations, Medical Equipment which perform critical task and cannot tolerate delays in power supply.
  • An off-line ups (the standard) switch to the batteries in 3 to 8 milliseconds, after the main power has been lost. While Inverter changes over in about 500 milliseconds.

 UPS:

  • UPS means uninterrupted power supply.
  • Uninterruptible power supply (UPS) provides uninterrupted power to the equipment. It means switching time from power cut to battery power is vey less hence important and critical equipment like computer, desktop .Medical Instruments is not switch off and we can lose data.
  • A UPS is a complete system that is consisting of many parts that include batteries, a charge controller, circuitry any transfer switch for switching between the mains and back-up battery, and an inverter. An inverter is needed because the battery can only store DC power and we need to convert that back to AC in order to match the appliances connected in the main power line.
  • UPS= Battery charger + Inverter
  • UPS is nothing but inverter with inbuilt battery charger.
  • UPS give backup only 10 to 20 minutes. The main intention of it is to provide backup only for small time so that you can save the programs and data.
  • UPS also gives protection against line abnormalities like Surge, Voltage fluctuation, Under Voltage, Over Voltage, Spike, Noise.

Inverter:

  • Inverter circuit simple converters battery DC current to AC and supply
  • In inverter inverts the direct current to an alternating current. During normal condition electrical supply is direct feed to the Load. It also takes the supply from the AC source and charges the battery.
  • During the power cut, the inverter receives the supply from the battery and convert it DC to AC Power and provides the power supply to the electrical equipment.
  • Inverters purpose is to provide power backup to total home appliances, lights, fans.
  • Inverter uses flat plate or tubular battery to store electricity. So it requires continuous maintenance, needs to fill the distilled water toppings at regular intervals of time.
  • Inverter does not give protection against line abnormalities

Difference between UPS and Inverter:

 

Comparison of  UPS and Inverter
Descriptions UPS Inverter
Definition UPS means Uninterruptable Power Supply. Inverter is a device which converts DC electricity to AC
Function It is an electric circuit (device) which instantly backs up power supply for a gadget. The gadgets works continues to work on smoothly and there is no damage to it.

 

Inverter consist circuitry which converts AC to DC and stores in the battery. When power supply goes off, that DC power is converted back to AC and is transmitted to the respective electronic gadget.
Principles It first converts AC to DC Power to charge the battery than Convert DC Power to AC Power (Inverter) and this AC power is supplied to Load. However, UPS monitors the input voltage level and processes it in terms of voltage regulations.

UPS= Battery charger + Inverter

Inverter converts DC power (stored in its battery) to AC Power supplied to the devices. Normally AC Power charges the battery .It uses relays and sensors to detect when to use DC power or AC Power, for DC power.
Back up Time Power Back up for Short Duration Power Back up for Long Duration
Types (a) Offline UPS, (b) Online UPS and (c) Line-interactive UPS.

 

(a) Square Wave, (b) Quasi Wave,

(c) Sine Wave

Main Part Rectifier/charger, Inverter ,controller Inverter and controller.
Switch over Time 3 to 8 milliseconds. 500 milliseconds.
Voltage Fluctuations While voltage fluctuations in input supply can be adjusted by the UPS, the output voltages are desired to be as smooth as possible.

In smoothing the voltage outputs, UPS are considered better as compared to inverter.

 

Inverter does not give protection against voltage fluctuations
Circuitry Sophistication UPS circuitry is far more sophisticated than that of inverter’s Inverter has Simple circuit then UPS
Pricing UPS more expensive than an inverter. Inverter is less expensive than UPS
Application UPS are used for electronics Application such as computer, servers, Network Switches, workstations, Medical Equipment, Processing Equipment which perform critical task and cannot tolerate delays in power supply. Inverters are preferred more for general electric Application which working does not affected by extended delays in power supply.
Protection UPS provide protection against voltage spikes, voltage drops, instability of the main frequency and harmonic distortions Inverter does not provide protection against Line abnormalities.
Battery Used sealed maintenance free (SMF) battery Used flat plate or tubular battery
Battery Maintenance Do not require any maintenance. Requires continuous maintenance, needs to fill the distilled water toppings at regular intervals of time
Energy Consumption More due to constant battery Charging Less

Conclusion:

  • The UPS and inverter both provide the backup supply to the electrical system. Two major differences between the UPS and inverter are that
  • The switching of UPS from the main supply to the battery is very immediate so it is used to provide backup power of important or critical electronics equipment. whereas in inverter the switching from mains supply to battery takes times so it used to provide less important electrical equipment.
  • The UPS provide protection to the load against Spike, Voltage fluctuation, Noise while Inverter does not provide any protection to the load.

(3) For Short Circuit Protection (Magnetic Setting):


Example for Setting of MCCB  for Motor Circuit

  •  When we select an MCCB for motor application, it is necessary that the instantaneous release setting in the MCCB is set to a value higher than the highest anticipated Motor magnetizing inrush current during switching-on the motor.
  • The values for magnetizing inrush current (sub transient current) are higher in case of high efficiency motors as compared to standard efficiency motors.
  • By theoretical and empirical means it is established that the maximum ratio between peak and LRC can go up to 2.5 for high efficiency motors.

Motor Starting Current:

  • Motor starting current is one of the most important electrical parameter of motor to understand its electrical characteristics.
  • It is important to note the distinction between inrush current and starting current
  • The current drawn by the motor in different phases are.
  1. Inrush Current (Sub transient phase)
  2. Starting or Lock Rotor Current (Transient phase)
  3. Steady state operation.

Untitled

Inrush Current (Sub transient phase)

  • During the initial phase of motor starting Current drawn by motor is known as inrush current or peak current.
  • Inrush current is the current drawn between switch on and when the magnetic fields are established in the motor this current is due to magnetizing inrush component of the motor starting current.
  • Inrush Current: It is generally 13 to 17 x FLA for older motors to New Motor.
  • The duration of inrush current: It is in milliseconds.
  • Motor circuits are highly inductive. Motor can be started at any point on voltage wave of the circuit. Depending on the initiation of the circuit i.e. point on the voltage wave.
  • The magnitude of the
    asymmetry is directly related to X/R ratio of the circuit.

Starting Current (Transient phase)

  • Motor starting current or Lock Rotor Current is the current drawn while Motor is accelerating to full speed.
  • Starting Current: It is depend upon Starting method of Motor
  • For DOL Starter : 6 to 8 x FLA
  • Star- Delta: 2 to 3 x FLA
  • Auto Transformer: 2 to 3 x FLA
  • Soft Starter: 3 to 5 x FLA
  • VFD: 1.5 x FLA
  • The duration of Starting current: Depend upon Load and Application (10 To 40 Sec)

The magnetic settings for Motor should be as follows:

  •  Motor Starting Current < Magnetic Setting of MCCB < Short Circuit Current
  • The MCCB should not trip during starting of the motor. Therefore setting should be 1.3 times the starting current. Normally the starting current will be 6 times the full load current of the motor. Therefore it will be 7.8 times the full load current.
  • However you have to calculate the short circuit current at the motor terminal. This depends on source fault level at the bus feeding the motor and cable impedance between the MCCB and motor. The setting on the MCCB should be less than the calculated short circuit current.
  • Motor Acceleration Time < Magnetic Time Setting of MCCB
  • Another important consideration is the acceleration time should be less than the time set on the MCCB for the magnetic setting.

Calculate ventilation for Transformer & DG Room


55

  • Calculate Heat Loss of Electrical Equipment in Electrical / DG Room.
  • Calculate Air Quantity Required for Ventilation.
  • Calculate No’s of Ventilation Fan.
  • Calculate Rating of Ventilation Fan.

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Setting of overload, Short circuit & Ground Fault Protection of MCCB (PART-2)


(2) For Short Circuit Protection (Magnetic Setting):

  (C) Short Time pickup Current Setting (Im):

  • Short time protection is time-independent.
  • It is determines or sets the level of fault current at which the short-time trip delay countdown is actuated.
  • Short Time Pick up Value (Im) (multiplied by the ampere rating) sets the short circuit current level at which the circuit breaker will trip after the set time delay.
  • The short-time pickup (Isd) sets current level (below instantaneous trip level) at which circuit breaker will trip after the preset time delay.
  • Standard Practice for Setting:
  • No trip for a current below 80% of the short time setting
  • Trip for a current equal to 120% of the short time setting
  • The trip time is Less than 0.2 s for a short time protection with no time delay and equal to the value of the time delay tsd for a protection with time delay

(D) Short time delay Setting ™:

  • Short Time delay sets the amount of time the breaker will carry both a low level and high fault currents before tripping.
  • tm sets length of time the circuit breaker will carry a short circuit within the short-time pickup range.
  • Delays bands are labeled in seconds of short-circuit current at 10 times the ampere rating.
  • The short time delay can be set to I2t On and I2t OFF settings (Inverse Time Delay).
  • (A) I2t OFF: Gives Constant time delay usually in multiplication of 0.5 sec. It has not inverse-time delay Characteristic. It is used for coordination with other circuit breakers with electronic trip devices and for coordination with thermal-magnetic circuit breakers.
  • (B) I2t ON :Gives an inverse-time delay that resembles the time/current characteristics of fuse It is used for coordination with fuses and upstream transformer

(3) For Instantaneous Trip (Short Circuit Protection):

(E) Instantaneous Pickup Setting (Ii):

  • Instantaneous protection is time-independent.
  • It is determines the level of fault current that will actuate a trip with no time delay.
  • Ii value (multiplied by the ampere rating (In)) sets the short-circuit current level at which the circuit breaker will trip with no intentional time delay.
  • This protection trips to eliminate quickly high value currents and its trip times cannot be set
  • The instantaneous function will override the short-time function if the instantaneous Pickup is adjusted at the same or lower setting than the Short Time Pickup.
  • Standard Practice for Setting:
  • No trip for a current below 80% of the instantaneous setting
  • Trip for a current equal to 120% of the instantaneous setting
  • The trip time is less than 0.2 second.

 (4) For Ground Fault Protection:

(F) Ground Fault Pickup Setting (Ig):

  • It is determines the level of fault current at which the ground fault trip delay countdown is actuated.

(G) Ground Fault Delay Setting (Itg) :

  • It is determines the amount of time the breaker will carry a ground fault before tripping.
  • It can be set to I2t On and I2t OFF settings.
  • (A) I2t Response:I2t Out ,For coordination with other circuit breakers with electronic trip devices and for coordination with thermal-magnetic circuit breakers.
  • (B) I2t Response: I2t In ,For coordination with fuses and upstream transformer

 Example for Settings of MCCB for Protections

Example1: We have Sub feeder MCCB Size of 2000A, Short Circuit Current is 4000A. Maximum Load Current is 1000A .What is Over current (Long Time) and Short Circuit (Short Time) and Instantaneous setting of MCCB.

  • Here In=2000A

Over current Setting:

  • Dial Setting=(Load current / MCB Rating) =1000/2000=0.5 , set Dial at 0.5
  • Over current Setting Ir=0.5xIn =0.5X2000=1000A
  • For Set Over Current Time Delay: It is necessary to overview Over current Time delay of downstream MCCB and Upper stream MCCB for better coordination otherwise for downstream fault upper stream MCCB gives tripping.
  • Downstream Over current Time Delay< Over current Time Delay< Upper stream Over current Time Delay.
  • In Our example it is last MCCB in circuit and upper stream MCCB Over current delay setting is 2 Sec so Select tr=1 Sec.

Short Circuit Current Setting:

  • Dial Setting=( Short Circuit Current/ MCB Rating) =4000/2000=2
  • Short Circuit Setting Isd=2xIn=2×2000=4000A
  • Downstream Short current Time Delay< Short  current Time Delay < Upper stream Over current Time Delay Short  current Time Delay
  • Our example it is last MCCB in circuit and upper stream MCCB Short Circuit current delay setting is 0.4 Sec so Select Isd=0.2Sec.
  • For coordination of other MCCB we need I2t ON with 0.2 Sec delay.

Instantaneous Tripping Setting:

  • Instantaneous Tripping gives instant tripping without any delay for switching or short Circuit current.
  • Instantaneous Tripping >= Short Circuit Tripping Setting
  • If We can set Ii=3xIn =3×2000=6000A , It will full fill our requirement
  • Here Ii>Isd=6000A>4000A.

 

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