Tuesday 26 September 2017

How to Work automatic transfer switch(ATS) with dual power supply

1) what is the ATS ?
ATS is abbreviation of automatic transfer switch, it is use to change over power source of dual feedings i.e Primary source & secondary source.

2) incoming source of ATS.
ATS connected from two source
👍primary_source generally electricity supply from government/private organisation and  secondary_source will be generator and interrupted power supply(UPS) etc.

3) Function of ATS.

An automatic transfer switch (ATS) is a device that automatically transfers a power supply from its primary source to a backup source when it senses a failure or outage in the primary source. When a failure occurs in a primary power system, the ATS invokes a standby power source, such as an uninterruptable power supply. An ATS can also start up more long-term backup power systems, such as local diesel generators, to run electric equipment until utility power is restored.

Since the ATS is connected to both primary and backup power sources, it serves as an intermediary between equipment and the power supplies, acting as an electrical relay. An ATS can also act as a redundant, rack-mounted power supply for equipment that is connected to a power source with only one cord.

In the data center, it is vitally important to have uninterrupted power. To achieve this goal, the systems in the power path must be properly maintained and tested. To ensure reliability in the event of a power outage, data center administrators need to routinely monitor the ATS.
 ATS units can channel considerable amounts of energy, which can put heavy stress on the electrical contacts involved, so regular maintenance is critical.

4)How to remotely control an automatic transfer switch.

As you see on the automatic transfer switch Video, you can connect a switch for a remote control from BMS (building management system).
In side ACB under voltage coil also function to open Load supply if incoming voltage down to under 200 volt for domestic use and 370 volt for 3 phase power system.

Sunday 24 September 2017

Important of Power factor(pf) in AC system.

A number of power quality issues including electrical harmonics, poor power factor, voltage instability and imbalance, impact on the efficiency of electrical equipment's.

1)What is power factor ?

In Alternative current (AC) system have two quantity namely voltage and current, the power factor has cosine angle between the voltage and current.
Pf will be lagging & leading depends upon load connected.
if inductive load such as motor pf of the circuit lagging,where capacitive load such as capacitor
have leading pf.

2)Lossless because low power factor(pf) ?

~High energy uses and costs.
~ Failure of motors.
~Failure of electrical and  electronics equipment.
~Malfunction of Fuses & Circuit Breakers.
~Unstable equipment operations.
~Overheating of transformers and switch-gears.

3)How does Power Factor Correction work?

#see_video_how power factor improved

Power Factor is the ratio of Active Power(KW) to the Apparent Power(KVA) drawn by any load. 

Low power factor leads to increased transmission and distribution losses leads to increased electricity bills without increase in productivity, heating & hunting of DG with increased fuel consumption.

Pf =kw/KVA
True power/apparent power.
Generally power factor in varies between 0 to 1.
it is best practice to maintain power factor unity(1).

 PFC systems increase the efficiency of power supply, delivering immediate cost savings on electricity.

    Real Power is the power that actually powers the equipment and performs useful, Productive work.

    Reactive Power is required by some equipment (e.g. transformers, motors and relays) to produce a magnetic field for operation; however it does not perform any real work.

    Apparent Power is the vector sum of Real and Reactive Power and corresponds to the total power required to produce the equivalent amount of real power for the load.

A capacitor generate leading power factor for compensation of inductive power factor,
In term of KVAR.
Where KVAR known reactive power,equal to

Voltage x current x sin Phi.

4) how to calculate pf.?

Q-1) a 10 KW induction motor operate in 220 volt 50 hz power supply, if motor 50 ampere current ,then calculate power factor of motor.
Q-2) if require maintain power factor 0.98,calculate VAR value of capacitor.

Given in Q-1
Active power(KW)=10
apparent power =V x I x cosine

Cosine = KW/VI

if require 0.98 pf.
KVAR =V x I x sin phi
           = V x I x √[ 1-pf x pf]

              11 x √[1-0.98 x0.98]
            =11 x 0.4
             =0.440 KVAR

Hence 440 VAR capacitor bank require to maintain 0.98 pf of induction motor, to efficient operation and save electricity bill.

Saturday 23 September 2017

Air property of air-conditioning systems

hello friends,
  1. Today discuss regarding air properties used in air conditioning system.

The purpose of Air-conditioning?

1)Comfort Air-conditioning for human beings; 
2)Industrial Air-conditioning for equipment, raw material 
and goods


 It is the temp. which the thermometer can measure in air.
 For HUMAN comfort/relaxing Temperarure will be 21 deg.  

WET BULB TEMP.(w.b.t): 

      If a moist wick is placed over a thermometer bulb, the evaporation of moisture from the wick will lower the thermometer reading .This temp. is known as the w.b.t.
     wet bulb temperature measurement done by cyclometer with two thermometer installed,one for Dry bulb 7 second for Wet bulb temperature

DEW POINT (d. p): 

is the temperature below which water vapor in the air start to condense known DEW point.


Is the presence of moisture or water vapor in the air. the amount of humidity in the air affects the rate of evaporation of perspiration from the body. Dry air causes rapid evaporation.


     Is a term used to express the amount of moisture in a given sample of air.also the amount of water vapor present in air expressed as a percentage of the amount needed for saturation at the same temperature. for human filling comfort with Relative Humidity between 55 % to 65 %.