Difference between MCB & Isolator

MCB:

MCB is Miniature circuit breaker,which used to  protect the electrical equipment from over load and short circuit conditions.

There are 5 type of MCB in the market based on the magnetic trip current,

1.Type B

2.Type C 

3.Type D 

4.Type K 

5.Type Z 

Based on the applications and demand, we are using the MCB's in domestic & industrial area.

There are two trip unit available in MCB, there are thermal trip unit and magnetic trip unit.

When over current is drawn by the electrical equipment, thermal trip unit trip the MCB,whereas magnetic trip unit will trip the MCB when the short circuit occurs .

Isolator :

Isolator used to isolate the electrical equipment from power supply or electric current for servicing and maintaining the equipments.

There is no protection system available

If over load occurs, the isolator will burns out.

Difference between MCB and Isolator:

        MCB                                   Isolator 

1. Automatice device        1.Manually operated 2.Protection available      2.Not available 

3.High Cost                           3.Low cost

4.Electronic circuit            4.Mechancial device 

made by transistors             act as switch

5.Arc suppression              5. Not available 

mechanism available 

6.High current                    6. Low current 

withstand                                  withstand 

capacity                                     capacity 

7.ON load device                  7.OFF load device

Please comment if you may have any doubts. 

How to calculate GPM of AHU/CSU/FCU/VAHU/PAHU

GPM stands for gallon per minute.

It is one of the unit  used to measure the water volumetric flow rate. 

The stand formula for calculating the TR as follow,

TR = (GPM × Delta T)/24 

For this,we can find out the GPM 

GPM =( TR×24)/Delta T 

Where GPM is flow rate 

              TR is ton of Refrigeration 

              Delta T is temperature difference between supply and return chilled water

Let us consider AHU and its  inlet and outlet water temperature is 30 degrees fahrenheit and 38 degrees fahrenheit and TR is 10.

Apply all these values in the GPM formula

GPM = (10×24)/(38-30)

          = 240/8

  GPM=30 

Here the GPM depends only on temperatures, as the TR is constant throughout the process.

How to calculate CFM of the room

CFM stands for  cubic feet per minutes.

To calculate CFM, we need to determine the volume of the room and ACH (Air changes per hour) firstly. 

We all know how to calcualte the volume. 

The product of length , width and height called as volume of the room.

Let us consider the room having 10 feet length and 10 feet width and 10 feet height.

So volume of the room comes around 1000 cubic feet or F3.

Next we need to know about ACH.

ACH calculated as how many times air entering and leaving  from the HVAC system in a one hour called as ACH.

ACH depends on temperature and structure of the building and capacity of the equipment etc.

Let us assume ACH as 6 for the proposed room

Now we can calcualte the CFM and refer below,

CFM =(ACH ×Volume of the room)/60

          =(6 ×1000)/60

          = (6000/60)

          CFM=100 cubic feet /min or F3/min

Hope you understand the calculation and other consideration. 

Regarding ACH ,we will post the details and standard table following across the industry. 

How bad distilled water affect our inverter lead acid battery perfomance

Hello Friends,

As you know, the power generation in India is  low than our demand. To meet out this, our government is trying to  implement more power stations like thermal, nuclear, solar, wind plants etc..

During the power cut, most of us are using the home inverter, in order to carry on our routine work.

Hence choosing inverter and its battery is very most important and also maintenance of those are also much important.

Generally, we all are using lead acid batteries in our home and we need to topping up the distilled water when the acid level is goes down.

Here we need to take more care for buying the distilled water.

The water should have 5 ppm(parts per millions) or below and it may be the recommendation by many of manufacture.

But in recent report, the researcher advised us to not to buy distilled water from road side shops.

Because the water having the ppm of 30 and more.

To buy the good distilled water, I am recommending you to procure one TDS meter which cost around just Rs.200 only.

If we use TDS meter, we can check the TDS level of distilled water and if the value is less than 5ppm, we will add otherwise we can ignore. 

Incase if adding the bad distilled water, it will affect the battery performance and its life.

First, the battery will loose its charge holding capacity and if we adding the same bad water for a certain period, you will get low battery power backup problems and finally your battery will die one day.

So please be caution on buying the distilled water and get the TDS meter to ensure the TDS level before topping up.

Thanks.

What is Bus Coupler

Bus coupler is a device used to couple the bus one with another without any power interruption and without creating dangerous arc.

Bus coupler may used in HT panel and MV panel and LT panel etc.

The bus coupler may be a ACB or VCB or MCCB or else MCB.The selection of breaker will completely based on the customer usage. 

Let us imagine, we have one 1000KVA transformer and one 500KVA transformer. 

The first one is providing the power supply to the Healthcare industry and the second one is providing the power supply to the data center.

And consider there are no redundancy of those the transformer. 

In this case, if any one transformer failed ,the load depends on that transformer does not have  any backup power supply which impact the operation of healthcare industry and data center.

But if we use the buscoupler between both our transformers ,we can shift the power supply one over to another and vice versa and there would not be a chance to the interruption of power supply at any situation. 

What is Bus Bar and how to calculate bus current carrying capacity

Busbar is defined as conductor or group of conductor used for transferring the power supply from incoming feeder and distribute them into outgoing feeders.

In other word,  it is type of electrical junction in which all the incoming and outgoing current meet.

Busbar are available in aluminium, copper, steel, iron, gold, silver etc..

But we are mostly using the aluminum and copper made busbars.

Bus bar are coming in market at different sizes

Like 20x4mm,20x6mm,20×10mm,25x5mm,25x6mm,25x10mm,30x10mm,40x10mm,80×8mm,100x10mm etc..

Let us discuss on current carrying capacity of bus bars..

Aluminium:

There is a thumb rule to calculate current carrying capacity. 

CCC = area of bus bar x 0.8 

Example:

We consider the bus bar size as 100x10mm,where 100mm is width of busbar and 10mm is thickness of busbar.

To calculate area,we need to multiply both w and t .

Area =100×10=1000Sqmm...

Now apply this area into above our thumb rule,

CCC= 1000×0.8=800A ..

So the current carrying capacity of aluminum busbar will be 800A ..

Copper:

Here the thumb rule is area of busbar x 1.4A.

We use the same busbar size I.e 100x10mm

We have already calculated the area .

So CCC =1000×1.4=1400A

So the current carrying capacity of copper busbar willbe 1400A ..

Type of inverter batteries and its pros and cons

Type of inverter batteries and its pros and cons

Lead acid batteries :

It is a most commonly used inverter batteries. It requires regular maintenance. We need to topping up the electrolyte level based on the demand.
It emit the dangerous gas during the charging and discharge time.

Advantage:

1.Less weight
2.Low cost

Disadvantage:

1.life span is very short I.e 3 to 4 years
2. Ventilation is required, as it emits the gas.

SMF batteries:

It is the updated version of lead acid batteries . It does not require any special maintenance and no need to topping up the electrolyte.

Advantages:

1.Less maintenance
2. Less weight

Disadvantages:

1.cost is slightly more compare with lead acid batteries
2. Life span is short I.e 3 to 4 years based on brand selection

Tubular Batteries :

It is good efficiency inverter battery compared with other type of batteries.
It life span comes around 8 to 10 years .After 10 years, you can use the cells by doing some maintenance carried out by the manufacturer.

Advantages :

1. No maintenance required
2. Life span is good

Disadvantages: 

1.cost is too much 

Types of inverter Batteries

There are three types of inverter batteries we are generally using and available in the market.

 1. Lead acid batteries 

2. Sealed maintenance free batteries

3. Tubular batteries 

Selecting proper bateries is very important. Because it is backup of our emergency load. 

So we need to take more caution and more take while selecting /procuring this inverter batteries 

Most of us buying the inverter in known brand and batteries in unknown brands. This is not a good combination and good decision too.

By end of reading this article, you can choose your inverter batteries based on your load requirement. 

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