Friday, December 19, 2014
Wednesday, December 17, 2014
Various Losses In Transformer
Losses in Transformer
As the electrical transformer is a static device, mechanical loss in transformer normally does not come into picture. We generally consider only electrical losses in Transformer . Loss in any machine is broadly defined as difference between input power and output power.When input power is supplied to the primary of transformer, some portion of that power is used to compensate core losses in transformer i.e. Hysteresis losses and Eddy current losses in transformer core and some portion of the input power is lost as I2R loss and dissipated as heat in the primary and secondary windings, because these windings have some internal resistance in them. The first one is called core loss or iron loss in transformer and the later is known as ohmic loss or copper loss in transformer. Another loss occurs in transformer, known as Stray Loss, due to Stray fluxes link with the mechanical structure and winding conductors.
Copper Loss in Transformer
Copper loss is I2R loss, in primary side it is I12R1 and in secondary side it is I22R2 loss, where I1 & I2 are primary & secondary current of transformer and R1 & R2 are resistance of primary & secondary winding. As the both primary & secondary currents depend upon load of transformer, copper loss in transformer vary with load.Core Losses in Transformer
Hysteresis loss and eddy current loss, both depend upon magnetic properties of the materials used to construct the core of transformer and its design. So these losses in transformer are fixed and do not depend upon the load current. So core losses in transformer which is alternatively known as iron loss in transformer can be considered as constant for all range of load.
Different Types Of Transformers
Types Of Transformers
Transformers can be categorized in different ways, depending upon their purpose, use, construction etc. The types of transformer are as follows,- Step Up Transformer & Step Down Transformer – Generally used for stepping up and down the voltage level of power in transmission and distribution power network.
- Three Phase Transformer & Single Phase Transformer – Former is generally used in three phase power system as it is cost effective than later but when size matters, it is preferable to use bank of three single phase transformer as it is easier to transport three single phase unit separately than one single three phase unit.
- Electrical Power Transformer, Distribution Transformer & Instrument Transformer - Transformer is generally used in transmission network which is normally known as power transformer, distribution transformer is used in distribution network and this is lower rating transformer and current transformer & potential transformer, we use for relay and protection purpose in electrical power system and in different instruments in industries are called instrument transformer.
- Two Winding Transformer & Auto Transformer – Former is generally used where ratio between high voltage and low voltage is greater than 2. It is cost effective to use later where the ratio between high voltage and low voltage is less than 2.
- Outdoor Transformer & Indoor Transformer – Transformers that are designed for installing at outdoor are outdoor transformers and transformers designed for installing at indoor are indoor transformers.
Tuesday, December 16, 2014
Why Motor is rated in kW/HP instead of kVA?
We know that Transformer, Generator, Alternator are rated in KVA. Designer of these equipments doesn’t know on which power factor this equipments will work. The working power factor of Transformer, Generator or Alternator depends on the nature of connected load such as resistive load, capacitive load, and inductive load. But Motors will work on fixed Power factor, i.e. motor manfacturer will decide on which power factor it should work for getting maximum efficiency and thats the reason why motor is rated in KW on Motor nameplate. That’s why Motors are rated in kW or HP (kilowatts/ Horsepower) instead of kVA.
Monday, December 15, 2014
Home Appliances And Their Power Consumption
 |
| Click Here To Connect Us On Facebook |
Sunday, December 14, 2014
Saturday, December 13, 2014
Why we can’t store AC in Batteries instead of DC?
We cannot store AC in batteries because AC changes their polarity upto 50 (When frequency = 50 Hz) or 60 (When frequency = 60 Hz) times in a second. Therefore the battery terminals keep changing from Positive (+ve) to Negative (-Ve) and vice versa, but the battery cannot change their terminals with the same speed, so that’s the reason why we can’t store AC in Batteries.
Also when we connect a battery with AC Supply, then It will charge during positive half cycle and discharge during negative half cycle because the Positive (+ve) half cycle cancel the negative (-Ve) half cycle, so the average voltage or current in a complete cycle is Zero. So there is no chance to store AC in the Batteries.
Subscribe to:
Posts (Atom)