soft starter

Difference between DOL, Star Delta, VFD and Soft starter

Electrical Technology

Electrical TechnologyDOL-Direct on line Starter: here the starting current will be 6 times of full load current. A bimetallic thermal overload relay provides protection against the over load. There will be no reduction of starting torque during starting. Star Delta Starter: In order to limit the starting current of motors this method is followed. Initially…

How to calculate cable size for LT Motors

Electrical Technology

Electrical TechnologyWhat is the difference between LT and HT Motors? Well, as the word LT (Low Tension i.e. Low Voltage) and HT (High Tension i.e. High Voltage) or low torque and high torque respectively describe the whole story itself. its also depends on the availability of supply voltage, i.e. in USA and EU, LT Motors…

battery

Battery charging calculation

Electrical Technology

Electrical TechnologyHow to Calculate the charging Time and Charging current for battery Charging? Easy Battery Charging Time and battery Charging Current Formula for Batteries. ( with Example of 100Ah Battery). Battery Charging Current and Battery Charging Time formula Here is the formula of Charging Time of a Lead acid battery. Charging Time of battery =…

numerical relay

Why Numerical Relay over Electromechanical Relay

Electrical Technology

Electrical TechnologyAdvantages of Numerical relays 1.      Compact Size Electromechanical Relay makes use of mechanical comparison devices, which cause the main reason for the bulky size of relays. It uses a flag system for the indication purpose whether the relay has been activated or not. While numerical relay is in compact size and use indication on…

relay

Circuit Breaker Tripping Schemes

Electrical Technology

Electrical TechnologyCircuit Breaker Tripping Schemes Basically two types of tripping schemes which are given below:- Relay with make type contact. Relay with break type contact.   1) Relay with make type contact: In this scheme, the relays are connected in the stare, and contacts of each relay are connected in parallel and this parallel unit…

types of insulator

Causes of failure of insulator

Electrical Technology

Electrical TechnologyThe causes of the failure of insulator are :-   Cracking of insulator: The main cause of cracking is due the stress produced in the porcelain due to unequal expansion and construction produced in cement, steel and porcelain caused by seasonal heat cold, dryness, and dampness or by heating of the insulator. To avoid…

armature winding

Magnetic Saturation

Electrical Technology

Electrical TechnologyIf we increase the mmf of a magnet, the flux density inside the core to of the is also increased. Now we can ask a question, whether there is any limitation of increasing flux density in the core of magnet with increasing applied mmf. The answer is yes. There is a limit beyond which…

generator troubleshooting

Troubleshooting guide for generator

Electrical Technology

Electrical TechnologyBrief introduction The following problems listed below are provided the following: Known problems Possible causes of the known problems Repair to correct the known problems Fault diagnosis   1). When the starting switch is in the (ON) position, the engine crankshaft does not rotate. Possible causes: 1. Low battery output voltage Check the battery…

maintenance of transformer

Maintenance of Transformer

Electrical Technology

Electrical TechnologyA power transformer is most costly and essential equipment of an electrical transformer. So for getting high performance and long functional life of the transformer, it is desired to perform various maintenance activities. Not only that, a power transformer also requires various maintenance actions including measurement and testing of different parameters of the transformer….

vector group test of transformer

Vector Group Test of Power Transformer

Electrical Technology

Electrical TechnologyVector Group Test of Transformer The vector group of transformer is an essential property for successful parallel operation of transformers. Hence every electrical power transformer must undergo through vector group test of transformer at factory site for ensuring the customer specified vector group of transformer. The phase sequence or the order in which the…

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