Tuesday, 3 December 2013

DOL STARTER



A DOL( direct on line) starter is a type of motor starter which is basically simple and attaches the motor terminals directly to the power supply. It normally governs the performance of an electric motor by applying the full line voltage to the motor terminals. 

Tuesday, 19 November 2013








Q:Why Human body feel Electric shock ? n in an Electric train during running , We didnt feel any Shock ? why?

A:Unfortunately our body is a pretty good conductor of electricity, The golden rule is Current takes the lowest resistant path if you have insulation to our feet as the circuit is not complete (wearing rubber footwear which doing some repairs is advisable as our footwear is a high resistance path not much current flows through our body).The electric train is well insulated from its electrical system.

Sunday, 17 November 2013

About Diode

An Ideal Diode should have Zero resistance in the forward bias and an infinitely large resistance in reverse bias.

Friday, 15 November 2013

OSCILLOSCOPE

Oscilloscope is widely used for measurement of time-varying signals. Any time you have a signal that varies with time - slowly or quickly - you can use an oscilloscope to measure it - to look at it, and to find any unexpected features in it
.

Thursday, 14 November 2013

STEPPER MOTOR

Stepper motor is the electrical machine which act upon input pulse applied to it. it is one type of synchronous motor which runs in steps in either direction instead of running in complete cycle.so, in automation parts it is used.

Friday, 4 October 2013

What is Flip Flop:



A bistable multivibrator. A circuit which has two output states and is switched from one to the other by means of an external signal (trigger).


Thursday, 3 October 2013

How to Design Heat sink for IGBT?


Any fined aluminum extrusion with a flat smooth surface can be used then your IGBT is mounted on it with a layer of silicon grease in-between, but remember the mounting surface is also your collector, if your heat sink is going to touch other metal parts it is beter to electrically insulate the IGBT with a silicon insulator strip and insulating sleeves for the mounting screws, then the heat sink can be mounted on a box that is fitted with a cooling fan with the fins inside the box, else it can be mounted open with the fins in a vertical position for natural airflow over the fins


Monday, 30 September 2013

Fleming Right Hand Rule:



Fleming Right Hand Rule:
As per Faraday’s law of electromagnetic induction, whenever a conductor moves inside a magnetic field, there will be an induced current in it. If this conductor is forcefully moved inside the magnetic field, there will be a relation between the direction of applied force, magnetic field and the electric current. This relation among these three directions, is determined by by Fleming Right Hand Rule



Wednesday, 25 September 2013

Operational Amplifier


An operational amplifier (op-amp) is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op-amp produces an output potential (relative to circuit ground) that is typically hundreds of thousands of times larger than the potential difference between its input terminals.



A proportional-integral-derivative controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control systems. A PID controller calculates an "error" value as the difference between a measured process variable and a desired setpoint. The controller attempts to minimize the error by adjusting the process control inputs.



Friday, 20 September 2013

DC Motor



A DC motor is a mechanically commutated electric moto powered from direct current (DC). The stator is stationary in space by definition and therefore the current in the rotor is switched by the commutator to also be stationary in space. This is how the relative angle between the stator and rotor magnetic flux is maintained near 90 degrees, which generates the maximum torque.


Thursday, 19 September 2013

Induction Motor



An induction or asynchronous motor is an AC motor in which current is induced in the rotor winding by the magnetic field of the stator winding, by electromagnetic induction.


INFRARED SENSOR:


An infrared sensor is an electronic device that emits and/or detects infrared radiation in order to sense some aspect of its surroundings. Infrared sensors can measure the heat of an object, as well as detect motion.



Saturday, 14 September 2013

SOLENOID VALVE:



The media controlled by the solenoid valve enters the valve through the inlet port (Part 2 in the illustration above). The media must flow through the orifice (9) before continuing into the outlet port (3). The orifice is closed and opened by the plunger (7).
The valve pictured above is a normally-closed solenoid valve. Normally-closed valves use a spring (8) which presses the plunger tip against the opening of the orifice. The sealing material at the tip of the plunger keeps the media from entering the orifice, until the plunger is lifted up by an electromagnetic field created by the coil.

1. Valve Body
4. Coil / Solenoid
7. Plunger
2. Inlet Port
5. Coil Windings
8. Spring
3. Outlet Port
6. Lead Wires
9. Orifice



R.O. (Reverse Osmosis) system:



Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane. This membrane-technology is not properly a filtration method. In RO, an applied pressure is used to overcome osmotic pressure, a colligative property, that is driven by chemical potential, a thermodynamic parameter. RO can remove many types of molecules and ions from solutions and is used in both industrial processes and in producing potable water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be "selective," this membrane should not allow large molecules or ions through the pores (holes), but should allow smaller components of the solution (such as the solvent) to pass freely.


Thursday, 12 September 2013

LEVEL SENSOR:



Level sensors detect the level of substances that flow, including liquids, slurries, granular materials, and powders. Fluids and fluidized solids flow to become essentially level in their containers (or other physical boundaries) because of gravity whereas most bulk solids pile at an angle of repose to a peak. The substance to be measured can be inside a container or can be in its natural form (e.g., a river or a lake).


Wednesday, 11 September 2013

What is IGBT ?




The insulated-gate bipolar transistor or IGBT is a three-terminal power semiconductor device primarily used as an electronic switch and in newer devices is noted for combining high efficiency and fast switching. It switches electric power in many modern appliances: Variable-Frequency Drives (VFDs), electric cars, trains, variable speed refrigerators, air-conditioners.




Tuesday, 10 September 2013

How a clamp meter works:

How a clamp meter works:


In electrical and electronic engineering, a current clamp or current probe is an electrical device having two jaws which open to allow clamping around an electrical conductor. This allows properties of the electric current in the conductor to be measured, without having to make physical contact with it, or to disconnect it for insertion through the probe. Current clamps are usually used to read the magnitude of asinusoidal current (as invariably used in alternating current (AC) power distribution systems), but in conjunction with more advanced instrumentation the phase and waveform are available. Very high alternating currents (1000 A and more) are easily read with an appropriate meter; direct currents, and very low AC currents (milliamperes) are more difficult to measure.