Motors

Most motors in control applications are just regular DC motors. A few are AC, and a few are true servomotors.

A true servo motor is optimized for high speed control systems. Specifically, you want fast linear response. To get this, they are typically somewhat high in cost, relatively low armature inertia, high torque (to give good acceleration). Often have marginal cooling (i.e. not rated for high duty cycle).

Electromagnetic Induction

Electromagnetic induction is the production of a potential difference (voltage)

]across a conductor when it is exposed to a varying magnetic field.

Michael Faraday is generally credited with the discovery of induction in 1831


Faraday's law of induction is a basic law of electromagnetism predicting how a 

magnetic field will interact with an 

electric circuit to produce an electromotive force (EMF). It is the fundamental 

operating principle of transformers, 

inductors, and many types of electrical motors, generators and solenoids.

Photodiode

A photodiode is a type of photodetector capable of converting light into either current or voltage, depending upon the mode of operation.[1] The common, traditional solar cell used to generate electric solar power is a large area photodiode.

How a proximity sensor works?

How a proximity sensor works :

A proximity sensor is a type of sensor which detects the presence of nearby objects called target without any physical contact. There are different types of proximity sensors such as inductive proximitysensor, capacitive proximity sensor, ultrasonic proximity sensor, photoelectric proximity sensor. Depending on the type of technology used proximity sensor emits an electromagnetic or electrostatic field, or a beam of electromagnetic radiation (infrared, for instance), and looks for changes in the field or return signal when target comes closer to the face of sensor.

There are different kinds of proximity sensors. They are

Capacitive proximity sensor
Inductive proximity sensor
Photoelectric proximity sensor
Ultrasonic proximity sensor

The advantages of the non contact proximity sensors are:

No physical contact required with the target to be detected, therefore, no moving parts so no friction and wear out.
Fast switching characteristics
Unlimited number of switching cycles since there is no mechanical contact
Can work in harsh conditions
Any type of target material can be detected.
A proximity sensor is used in many applications such as in mobile phones and for level sensing. In Iphone proximity sensor is used to deactivate the touch screen when the phone comes near to the face.

Resistance Temperature Detectors (RTD)

Resistance Temperature Detectors (RTD)

as the name implies, are sensors used to measure temperature by correlating the resistance of the RTD element with temperature.

RTDs are relatively immune to electrical noise and therefore well suited for temperature measurement in industrial environments, especially around motors, generators and other high voltage equipment.

Type

Pt 100, 200, 500, 1000,
copper 50,53. etc

Element size (MI)

Wire wound ceramic encapsulated
Wire wound Glass encapsulated
Thin film ceramic encapsulated

Connection

2, 3, 4 wire

Accuracy
Class A, B 1/2, 1/3, 1/5, 1/10 DIN

Charging a Capacitor

When a battery is connected to a series resistor and capacitor, the initial current is high as the battery transports charge from one plate of the capacitor to the other. The charging current asymptotically approaches zero as the capacitor becomes charged up to the battery voltage. Charging the capacitor stores energy in the electric field between the capacitor plates.

Shockley Diodes

Shockley diodes are curious devices, but rather limited in application. Their usefulness may be expanded, however, by equipping them with another means of latching. In doing so, each becomes true amplifying devices (if only in an on/off mode), and we refer to these as silicon-controlled rectifiers, or SCRs.
The progression from Shockley diode to SCR is achieved with one small addition, actually nothing more than a third wire connection to the existing PNPN structure

VACCUM CIRCUIT BREAKER:

A vacuum circuit breaker is such kind of circuit breaker where the arc quenching takes place in vacuum. The technology is suitable for mainly medium voltage application. For higher voltage Vacuum technology has been developed but not commercially viable. The operation of opening and closing of current carrying contacts and associated arc interruption take place in a vacuum chamber in the breaker which is called vacuum interrupter. The vacuum interrupter consists of a steel arc chamber in the centre symmetrically arranged ceramic insulators. The vacuum pressure inside a vacuum interrupter is normally maintained at 10 – 6 bar.

Types of Circuit Breaker

It depends what circuit you are making. 
Circuit breakers come in different 'ratings' and so are chosen according to the power demands of the circuit you have.
You don't choose a circuit for a circuit breaker as such, you choose a circuit breaker according to what circuit you have made.
There are several type of circuit breakers now a day we are using these are as follows:

1. M.C.B. (Miniature circuit Breaker)
Rating : 1, 2, 4, 6, 10, 16, 20, 25, 32, 63 Amperes

2. M.C.C.B. (Molded case circuit Breaker)
Rating : 10, 16, 20, 25, 32, 63, 100, 200, 250, 400 Amperes.

3. A.C.B. (Air Circuit Breaker)
Rating : 400, 800, 1000, 1200, 1500, 1800, 2000 Amperes.

4. A. B. Switch (Air Breaker)
used in High tension line.

5. SF6 Breaker (Contact break in the Sf6 medium)
used in High tension line.

mcb internal circuit shown in figure ....

What is a Solenoid Valve?

What is a Solenoid Valve? How does a Solenoid Valve Work?

Solenoid valves are electrically actuated mechanical systems that control the flow of substances like liquids and gases. Solenoid valves are commonly used on automotive transmissions.The solenoid valve uses an electric current which moves the solenoid. This pulls a piston preventing it from stopping the flow of air and fluid. The valve will need a constant flow of electrical current to remain open because when there is no current flow, the electromagnetic field scatters and the valve returns to its original position.

What is AC series motor?

An AC series motor is a special type of motor, which has been designed to operate on either AC or DC power. This type of motor is also called universal motor. An advantage of the AC series motor is, this type of motor is designed to provide high starting torque and as it has very compact design so high running speeds are produced. The basic construction of an ac series motor slightly differs from the construction of a dc series motor. AC series motor has low speeds for large loads and high speeds for light loads. This type of motor is widely used in small home appliances like blower, grinder and power tools like drill machine etc.

Use of Single & 3-phase and HVDC

Most transmission lines use high-voltage three-phase alternating current (AC), although single phase AC is sometimes used in railway electrification systems. High-voltage direct-current (HVDC) technology is used for greater efficiency in very long distances (typically hundreds of miles (kilometres)), or in submarine power cables (typically longer than 30 miles (50 km)).
Electricity is transmitted at high voltages (110 kV or above) to reduce the energy lost in long-distance transmission. Power is usually transmitted through overhead power lines

Function of AC Drives

AC Drives are also known as Inverters, Variable Speed Drives (VSDs), Variable Frequency Drives (VFDs) and Frequency Convertors. 

AC Drives are used to control AC Induction motors; the most common motor technology used in industry. The motors are rugged, require very little maintenance and can easily be manufactured with high environmental protection.

If an AC motor is connected directly to the mains supply the motor will accelerate quickly and then rotate at a fixed speed which is dependant upon the electrical supply frequency and the motor design.

What is a thermocouple sensor?

What is a thermocouple sensor?
A thermocouple is a sensor for measuring temperature. It consists of two dissimilar metals, joined together at one end. When the junction of the two metals is heated or cooled a voltage is produced that can be correlated back to the temperature. The thermocouple alloys are commonly available as wire.

What are the different thermocouple types?
A thermocouple is available in different combinations of metals or calibrations. The four most common calibrations are J, K, T and E. There are high temperature calibrations R, S, C and GB. Each calibration has a different temperature range and environment, although the maximum temperature varies with the diameter of the wire used in the thermocouple

AC DRIVES

AC Drives are also known as Inverters, Variable Speed Drives (VSDs), Variable Frequency Drives (VFDs) and Frequency Convertors. 

AC Drives are used to control AC Induction motors; the most common motor technology used in industry. The motors are rugged, require very little maintenance and can easily be manufactured with high environmental protection. 

If an AC motor is connected directly to the mains supply the motor will accelerate quickly and then rotate at a fixed speed which is dependant upon the electrical supply frequency and the motor design.

What happen if AC Supply willl given to a DC Motor ?

It depends on the construction of the motor. If the field winding is connected in series with the armature winding, the motor is like a universal motor and will probably operate normally. If the field winding is connected in parallel with the armature, the motor will not run, but will draw current, make noise and get hot.
Shunt wound DC motors are not suitable for AC operation because the difference in inductance between the armature and the field causes a relative phase shift between the armature current and the field current. For a DC motor to operate with AC current, the armature and field currents must reverse at exactly the same time, as they do when the windings are connected in series. For reasonably good performance, the cores need to be laminated and the brush position needs to be set to 90 degrees.

VOLTAGE REGULATOR

VOLTAGE REGULATOR:

A voltage regulator is designed to automatically maintain a constant voltage level. A voltage regulator may be a simple "feed-forward" design or may include negative feedback control loops. It may use an electromechanical mechanism, or electronic components. Depending on the design, it may be used to regulate one or more AC or DC voltages.
Electronic voltage regulators are found in devices such as computer power supplies where they stabilize the DC voltages used by the processor and other elements. In automobile alternators and central power station generator plants, voltage regulators control the output of the plant. In an electric power distribution system, voltage regulators may be installed at a substation or along distribution lines so that all customers receive steady voltage independent of how much power is drawn from the line.

Wave Length Frequency of Rays

Wave Length Frequency of Rays

INFRARED:Infrared (IR) light is electromagnetic radiation with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 700 nanometres (nm) to 1 mm. This range of wavelengths corresponds to a frequency range of approximately 430 THz down to 300 GHz,[1] and includes most of the thermal radiation emitted by objects near room temperature. Infrared light is emitted or absorbed by molecules when they change their rotational-vibrational movements. The existence of infrared radiation was first discovered in 1800 by astronomer William Herschel.

ELECTROMAGNETIC SPECTRUM:

Name Wavelength Frequency (Hz) Photon Energy (eV)

Gamma rayless than 0.01 nm more than 10 EHz 124 keV – 300+ GeV

X-Ray 0.01 nm – 10 nm 30 EHz – 30 PHz 124 eV – 124 keV

Ultraviolet 10 nm – 380 nm 30 PHz – 790 THz 3.3 eV – 124 eV

Visible 380 nm–700 nm 790 THz – 430 THz 1.7 eV – 3.3 eV

Infrared 700 nm – 1 mm 430 THz – 300 GHz 1.24 meV – 1.7 eV

Microwave1 mm – 1 meter 300 GHz – 300 MHz 1.24 µeV – 1.24 meV

Radio 1 mm – 100,000 km 300 GHz – 3 Hz 12.4 feV – 1.24 meV

Third Digit Multiplier

 In CAPACITOR GUIDE, first two digits provide the value in Pico-Farads and third digit Multiplier will be as follows: 
0 1
1 10
2 100
3 1,000
4 10,000
5 100,000

Advantages of Synchronous Motors

Advantages of Synchronous Motors:

1. These motors can be made to operate at leading power factor and thereby improve the pf of an industrial plant from one that is normally lagging to one that is close to unity.

2. This motor operates at a constant speed, irrespective of load, from no-load to full load.

3. Electromagnetic power varies linearly with the applied voltage.

4. These motors can be constructed with wider air gapes than induction motors making them mechanically better.

5. Efficiency of operation is usually high, especially in the low speed and unity power factor ranges.

Disadvantages of Synchronous Motors:

1. These motors cannot be used for variable speed jobs as there is no possibility of speed adjustment

2. It requires external source for supplying dc excitation

3. It cannot be started under load, the starting torque being zero

4. It has a tendency to hunt.

5. It may fall out of synchronism and stop when over-loaded.

6. Collector rings and brushes are required.

7. For some applications these motors are not desirable as for driving shafts in small work-shops having no power available for starting and in cases where frequent starting or strong starting torque is required.

PROGRAMMABLE LOGIC CONTROLLER

PROGRAMMABLE LOGIC CONTROLLER

Before the PLC, control, sequencing, and safety interlock logic for

manufacturing automobiles was mainly composed of relays, cam timers,

drum sequencers, and dedicated closed-loop controllers. Since these

could number in the hundreds or even thousands, the process for

updating such facilities for the yearly model change-over was very time

consuming and expensive, as electricians needed to individually rewire

relays to change the logic.

AC DRIVE

An AC drive is a device that is used to control the speed of an electrical motor, either an induction motor or a synchronous motor. AC drives are also known by various other names such as adjustable speed drives (ASD) or variable frequency drives (VFD) . Industrial machinery is often driven by electrical motors that have provisions for speed adjustment. Such motors are simply larger, more powerful versions of those driving familiar appliances such as food blenders or electric drills. These motors normally operate at a fixed speed.

If speed control is required, that controller is called a (variable speed) AC drive. AC drives are used in a wide variety of industrial applications.