Electromechanical Relays and Contactors

Electromechanical Relays and Contactors

Relays of the electrical contacts close and open for the operation of other devices. The reason for their usage is because they are cost-efficient when compared to their proportional electronic switches. There are also few relays that are superior in quality to devices that are solid-stat. For instance, relay circuits in output and input are isolated electrically unlike solid-state devices. Relays have many contacts electronically which is isolated from one another. Also, electromechanical relays are now smaller available in surface-mount packages and PCB-mount packages that are best suited for automatic soldering.

There are many advantages of electromechanical relays out of which one is, it has low contact resistance in correspondence to solid-state switches. The contact capacitance is much lower which in turn benefits circuits of high-frequency.

Electromechanical Relays varies in three prime ways

The first type of electromechanical relays that differ from solid-state switches is the relay coils that are known for their high inductivity. The inductance value is also not persistent. After energization, the inductance is quite low and gradually increases as the current approaches and closes the relay armature.

Secondly, the switching time of the relays is much longer. The reasons stated are the coil inductance, armature mass, and contact structures.

Third, it is known to produce high-voltage transients after it is reenergized. The transients can be reduced to an acceptable level by protective circuits but will delay the relay drop.

Reed Relay is limited in quantity by the coil size

It comprises of reed switches in an operating coil. It can be of any configuration type but is limited in quantity because of its coil size. The manufacturers limit the size of the coil to handle maximum switches of 12 standards. Additional contacts can be obtained but the relays must be connected parallel.

Mercury-wetted contact relays consist of glass switches

It comprises glass switches of one or more, while the coil encircles it. The original resistance is maintained within 1 m all around their life.

For repeated interrupting and establishing circuits of electric power, contractors are used. The contractors are defined by magnetic and electronic.

Electromagnetic contractors are achieved by means of electromechanical. They break and make the power circuits to load as light, electric furnaces, capacitors, transformers, heaters, etc.

The magnetic contractor comprises of the movable armature and a stationary core. The contractors are designed horizontally, while some have pivoted or hinged clapper magnets. They are available in 600 V, 110 V, 240 V, 380V, 220 V, 480 V, 440 V, and 500 V.

Working Of Inverters And Functions Of Relays

Working Of Inverters And Functions Of Relays

Working Of Inverters And Functions Of Relays

An inverter is one of the useful devices which are used as a power backup for uninterrupted power supply. It is mainly required when there are frequent power outages in your locality. The inverter offers the supply of constant power to the AC voltage when the AC main is not available. There are several popular UPS manufacturers in Chennai. To understand the functioning of an inverter, you must understand its operation under various situations.

Detailed workings of an Inverter is explained below for a better understanding.

AC Power- Available

When there is power available, and thus reaches to the relay and battery charging section of the inverter. The supply would come from the AC mains, and the entire load would be from line voltage. This voltage is also offered to charge the inverter where it is converted into a DC voltage. When the battery or inverter is wholly charged the charging process is stopped.

AC Power-Not Available

When the main current supply is not available, the oscillator circuit present inside the inverter generates and drive signal called MOS drive signal. This signal is amplified in the section where the driver is present, and it reaches the output of the inverter. The switching operation takes place with MOSFETs and transistors, and they are connected as a primary winding of the inverter transformer. When the MOS signal is generated and the switching device turns ON and OFF at the rate of 50HZ. This results in an AC current of 220V at the inverter transformer. This is available in the output socket through a change over relay.

The circuit of an inverter can able to manage various situations like overload, low battery, etc. Thus it can handle the inverter condition standby or running mode. Therefore it is possible to switch the battery to OFF or charging mode. The various working modes can be indicated with the help of the LED lights that are provided in the inverter.

How Does Relay work?

Relays and its Working PrincipleIt is basically an electromagnetic switch which is used in the circuit of an inverter. When a single power controls a circuit, then this component is made use of to turn on and off a particular circuit. Various industrial application devices make use of relays for its effective functioning.

The basic principle behind the working of a relay is electromagnetic switching. Some of the essential parts of the relay are electromagnet, armature, switch point contact, spring.

The power is offered to the electromagnet with the help of a control switch. When constant current starts flowing, it energizes the electromagnet which creates an intensified magnetic field.

The two basic operations with relays are low voltage and high voltage applications.

The above is the essential operation of an inverter and the functions of a relay in an inverter. The knowledge about the workings of inverter and relays would be of great use.

Read More : Benefits Of Using Reed Switch Technology


The Excellence of Electromechanical Switches

The Excellence of Electromechanical Switches

The Excellence of Electromechanical Switches

Advancement of technology does not always mean that the equipment which was used earlier has become redundant. In the case of EMRs, this statement is correct. Relay technology has undergone substantial changes in the past 3 to 4 decades. The advent of specialized modern pieces of equipment has changed the landscape completely.

Electromagnetic Magnetic Industrial Switches

Class is permanent

Electromechanical relays are still in demand because of the full range of practical applications for which they can be utilized. Whenever technicians want relays that can serve them in case of general needs, they opt for electromechanical relays.They are also known as electromagnetic switches because they use energy in this form to operate.

Transmission of signals using EMRs

The use of electromechanical relays has not undergone any decrease despite the arrival of solid state relays. The ability of electromechanical relays to transmit signals efficiently has allowed them to stand the test of time. Their durability also makes them a viable option for most technicians. When there is a need to test automated equipment, all expert mechanics and engineers prefer using electromechanical relays.

EMRs are forever

It is safe to say that EMRs are here to stay for a long time to come. You must bear in mind that the resistance, as well as the capacitance of EMRs, make them unique in many ways. Their efficiency at switching loads allows them to be used in many machines. Operating electromechanical relays is slightly complicated, but their effectiveness makes them accessible.

SSRs vis-a-vis EMRs

The capacitance of SSRs is nowhere near the value possessed by electromechanical relays. Their resistance is also not up to the mark for many purposes. It is evident that solid state relays are valuable in their way for a small range of utilities. An expert will always select the most suitable equipment keeping in view the requirements of the project. So, you must understand that comparing them will not give any practical solutions.

Apt tools for suitable times

The truth is that their applications are separate with some common elements. The aim of an electrical engineer should be to make optimum usage of both of these excellent pieces of equipment rather than attempting to draw parallels between them. SSRs are different switches because they provide ease in operation. They allow technicians to switch the load in minimal time. EMRs are brilliant because of their efficient modus operandi even though they take more time to finish switching.

Read More : Use of Electromagnetic Relays For Technicians

Use of Electromagnetic Relays For Technicians

Use of Electromagnetic Relays For Technicians

Uses of Electromagnetic Relays

If you are an electrician or an electrical engineer, you will come across electromagnetic relays at some point of time when you are at work. Even mechanical engineers must have an understanding of all the concepts relevant to EMRs. Skills of working with solid state relays can also prove to be valuable to you.So, you must keep learning and growing as professionals in these fields.

Things To Know About Electromagnetic Relays : 

Knowledge is power

You must get to know about the various pros and cons of using electromagnetic relays in different situations. At the same time, you should know about all the probable scenarios in which electromagnetic relays can prove to be valuable as well as practically useful. High-quality differential protection is one of the most vital contributions that electromagnetic relays provide.

EMRs to protect AC and DC

Electromagnetic relays are efficient when it comes to protecting the alternating current components of any machine. They are equally effective at preserving the direct-current parts of multiple pieces of equipment. If you use solid state relays for the same purposes, you may not get the kind of results you want. Solid state relays have a different Arena of applications. But they are not very useful for general purposes. Hence, if you want one device to take care of multiple situations, then choosing electromagnetic relays will be a viable option.

Using the right tool at the appropriate time

All engineers, as well as technicians, must understand the optimum situation when they can use solid state relays or electromagnetic relays. If your scheme has protective relaying, then using electromagnetic relays in the form of auxiliaries will be an excellent maneuver. Understanding the modus operandi of these devices will help you excel in your field.

Power matters a lot

It is also essential that the electromagnet in your EMR is powerful and in a decent condition. Poor quality material can be detrimental, and you will not get the kind of results which you desire. Hence, you must always select devices of the highest possible quality.

The basics of electromagnetic radiations

Creation of electromagnetic waves is essential if you want energy to flow form of electromagnetism. Relays are switches which utilize electromagnetic energy in a wide range of electrical devices. You must get to know about the various pieces of equipment which operate based on power in the electromagnetic form. If you do an online search, you will get all the answers that you seek.

Read More : New Applications Seek Better Relays

Electromagnetic Relay – Its Working And Types

Electromagnetic Relay – Its Working And Types

Relays operated using an electromagnetic action are known as electromagnetic relays. The latest Electromagnetic Relays coming up in the market are the ones that are based on microprocessors. Even after the most recent changes, the role of electromagnetic relays is constant. There is still a lot of time till the traditional electromagnetic relay gets replaced by the static relays. Let us try to know more about the different types of electromagnetic relays we have got. There are predominantly three types of electromagnetic relays comparison, magnitude measurement, and ratio measurement.

Various working principles of a relay there are further classifications

  • Attraction armature type relay: Straightforward construction and are used mostly as auxiliary relays. It is used as measuring relay most of the time.
  • Induction cup type relay: It is a disc type relay that is utilized where quick operation along with the polarization effect is required. The number of poles can differ depending on the windings of the relay.
  • Power Relay: It has four pole induction that produces a flux that is proportional to the voltage. It can be designed to create the highest possible amount of torque.
  • Reactance type induction cup relay: It is made by manipulating the coil arrangements for either voltage or current. Pure reactance can be measured by this type of relay.
  • Balanced Beam Relay: It is known as the variant of amateur type relay. However, the field of application of the two is entirely different. These are becoming obsolete day by day.
  • Moving Coil Type Relay: It is a polarized DC coil relay that is extremely sensitive in its operation. It provides accurate measurements in o time.

This was all about various types of electromagnetic relay devices. In transistors and radios, electromagnetic relays have been sued like forever. The main feature about it includes the need of low resistance and its nature to remain isolated from the control signal(physically). There are a few drawbacks of these kinds of relays as well. There are a few big sized relays, and sometimes the coils require a considerable amount of current. Sometimes the operation is slowed due to the switching speed. One has to make sure that the contacts are regularly maintained.

One might ask if a relay is similar to a transistor. Well, the answer is no, though the results required somewhere match, they are not the same thing. Transistors can sometimes perform like a relay. Earlier with the invention of transistors, the concept of television came in to picture. However, relays are used in more number of devices today due to its excellent functionality. An electromagnetic relay can produce a relatively high amount of current even when a low current is passed through it. Therefore it finds a lot of use in alarming devices, safety devices, and other quality control devices. There is much more to explore about this brilliant device. However, the use of microprocessor embedded relays can be a massive breakthrough in the future to come.

Read Also : Simple Explanation About Hybrid Relay