If you can't explain it simply, then you don't know it well enough. — Albert Einstein

What Are Frequency Inverters?

Frequency inverters are used to adapt the power coming from source into a piece of equipment like an electric motor. There are two types of current – direct current (DC) and alternating current (AC) and both work differently. Inverters were invented to allow Alternating Currents or Direct Currents to be used together, even though they are very different, to produce the energy needed to power items.
Lenze SMD inverter

AC and DC current

Direct Current is the simplest one to explain. The current all runs in the same direction, making a ‘chain’ or ‘circuit’ of power. Direct Current is used in standard circuit products like torches where the batteries are inserted and complete the circuit allowing the product to work.
Alternating Current works differently. This power supply changes direction about 50 to 60 times a second. This can also be written as 50 – 60 Hz a second. When the two types are brought together the electrons in both the currents are combined so the Alternating Current is continually ‘hit’ by the direct current and ultimately makes it stand still within the cables, forcing the energy through from source to equipment.

Electric Motors

Different motors need different currents to work but the electricity supplied is usually Alternating Current. This means, an inverter needs to break the current between the Alternating Current and the Direct Current and mix it up, otherwise the motor will just not work. The inverters job is to convert the power to what is needed. It works like a switch, alternating the supply on a regular basis to about 50 – 60 Hz a second, to produce the energy needed to power the motor.
There are DC motors and AC motors, but both need both types of current to work completely. When a motor is first switched on, the power generated can start off at speed with no way of controlling it. Introducing the opposite current via an inverter, allows the user to vary and control the speed, making the equipment more useable. Electric motors need inverters to adjust the current being supplied so the user can control it, making the motor more effective in its running and usage.

Selecting a Supplier

As you can tell, inverters are complicated pieces of equipment and as such, you need to find a supplier who actually understands them. Find a company, such as Bearing Boys, who can offer the best in the market, built from reliable companies such as the German firm Lenze.
The inverters need to be able to convert what you need them to while also offering options of having different phases. Inverters can come in all shapes and sizes with single-phase input, 3-phase input and 3-phase output. Having variations in the range mean you can discuss options to suit your needs.
Variations do not stop at outputs; you may need one that can withstand moisture in the air or work areas that are washed down on a regular basis. Keep an eye out for these products if that is what you need. No point spending the money before discovering it will blow the first time you clean the area. Ultimately, you need the products to be affordable, so value for money is top of the list.
Purchase from a company such as Bearing Boys that has the knowledge and support to help you make the right choices for you and not for them.

Insulators used in overhead power lines

Overhead line insulators

It is obvious that if overhead power lines are not properly insulated from their support poles/towers, the current will flow towards the ground through the poles/towers which also become hazardous. Of course, the power line won't even work in that case! Hence, overhead power lines are always supported on insulators mounted on their support poles/towers.
Overhead line insulators should have the following properties:
  • high mechanical strength in order to withstand the conductor load, wind load etc.
  • high electrical resistance in order to minimize the leakage currents
  • high relative permittivity of insulating material so that the dielectric strength is high
  • high ratio of puncture strength to flashover
Most commonly used material for overhead line insulators is porcelain. But glass, steatite and some other special composite material may also be used sometimes.

Types of insulators used in overhead power lines

For the successful operation of power lines, proper selection of insulators is very essential. There are several types of overhead line insulators. Most commonly used types are
  • Pin type insulators
  • Suspension type insulators
  • Strain insulators
  • Shackle insulators

Pin type insulators

Pin type insulators or pin insulators are popularly used in electric distribution systems up to 33 kV voltage level. They are secured on the cross arms of the pole to carry power lines. There is a groove on the upper end of a pin insulator for housing the conductor. Conductor wire is passed through this groove and secured by binding with the same wire as of conductor.

pin insulator
A pin insulator is usually made from porcelain, but glass or plastic may also be used in some cases. As pin insulators are almost always employed in open air, proper insulation while raining is also an important consideration. A wet pin insulator may provide a path for current to flow towards the pole. To overcome this problem, pin insulators are designed with rain sheds or petticoats. Beyond operating voltage of 33kV, pin insulators become too bulky and uneconomical.

Insulation failure

An insulator must be properly designed so as to withstand mechanical as well as electrical stresses. Electrical stress on insulator depends on the line voltage, and hence, proper insulators must be used according to the line voltage. Excess electrical stress can break-down the insulator either by flash-over or puncture.
  • Flash-over: In insulator flash-over, electrical discharge occurs by forming an arc between the line conductor and the insulator pin (which is connected to the cross-arm). The discharge jumps through the air surrounding the insulator following the shortest distance. In case of a flash-over, the insulator continues to act according to its designed capacity unless it gets destroyed due to the excess heat.
  • Puncture: In case of insulator puncture, electrical discharge occurs from conductor to pin through the body of the insulator. Sufficient thickness of porcelain (or the insulator material) must be provided to avoid a puncture breakdown. When such breakdown is involved, the insulator is permanently damaged.
  • Safety factor of insulator: The ratio of puncture strength to flash over voltage is called as safety factor. It is desirable to have high value of safety factor so that a flash-over takes place before the insulator gets punctured. For pin type insulators, the value of safety factor is about 10.

Suspension insulators

As it is already mentioned above, pin insulators become too bulky an uneconomical beyond 33 kV. So, for voltages higher than 33 kV, suspension insulators are used. A suspension insulator consists of a number of porcelain discs connected to each other with metal links in the form of a string. Line conductor is suspended at the bottom end of the suspension string which is secured to cross-arm of the tower. Each disc in a suspension insulator string is designed for a low voltage, say 11 kV. The number of discs in a string depends upon the working voltage.

suspension string insulator

Advantages of suspension insulators

  • Each unit of disc is designed for a low voltage, say 11 kV. Hence, depending upon the working voltage, desired number of discs can be connected in series to form an insulator string suitable for particular voltage.
  • If any of the discs in insulator string is damaged, it can be replaced easily. Replacement of the whole string is not required.
  • In case of increased demand on the line, the line voltage can be increased and the additional insulation required for the raised voltage can be easily provided by adding the desired number of discs in the insulator strings.
  • As the line conductors are suspended by suspension strings, they run below the earthed cross-arms of the towers. This arrangement provides partial protection from lightning.
  • The suspension arrangement provides greater flexibility to the line. Suspension insulators are allowed to swing so that they can take up the position where mechanical stresses are minimum.

Strain insulators

strain insulator

At a dead end of a transmission line or at a corner or sharp curve, the transmission line is subjected to a great tensile load. In order to sustain this great tension, strain insulators are used at dead ends or sharp corners. For high voltage transmission lines, stain insulator consists of an assembly of suspension insulators. In this case, the suspension string is arranged horizontally and the insulator discs are in vertical plane. Two or more suspension strings can be assembled in parallel to sustain greater tensions. For low voltage lines (less than 11 kV), shackle insulators are used as strain insulators.

Shackle insulators

shackle insulator
Shackle insulators are used in low voltage distribution lines as strain insulators. A shackle insulator can be used vertically as well as horizontally and it can be directly fixed to a pole with a bolt or to the cross arm. However, the use of such insulators is decreasing after increasing the use of underground cables for distribution purpose.

How Do You Make Your New Home's HVAC System More Energy Efficient?

how to make your home's HVAC system more energy efficient
A lecture on increasing the energy efficiency of HVAC system. Source: http://www.ashrnews.com/

It is a part of the common knowledge that HVAC system is an essential and an inevitable item of each and every residential structure, from single family homes to institutions such as educational or health institutions, to business facilities. Since the society is struggling with economic problems and everyone, both common people and business persons, are constantly striving to save as much money as possible and to make sound investments, creating HVAC systems that are more energy efficient is a must. This is a statement on which everyone would undeniably agree. Besides taking care of saving money, people should also bear in mind that their responsibility is to preserve our precious environment that is alarmingly endangered, especially in the past few years or even decades. Having taken all these facts and statements into account, it appears obvious that finding ways to make new home’s HVAC system more energy efficient is supposed to be considered as the top challenge by all the business persons, and all the experts in general, who are engaged in the field of this system through either creating, producing, selling setting them up or restoring them. Nonetheless, business persons should be the first ones to recognize it as their challenge and therefore try hard to produce an HVAC system that will save both money and environment. This article aims to underline the most successful recently discovered way to achieve such a noble goal.

[Also read: Top 10 Benefits Of Upgrading Your Home HVAC System]
Customers of the HVAC themselves should contribute to the usage of the system getting more efficient by following certain rules such as to change or clean the filters regularly, tune up the HVAC equipment every year, use natural lighting and other natural sources like moving air to control temperature, repair air leaks with a variety of materials such as expanding foam, etc. Nonetheless, business persons who title HVAC system as their field of work and expertise should definitely consider and take up certain techniques that will help them obtain more energy efficient systems. Besides, those who have undergone an HVAC training should also see developing HVAC systems the way they will become more efficient as their responsibility.
It is not a secret that customers who use the HVAC system have noticed the examples of greater expenditures and reported them to the business persons engaged in the field. To clarify this, if the system is filtering the air from the outside and then warming it up or cooling it for space within the building, it makes the whole process quite expensive, and such an expenditure could be decreased by following certain steps for energy saving. An expert in the field, HPAC Engineering’s Hal Conick brought up the useful techniques of the company enVeird that might help HVAC system save energy through the program they created, which is called HLR (HVAC Load Reduction). What is the main benefit of this system? The benefit lays in the practice of using air that is already in the building, instead of taking up the expensive process of absorbing and filtering the air from the outdoors. In addition to that, HLR clears out the carbon dioxide as well as the organic gases from the inside of the building, thus providing the ones who use the facility with the constant circulation of fresh air. Returning to the fact that it uses the air from the indoors rather than absorbing the air from the outdoors, it might lead one to the conclusion that a system such as HLR is also extremely beneficial to the environment, as it does not waste extra sources. It would be interesting to explain more closely how the HLR system manages to get the indoors’ air back into circulation. Actually, it all seems quite simple – it is done by a special intelligent scrubber that appears to be quite efficient as well as eco-friendly.

[Also read: Watch out! Kitchen appliances can be dangerous if misused.]
Nevertheless, applying such an energy saving system is useful but by no means easy. According to the specialist mentioned above, respected Hal Conic, HLR process is “easy to describe, but not easy to do” (Source: http://contractingbusiness.com/commercial-hvac/system-hopes-make-hvac-systems-more-efficient-less-expensive). What this expert stresses as the most difficult regarding the usage of HLR is the very fact that removing carbon dioxide from a building is an utterly complex process. He then claims that this gas is not easy to capture within a closed building without a great expenditure. Therefore, coming up with the idea and managing to produce a system such as HLR that provides HVAC system with a possibility to reduce the amount of the energy spent to absorb the air that will be heated and cooled within the facility is a remarkable challenge and a remarkable success. Although, according to Hal Conick, technology has so far not found many solutions for making HVAC system more efficient, cost-effective and eco-friendly and therefore business persons engaged in this field should take it as a challenge and strive to create more processes that resemble HLR in the future. Thus, more efficient practices such as this one will appear and improve the efficiency of HVAC system.

Author: My name is Helena, I am a young student and also a creative and versatile writer. I am ambitious, witty and always up for challenges...as well as for new writing tasks!

Watch Out! Kitchen Appliances Can Be Dangerous If Misused

More than half of the accidental house fires start in the kitchen. Most often homeowners don’t put much thought into how to use their major kitchen appliances on a day-to-day basis. Using them in the right way is necessary to avoid mishaps and accidents. According to the statistics of a survey, an electrical incident kills around 16 Australians every week. So you should always put safety first to avoid any accident that can turn out to be a fatal one. Government records show that the largest number of accidents reported are caused by electricity flaws in homes due to people misusing electrical cooking appliances, including food processors, microwaves, electric stoves, ovens, etc.
In case you need 24/7 emergency electrician to fix any type of electrical defect in your home, you will be contented to know that there are various experts who can help you in this task. Here are certain aspects that can help you for sure to avoid the chances of an accident taking place due to mishandling of electrical appliances.

Hot Heat

Appliances that generate heat must be handled with caution, especially the oven and stove that are frequently used in the kitchen. One among all safety rules that need to be followed in a kitchen is to always be prepared to put out a fire. This means that fire extinguisher should be handy for out-of-control blazes. Keep the baking soda to extinguish grease fires. Remember that using water will only cause a grease fire to spread.
Contact burn is the most common injury linked to the oven and stove, so keeping a first aid kit nearby is always advisable. Moreover, using thick and dry potholders to handle hot items and exercising extra care when children are around is a sound and safe decision. Turing the handles of pots and pans toward the centre of a stove, since children can pull them down if handles face outward.

[Also read: Benifits of upgrading your home HVAC system]


Dishwashers are considered as a significant appliance used to simplify day-to-day tasks. They also produce a good amount of heat, albeit no flames. The most important safety risk associated with them is the steam that escaped at the time of the heat dry cycle. Yes! Steam can be more dangerous than flames, as it can lead to severe injuries. Furthermore, delicate and stemware glass dishes should be used carefully because they can break inside the machine.
You may cut yourself if you don’t pay attention the time you unload the unit, it can be really dangerous. And if you are unloading a machine after a heat dry cycle, some of them may be too hot to handle specially, if they are made of metals.

Cook or Bake Safely

Using microwave for cooking or banking includes certain key safety precautions, so you need to pay extra attention to avoid any kind of accident. You should only use microwave-safe dishes and containers than metal dishes. Nowadays, these machines are designed to prevent radiation leaks, damage to doors and seals may make this possible. Inspecting microwave timely can be a great way to avoid accidents in a kitchen.
You should be extra careful while heating liquids. If you overheat a liquid, these super-heated ones can explode out of their containers, leading to a scalding spray.
It’s not only the electrical appliances that can be dangerous, even the sockets or wire can also be the reason behind an accident. So, you can’t miss other aspects such as faulty wiring or other problem delivering power to your kitchen. You can contact an experienced and skilled electrician offering after-hours electrical services. Just look for the best one to offer an extra protection to your home.

Skin effect and Proximity effect

What is skin effect?

When an Alternating Current flows through a conductor, it is not distributed uniformly throughout the conductor cross-section. AC current has a tendency to concentrate near the surface of the conductor. This phenomenon in alternating currents is called as the skin effect. Due to the skin effect, current is concentrated between the outer surface of the conductor and a level called as the skin depth (skin depth is shown by ẟ in the following figure). If the frequency of AC current is very high, the current is restricted to a very thin layer near the conductor surface. Skin effect increases with increase in the frequency.
Due to skin effect, the effective cross-section of the conductor through which the current flows is reduced. Consequently, the effective resistance of the conductor is slightly increased.

skin effect

The cause of skin effect

Imagine a solid conductor split into a large number of strands, each strand carrying a small part of current. The inductance of each strand will vary according to its position. Strands located at the center would be surrounded by a greater magnetic flux and, therefore, will have a larger inductance than those near the surface. Higher inductance (and hence, higher reactance) of the inner strands causes the alternating current to flow through the strands having lower reactance, i.e. near the surface.
The skin effect depends upon the following factors:
  • Conductor material: Better conductors and ferromagnetic materials experience higher skin effect
  • Cross-sectional area of the conductor: skin effect increases with increase in the cross-sectional area
  • Frequency: increases with increase in the frequency
  • Shape of the conductor: skin effect is lesser for stranded conductors than solid conductors

Proximity effect

When two or more conductors carrying alternating current are close to each other, then distribution of current in each conductor is affected due to the varying magnetic field of each other. The varying magnetic field produced by alternating current induces eddy currents in the adjacent conductors. Due to this, when the nearby conductors carrying current in the same direction, the current is concentrated at the farthest side of the conductors. When the nearby conductors are carrying current in opposite direction to each other, the current is concentrated at the nearest parts of the conductors. This effect is called as Proximity effect. The proximity effect also increases with increase in the frequency. Effective resistance of the conductor is increased due to the proximity effect.

proximity effect
Skin effect and proximity effect both are absent in case of DC currents, as frequency of DC current is zero.
[Also read: Corona effect]