3- Phase Induction Motor

         Industrial Star Delta Starter for a 3-Phase Induction Motor

Objectives of Star-Delta Technique Motor Starter are:

Reduce high starting current and along these lines forestall motor from overheating

Provide over-burden and no-voltage assurance

3- Phase Induction Motor

Star Delta Starter:

In star delta starting, the motor is connected in STAR mode throughout the starting period. When the motor reached the required speed, the motor is connected in DELTA mode.

Star Delta Motor Control Power Circuit

Star Delta Motor Control Power Circuit

Components of a Star-Delta Starter:

Contractors: The Star- Delta starter circuit comprises of three contractors: Main, star and delta contractors. The three contractors are solicited to unite the motor winding first in star and afterward in delta.

Timer: The contactors are regulated by a timer incorporated with the started.

By any chance if star and delta contactors are actuated at the same time, the motor will be damaged.

Thermal overload relay: A thermal over-load relay is likewise consolidated into star-delta control circuit to ensure the motor from intemperate heat which might expedite motor finding fire or wearing out. In the event that the temperature goes past a preset quality, the contact is open and power supply is cut in this manner ensuring the motor.

Working of Star-Delta Starter:

At first the primary contractor and the star contactors are shut. After a time interval the timer signs to the star contactor to head off to the open position and the primary, delta contactors to head off to the shut position, accordingly structuring delta circuit.

Hence, the line current drawn by the motor at starting is decreased to one-third as contrasted with starting current with the windings associated in delta. Likewise, since the torque advanced by an induction motor is corresponding to the square of the applied voltage; star- delta starter decreases the starting torque to one- third of that possible by immediate delta starting.

The timer controls conversion from star connection to delta connection. A timer in star delta starter for a 3-phase motor is intended to do the move from star mode, utilizing which the motor runs on a decreased voltage and current and produces less torque – to the delta mode indispensable for running the motor at its full power, utilizing high voltage and current to transform a high torque.

Terminal Connections in Star and Delta Configurations:

L1, L2 and L3 are the 3-phase line voltages, which are given to primary contractor. The main motor coils are U, V and W is shown in figure. In star mode of motor winding, the primary contractor associate the mains to essential winding terminals U1, V1 and W1.the star contractor shorts the auxiliary winding terminals U2, V2 and W2 as indicated in figure. Notwithstanding when the primary contractor is shut supply arrives at terminals A1, B1, C1 and consequently the motor winding are energized in star-mode.

The timer is initiated in the meantime moment when star contactor is energized. After the timer achieves the specified time period, the star contactor is de-energized and delta contactor is energized.

Induction motor winding terminals connected in star and delta configuration

Induction Motor Winding Terminals Connected in Star and Delta Configuration

The point when delta contractor closes, the motor winding terminals U2, V2 and W2 get associated with V1, W1 and U1 individually through the shut contacts of primary contractor. That is for delta association, fulfilling end of one winding is to be joined with beginning end of the other winding. The motor winding are reconfigured in delta by supplying line voltage L1 to winding terminals W2 and U1, line voltage L2 to winding terminals U2 and V1; and line voltage L3 to winding terminals V2 and W1, as indicated in figure.3- Phase Induction Motor most of uses to Industrial work.

Electrical Safety Devices

Electrical Safety Devices - Using Your Electrical Panel

Your electrical board is an electrical welling gadget that close down an electrical circuit at whatever point it is utilizing excessively present, and may cause fire or electrical stun. Numerous individuals just consider taking a gander at their board when one of their electrical circuits quits working. Nonetheless, the shrewd occupant or mortgage holder will have thought ahead, and named the circuits in the board box, with the goal that it is clear which switch or wire controls which circuits in their living arrangement.

When you have found your electrical board, open it up and check whether it contains wires, or circuit breakers. Most present day habitations utilize breakers, yet some more seasoned homes may even now have intertwines. In the event that the power has been stopped to one of your electrical circuits, here's a little home electrical repair you can do to reestablish it:Electrical safety device is save electrical system and our life.

Electrical Safety Devices 

Utilizing a Fuse Box:

At the point when a breaker "blows", the current in its circuit has turned out to be sufficiently expansive to dissolve a thin metal strip inside it. At the point when this happens, obviously, the current can't be reestablished until the point that the breaker has been supplanted with another one. Continuously utilize another circuit that has an indistinguishable rating from the one you are supplanting. Utilizing a 20 amp circuit to supplant a 15 amp combine is exceptionally risky, as it would empower much too high a current to exist before blowing.

Before you supplant the breaker, make certain to kill every single electrical machine on its circuit, especially those that you think may have made the wire blow. And furthermore, for your wellbeing, divert from the ace switch for the breaker box, just to make sure you don't get stunned when putting in the better one.

Utilizing a Breaker Box:

At the point when a lot of current goes through an electrical switch, it "outings", and prevents the current from streaming. The breaker change goes to a nonpartisan position among ON and OFF. To reestablish control, you should simply perplex the change to, and after that back to ON - yet DON'T DO IT YET! To begin with, kill all machines in the circuit.

Reestablishing the current:

Play Judas on, either by tossing the ace switch or the electrical switch change back to the on position. On the off chance that the wire passes or the breaker clicks over immediately, you have a significant issue with the wiring some place in the electrical circuit. Call a circuit tester promptly!

In the case of everything appears to be OK, turn on the machines in the circuit one by one. In the event that one of them blows the circuit once more, it is causing too high a current. There could be a short in the apparatus, and you should get it repaired or supplanted. Or on the other hand when you turned it on, it could have included excessively of a heap to what's now turned on. All things considered, consider having an electrical repairman introduce another electrical switch with a higher rating.

In the event that things are great in the electrical board, however an outlet still doesn't have control, turn on its switch on the off chance that it has one. In the event that it isn't exchanged, at that point you should check its wiring, or bring in an electrical repairman to do it for you

Cables

Home Theater Cables: How Do I Know Which Ones I Need?

You have many options to choose from when it comes to home theater cables, the most popular of which are HDMI cables and component video cables, and with so many choices and price points on the market, the task of finding the right ones can seem a little daunting.

Cables

The audio/video cables you choose to use with your home theater system can have a tremendous impact on your overall listening or viewing experience. So what differentiates one type of cable from another, and why are some cables significantly more expensive than others? This buying guide will answer these questions and more, helping you make an informed decision about your cable needs.

In short, cables carry the audio or video information from your receiver, DVD player or other device to your speakers and/or television. Using low quality cables is likely to degrade the quality of the final output, such as a movie or album. If you have a high-end HDTV and a top-of-the-line home theater system, most audio professionals will tell you it's worth it to spend a little extra money on quality HDMI, component video and home theater cables in order to optimize the performance of your television and home theater system.

To put this into another context, imagine installing an expensive water filtration system under your sink, running a water line from the filtration system to your high-end refrigerator/ice maker, and then using mildewed tubing for the water line that connects the two. Even though you have the best filtration system and in-door water and ice service, using dirty old water lines contaminates the end product and doesn't give you the outcome you were looking for.

Now that you have a basic understanding of the role cables play, let's look at the different types of home theater cables. The most common cables you may encounter are HDMI cables, which are digital, and video component cables, which are analog. We'll also cover a few other types of cables.

HDMI Cables: HDMI stands for High Definition Multimedia Interface.HDMI cables have the ability to deliver the highest quality sound and picture in a single cable. The use of HDMI cables is a good way to avoid compromising sound quality, which often occurs when converting and reconverting digital to analog, due to HDMI's use of a 19-pin connector that transfers digital audio and video signals between components. HDMI cables are surround-sound compatible, and are the only cables that support up to eight channels. Industry experts expect HDMI to become standard in coming years.

Component Video Cables: Component video cables are your best non-digital option for high definition video. Component cables look identical to composite cables, but the signal quality is much higher. This is because these cables break the video signal into three cables, thus maximizing both image clarity and sharpness. Most component cables are color-coded, making them easy to install, but note that component video cables are not backward-compatible with composite, so you will want to make sure your equipment will work with component video connectors before making your purchase. You will want to look for cables that use copper center conductors and double- or triple-shielding to help preserved the video signal. Secure-fitting gold-plated connectors are another element to look for when shopping for component video cables.

DVI Cables: DVI stands for Digital Video Interface, and these cables offer a fairly new type of connection that offers superior video quality. They work by maintaining the video signal in its digital form from its source to the final output, such as your television or projector, and this results in extremely high quality picture. This technology is still under development, so there are no universal standards yet for DVI cables.

F-Type Coaxial Cables: These are probably the most common and least desirable cables on the market. They work by "modulating" both the audio and video signal onto a single cable, which diminishes the quality of the signal. The F-Pin connections used by these cables are only capable of supplying mono audio, not stereo. Component video, S video, or composite video cables would all be better choices than F-Type Coaxial Cables when it comes to the quality of the final output.

Composite Video Cables: These cables are typically considered a step up from standard coaxial cables and feature RCA connectors. Similar to F-Type cables, composite video cables carry all the video signals on a single cable, resulting in a lower quality output. Often composite cables will be used in conjunction with analog audio cables.

S-Video Cables: S-Video cables are considered a significant improvement over composite video cables because they break the video signal into two parts. Inputs for S-video are found on most high-quality televisions and A/V components.

As you explore the world of home theater cables, you will probably find a few types of cables not discussed here, but this overview should serve as a good introduction to the most common types of cables. Most people end up selecting HDMI cables or component video cables for their home theater systems, but if you need assistance you can work with an A/V professional to ensure you get the right cables for your specific needs and equipment.

I am a hands-on business owner, professional systems integrator, and long-time technology buff. I have received certifications from MEDIA, Speaker Craft, Control, and other organizations related to audio/video, low-voltage, and automation.

Vacuum Circuit Breaker

Vacuum Circuit Breakers: The Importance

Circuit breakers are electrical devices which are used in electrical panels. They monitor and control the amount of electricity that goes through the electrical wiring and are important to make sure that the electrical system of a house or any kind of facility is functioning properly. This is why when there is a circuitry problem, it is vital to check if the circuit breakers are causing it and if they need to be replaced.

Although a lot of individuals today automatically choose to buy new circuit breakers once they find out that the ones they have need to be replaced, more and more are realizing that buying used breakers might be the better option. This is because used breakers are actually just as good as new ones and are priced a lot cheaper. There are also plenty of places where you can buy them. Many online and offline stores have them and you would usually have a lot of options for the types of used breakers that you can purchase.

Vacuum Circuit Breaker

Have you ever heard about vacuum circuit breaker? This is one among various useful circuit breakers that work really well to deliver higher protection for electricity system in your home. This is a certain breaker that is used to provide higher protection for any electricity system in medium as well as high voltage circuits. Therefore, any risk of dangerous situations such as fire could be surely reduced.

Just like other types, this breaker works to break the circuit to stop electrical power flows through it. It will reduce the risk of fires, power surges, as well as some other dangerous problems that might emerge. Vacuum breaker has been used since around 1920 and nowadays many companies have manufactured this supply in better technology to provide higher safety.

There are two electrical contacts included in this certain breaker. One will be fixed and another will be movable. The movable contact will be pulled away from the fixed one in order to interrupt the flowing current when any dangerous situation occurs. The contacts are designed in vacuum to suppress arc. This will also function to ensure the circuit remains open, so it will not be powered.

Then what makes this kind of breaker important? Vacuumcircuit breaker will be perfect option since it is very durable and strong. Besides, this breaker is also designed to last for longer period of time. This is one of some reasons for people to choose this certain breaker for different requirements. However, if you are also interested to install this breaker in your electrical system, you need to check the rate of the product carefully. Make sure that your chosen breaker has suitable rate for your needs, since too low rated product will not work well for protection.

You will find this certain product in several different brands. Make sure to know well the requirement of your electrical system well before buying a certain product. Therefore, your selected breaker could bring proper protection to the electrical system.

There are many options to be your best preference when you are about to find ground fault circuit 

Water Transfer Pump

Using Water Transfer Pumps

There are many uses for water transfer pumps. You can use them in your business or at home. These water pumps are portable for your convenience. They can vary in price, size, and can come with an assortment of attachments and features. Many satisfied customers praise the results that their transfer pumps have helped them achieve. No job is too large or too small for this handy piece of equipment.

Water transfer pumps are devices that move water from one location to another. These tools can be used for many types of work including agriculture, light commercial or even residential. Some tasks they might be used for include draining shallow and flooded areas, watering the yard, and irrigation in agriculture. Transfer or clear water pumps are used specifically for clear water and should be kept free of debris and other blockage. This being said, choosing the correct pump for your needs is very important. You have to do research including online reading, talking to other pump owners, and talking to professionals who specialize in the sale of water transfer. There are different kinds based on the method they use to move the water.

There are many efficient, environmentally-friendly watertransfer pumps out on the market The Wayne 115V-310 GPH Portable Transfer Water Pump available at such hardware stores as Lowe's and Ace Hardware. It is generally priced from $74.00 - $120.00. It is a self-priming pump and includes a six foot suction hose and is plated in chrome-bronze. Another wonderful unit available at Ace Hardware is the Little Giant Pump Company Pool Cover Water Pump. It's generously priced at $63.99, is a manual pool cover pump, and is ideal for light household and yard jobs involving water transfer.

Water Transfer Pump

As you can see, many water transfer devices are time-saving and labor-saving tools that help a person perform otherwise difficult and time-consuming jobs. Why not do yourself a favor and purchase economical, easy-to-use water transfer equipment and save yourself time and physical pain from hard labor? Many satisfied customers have given wonderful reviews on the above mentioned products. Either these of a variety aof other water transfer pumps are waiting for you to purchase and put to good use.

Sango Zane covers more types of pumps, including specialized raw water pumps

Water pump is an important tool for a variety of residential, light commercial or agricultural tasks. Especially in the rural areas, it can play a very important role. Water pump can drain water from a basement or even from shallow flooded areas. It can also drain and fill the swimming pool and pond. Besides, it can be applied to meet irrigation requirements for agriculture. It can also be used in the construction. All in all, it has various usages.

There are also many types of water pumps, and each of them can serve a special purpose in a home or business. Although most of water pumps have similar performances and functions, you should still have to consider different aspects to choose the appropriate products for your own. For example, if you want to drain your hot tub or garden pond, you can choose transfer pumps which are made for clear water pumping and should be free of debris. In addition, they can also be used to drain shallow flooded areas and for lawn sprinkling. But if you want to buy a suitable pump for agricultural usage, you should choose high-pressure pumps which are designed to provide higher pressure at lower volumes because they can move water over long distances

How to Choose a Transformer

 Transformer

When choosing a transformer, there are two primary concerns: the load and the application. Several factors must be evaluated carefully while making the choice, to ensure that the needs of both primary concerns are met.

To use a cliché, it is typically a 'no-brainer' to choose smaller transformers. A unit with a kVA rating that is larger from the anticipated load can quickly be picked up. But if you are selecting a large unit for an electrical utility system, to be part of a large distribution network, you are typically making a much larger investment; thus the evaluation process is much more detailed and elaborate. With over 90 years of experience in this industry, Pacific Crest Transformers has put together a quick checklist to help you make your choice judiciously.

There are three major questions that influence your choice:

Does the chosen unit have enough capacity to handle the expected load, as well as a certain amount of overload?

Transformer

Can the capacity of the unit be augmented to keep up with possible increase in load?

What is the life expectancy of the unit? What are the initial, installation, operational, and maintenance costs?

Evaluation Factors

The cost and capacity of the transformer typically relate to a set of evaluation factors:

1.    Application of the Unit

Transformer requirements clearly change based on the application.

For example: in the steel industry, a large amount of uninterrupted power is required for the functioning of metallurgical and other processes. Thus, load losses should be minimized - which means a particular type of transformer construction that minimizes copper losses is better suited. In wind energy applications, output power varies a great extent at different instances; transformers used here should be able to withstand surges without failure. In smelting, power transformers that can supply constant, correct energy are vital; in the automotive industry, good short-term overload capacity is a necessary attribute. Textile industries, using motors of various voltage specifications, will need intermittent or tap-changing transformers; the horticulture industry requires high-performance units that suit variable loading applications with accurate voltage.

These examples serve to underline that type of load (amplitude, duration, and the extent of non-linear and linear loads) and placement are key considerations. If standard parameters do not serve your specific application, then working with a manufacturer that can customize the operating characteristics, size and other attributes to your needs will be necessary. Pacific Crest regularly builds custom transformers for unique applications.

2.    Insulation Type (Liquid-Filled or Dry Type)

While there is still debate on the relative advantages of the available types of transformers, there are some performance characteristics that have been accepted:

o    Liquid-filled transformers are more efficient, have greater overload capability and longer life expectancy.

o    Liquid-filled units are better at reducing hot-spot coil temperatures, but have higher risk of flammability than dry types.

o    Unlike dry type units, liquid-filled transformers sometimes require containment troughs to guard against fluid leaks.

Dry type units are usually used for lower ratings (the changeover point being 500kVA to 2.5MVA). Placement is also a crucial consideration here; will the unit be indoors serving an office building/apartment, or outdoors serving an industrial load? Higher-capacity transformers, used outdoors, are almost always liquid-filled; lower capacity, indoor units are typically dry types. Dry types typically come in enclosures with louvers, or sealed; varnish, vacuum pressure impregnated (VPI) varnish, epoxy resin or cast resin are the different types of insulation used.

Liquid-filled types: choice of filler material

The choice of filler material is usually based on factors that include temperature rating of the transformer, mechanical strength of the coils, dielectric strength of the insulation, expansion rate of the conductors under various loads, and resistance to thermal shock of the insulation system.

Liquid-filled types: temperature considerations

Using fluid both as an insulating and a cooling medium, liquid-filled transformers have rectangular or cylindrical forms when constructing the windings. Spacers are utilized between the layers of windings to allow the fluid to flow and cool the windings and core.

Within the sealed tank that holds both core and coils, the fluid flows through ducts and around coil ends, with the main heat exchange taking place in external elliptical tubes. For transformers rated over 5 MVA, radiators (headers on the top and bottom) are used for additional heat transfer. Modern paper insulation in liquid-filled units allows a 65ºC average winding temperature rise.

Dry type: temperature considerations

Dry type insulation provides dielectric strength and ability to withstand thermal limits. Temperature rise ratings are typically 150 ºC, 115 ºC, and 80 ºC, based on the class of insulation used (see box).

3.    Choice of Winding Material

Transformers use copper or aluminum for winding, with aluminum-wound units typically being more cost-effective. Copper-wound transformers, however, are smaller - copper is a better conductor - and copper contributes to greater mechanical strength of the coil. It is important to work with a manufacturer that has the capability and experience to work with either material to suit your specific requirement.

4.    Use of Low-Loss Core Material

Core choice is a crucial consideration, and core losses should be determined properly. Losses that occur in the core are due to hysteresis and eddy currents. High quality magnetic steel should be used so that hysteresis losses are reduced; laminated cores are chosen to minimize eddy current losses.

5.    Protection from Harsh Conditions

It is very important that transformer core, coils, leads and accessories are properly protected, especially when used in harsh environments. Liquid-filled transformers should be of sealed-type construction, automatically providing protection for the internal components. For highly corrosive conditions, stainless steel tanks can be employed. Some approaches to building dry-type transformers for harsh environments include cast coil units, cast resin units, and vacuum pressure encapsulated (VPE) units, sometimes using a silicone varnish. Unless the dry-type units are completely sealed, the core/coil and lead assemblies should be periodically cleaned, even in non-harsh environments, to prevent dust and other contaminant buildup over time.

s, thus augmenting the load capability of the transformer as well.

Generator

Choosing a Generator for Everyday Usage

When it comes to choosing a generator especially one that is needed for everyday use, over and above anything else you would need one that is highly reliable as well as being up to the job which you require it for. Cheap half-hearted efforts that you see being sold as a bargain in a large store probably would not be an ideal purchase.

Performance is vital as there is nothing worse than coming to depend on a particular appliance only to be let down in your real hour of need.

A diesel-powered version is probably not a good idea either as they tend to be exceptionally large which makes them a lot less portable than most other generators plus they are not really suited to the use of being an everyday generator unless you were thinking of powering a small office off of the beaten track on a daily basis.

So gas power is the way to go and looking at the higher end of the market to cure any reliability issues which means a fairly high wattage and horse power generator. The good thing about a larger model portable Generator is that it will be capable of powering several small items all at the same time or much larger items individually.

Generator 

Another big advantage with a modern-day generator is that even though they may have a high output and come with many gizmos and gadgets integrated for uninterrupted electricity flow and such like they certainly maintain a portable size.

Without knowing the specific requirements that you might require a generator for it is difficult to gauge a specific model, but if you go on the basis that a generator putting out about 8,000 watts will be able to power most of your electrically driven household items or singularly on the much larger items such as heating water etc. then you have an idea of what you can expect performance wise.

This gives you an engine size of about 400 to 500cc providing you with around 14-horsepower equivalent to about (8,000 watts). When you get to these levels it is important to know the run-time on a tank of gas and noise levels, although you will find most portable generators these days with these capabilities will probably incorporate some kind of noise distribution system or special muffler.

It makes sense to use a 400cc plus generator because this way you will have both the reliability and longevity that is required if you intend using it frequently or even every day. Anything less will just not be up to the job and will certainly not have anywhere near the power capabilities.

The really good thing is that once you have bought a generator with this type of ability you will probably never want to be parted from it, after all in an emergency situation or complete power outage it would be the backbone for stability.

Generator 

Gone are the days when owning a generator is considered a luxury, these days you can pick up some pretty impressive small powerhouses at very reasonable prices.

There are a few generator manufacturers that fit the bill so it is worth having a look around. The bottom line is that it is worth buying one that is bigger than you might need as this way you will have it for a much longer period and it will always provide you with more than enough power.

Finally, in order to get the best value for money you are better off buying online, not just your generator, but pretty much anything these days.

The Power Engineer Career Schooling Opportunities

Understudies can contemplate for various authentications and degrees in this energizing field. 

Picking up an instruction in electrical designing should be possible by enlisting in an authorize professional learning program. Understudies can pick up the aptitudes expected to enter the workforce arranged for their coveted vocation. Electrical building vocation tutoring openings incorporate mechanical autonomy, PCs, control frameworks, coordinated circuits, and substantially more. Degrees are accessible going from a partner to a doctorate level of training in the field.

*Associate Degree

Acquiring a certify relate level degree in this field should be possible by selecting in an assortment of professional and specialized projects. Understudies who wish to pick up a fast training and enter the workforce can do as such by submitting two years to their instruction. With preparing at this level understudies can look for work in interchanges, control, gadgets, computerization, and that's only the tip of the iceberg. Coursework may comprise of AutoCAD, microchips, specialized math, mechanical technology, modern gadgets, and numerous other related subjects. Understudies will have the capacity to plan for vocations as electrical designing professionals I, II, and III. Facilitating training should be possible at a lone ranger's level of study.

*Bachelor Degree

Understudies hoping to pick up a single guys degree in electrical building can do as such by finishing four long periods of preparing. Preparing will enable understudies to go into various energizing professions while work in PC programming, electrical circuits, thermodynamics, and considerably more. Coursework can incorporate the investigation of subjects, for example, computerized rationales, electromagnetic, control frameworks, control frameworks, and significantly more. With an instruction in these subjects understudies can seek after an assortment of vocations including venture build, electrical architect, outline design, test design, and numerous different callings. Preparing can enable understudies to look for work or seek after graduate degrees in the field.

Power Engineer

*Master Degree

Certify professional schools furnish understudies with the chance to pick up an experts degree in electrical building. Understudies can think about for various callings by finishing required coursework and preparing. Particular territories of study can incorporate computerized frameworks, hardware, and considerably more. Study will take into account work as research, test, undertakings, and application engineers. With certify ace level degree preparing understudies can go into their coveted profession with the fundamental abilities and learning.

*Doctoral Degree

Profession openings are accessible for the individuals who wish to go into the field of electrical designing. Understudies can consider courses in PC systems, propelled PC systems, science, electrical basics, and numerous other applicable courses. Conceivable vocations can incorporate functioning as specialists, teachers, and different callings. Preparing at this level will enable understudies to begin the vocation they had always wanted in this energizing field.

Licensed electrical building schools and universities are accessible to furnish understudies with the way to seek after an energizing profession. Accreditation is given by offices like the Accreditation Board for Engineering and Technology power engineer full accreditation gives verification that the instructive preparing system will offer understudies a quality training at their coveted level. Understudies can begin by enlisting in a licensed program today.