As equipment gets older, the potential for parts failures increases. The older the generator the more difficult it may be to source replacement parts. Some manufacturers go out of business. Some manufactures will only continue to produce spare parts for a period of time. When their parts inventory is exhausted it may be impossible to repair the unit. Or, retrofitting the equipment may not be worth the expense.
Reliability, Repairs and Maintenance
Emergency generators are installed for very good reasons, to back up critical electrical needs. If proper maintenance is being performed and failures are popping up regularly the confidence in the equipment to operate when needed erodes. The more critical the need, the more reliable the emergency generator needs to be.
The costs associated with repairs and the risk of unreliable equipment will ultimately outweigh the price of a new generator system.
Older generators should also receive a regular load bank test to insure the integrity of the entire system to carry its name plated load. As equipment ages or facility upgrades are made that could reduce the operating characteristics of the equipment the generator may not be able to handle its intended load.
Increased Capacity Needs-
As buildings age new equipment may be installed. This new equipment may require increased demands on the generator system. Any time loads are added to a building that needs to be backed via the emergency generator; a load study should be completed to insure that the generator can continue to operate as intended. If the load study shows the existing generator can handle the additional load you can be assured that your generator is capable of doing its job when you need it. If not you will either need to shed other loads or consider a larger generator system.
Increased need for operational knowledge-
Modern generators and electrical switchgear have abilities to communicate their status. In critical applications remote monitoring and control may become desirable. Many modern generators also have the ability to tie into building management systems giving facility managers much better data about their equipment.
Engine exhaust and noise emissions may become critical for an application. This could result from local code requirement enforcement to providing a better operating environment to the people that are situated close to an operating generator.
Modern engines emit significantly lower exhaust emissions than their predecessors. A desire to reduce exhaust emissions can be derived for many reasons including changing local requirements, EPA regulations limiting run time and a company’s desire to be identified as a “green” company.
Noise is also considered an undesirable effect from operating a generator. Modern enclosure designs can significantly reduce noise levels.
In the case of diesel generators fuel storage can be an issue. Diesel fuel can deteriorate over time and cause performance issues with engines.
Diesel fuel storage can also be influenced by local regulations or the local Fire Marshall. In some cases it may be desired to extend the potential run time of the generator in the event that long power outages may occur. Local requirements may limit the amount of diesel fuel that can be stored on site.
In recent years natural gas fueled or Bi-Fueled (operates on a combination of diesel and natural gas) generators in larger size ranges have become commercially viable. A desire to move to natural gas can be a motivation.
Long Term Budgets
Replacing a generator can be expensive. As part of a long term capital improvement project the generator system can be replaced as budgets may allow.
In almost all cases a capital investment in a generator system can last for many, many years. As time and requirements take a toll on existing equipment it may make sense to modernize the emergency generator system. In critical applications it is imperative to insure a well-functioning backup solution that can be managed as appropriate by the facilities management team. Sometimes it makes sense to look at replacing old equipment.
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Generator is a machine that converts mechanical energy into electrical energy. It works based on principle of faraday law of electromagnetic induction. The faradays law states that whenever a conductor is placed in a varying magnetic field, EMF is induced and this induced EMF is equal to the rate of change of flux linkages. This EMF can be generated when there is either relative space or relative time variation between the conductor and magnetic field. So the important elements of a generator are:
- Magnetic field
- Motion of conductor in magnetic field
Working of Generators:
Generators are basically coils of electric conductors, normally copper wire, that are tightly wound onto a metal core and are mounted to turn around inside an exhibit of large magnets. An electric conductor moves through a magnetic field, the magnetism will interface with the electrons in the conductor to induce a flow of electrical current inside it.
The conductor coil and its core are called the armature, connecting the armature to the shaft of a mechanical power source, for example an motor, the copper conductor can turn at exceptionally increased speed over the magnetic field.
The point when the generator armature first starts to turn, then there is a weak magnetic field in the iron pole shoes. As the armature turns, it starts to raise voltage. Some of this voltage is making on the field windings through the generator regulator. This impressed voltage builds up stronger winding current, raises the strength of the magnetic field. The expanded field produces more voltage in the armature. This, in turn, make more current in the field windings, with a resultant higher armature voltage. At this time the signs of the shoes depended on the direction of flow of current in the field winding. The opposite signs will give current to flow in wrong direction.
Types of Generators:
The generators are classified into types.
- AC generators
- DC generators
These are also called as alternators. It is the most important means of producing electrical power in many of the places since now days all the consumers are using AC. It works based on principle of the electromagnetic induction. These are of two types one is induction generator and other one is synchronous generator. The induction generator requires no separate DC excitation, regulator controls, frequency control or governor. This concept takes place when conductor coils turn in a magnetic field actuating a current and a voltage. The generators should run at a consistent speed to convey a stable AC voltage, even no load is accessible.
Synchronous generators are large size generators mainly used in power plants. These may be rotating field type or rotating armature type. In rotating armature type, armature is at rotor and field is at stator. Rotor armature current is taken through slip rings and brushes. These are limited due to high wind losses. These are used for low power output applications. Rotating field type of alternator is widely used because of high power generation capability and absence of slip rings and brushes.
It can be either 3 phase or two phase generators. A two-phase alternator produces two completely separate voltages. Each voltage may be considered as a single-phase voltage. Each is generated voltage completely independent of the other. The three-phase alternator has three single-phase windings spaced such that the voltage induced in any one phase is displaced by 120º from the other two. These can be connected either delta or wye connections. In Delta Connection each coil end is connected together to form a closed loop. A Delta Connection appears like the Greek Letter Delta (Δ). In Wye Connection one end of each coil connected together and the other end of each coil left open for external connections. A Wye Connection appears as the letter Y.
These generators are packaged with an engine or turbine to be used as a motor-generator set and used in applications like naval, oil and gas extraction, mining machinery, wind power plants etc
Advantages of AC Generator:
- These Generators are generally maintenance free, because of absence of brushes.
- Easily step up and step down through transformers.
- Transmission link size might be thinner because of step up feature
- Size of the generator relatively smaller than DC machine
- Losses are relatively less than DC machine
- These Generator breakers are relatively smaller than DC breakers
DC generator is typically found in off-grid applications. These generators give a seamless power supply directly into electric storage devices and DC power grids without novel equipment. The stored power is carries to loads through dc-ac converters. The DC generators could be controlled back to an unmoving speed as batteries tend to be stimulating to recover considerably more fuel.
Classification of DC Generators
D.C Generators are classified according to the way their magnetic field is developed in the stator of the machine.
- permanent-magnet DC generators
- Separately-excite DC generators and
- Self-excited DC generators.
Permanent magnet DC generators do not require external field excitation because it has permanent magnets to produce the flux. These are used for low power applications like dynamos. Separately-excite DC generators requires external field excitation to produce the magnetic flux. We can also vary the excitation to get variable output power. These are used in electro plating and electro refining applications. Due to residual magnetism present in the poles of the stator self-excited DC generators can able to produce their own magnetic field ones it is started. These are simple in design and no need to have the external circuit to vary the field excitation. Again these self-excited DC generators are classified into shunt, series, and compound generators.
These are used in applications like battery charging, welding, ordinary lightening applications etc.
Advantages of DC Generator:
- Mainly DC machines have the wide variety of operating characteristics which can be obtained by selection of the method of excitation of the field windings.
- The output voltage can be smoothed by regularly arranging the coils around the armature .This leads to less fluctations which is desirable for some steady state applications.
- No shielding need for radiation so cable cost will be less as compared to AC.
A diode is an electrical device or component with two electrodes (an anode and a cathode) through which electricity flows – characteristically in only one direction (in through the anode and out through the cathode). Diodes are generally made from semiconductive materials such as silicon or selenium – substances that conduct electricity in some circumstances and not in others (e.g. at certain voltages, current levels, or light intensities).
What is LED Lighting?
A light-emitting diode is a semiconductor device that emits visible light when an electrical current passes through it. It is essentially the opposite of a photovoltaic cell (a device that converts visible light into electrical current).
Did You Know? There is a similar device to an LED called an IRED (Infrared Emitting Diode). Instead of visible light, IRED devices emit IR energy when electrical current is run through them.
How Do LED Lights Work?
It’s really simple actually, and very cheap to produce…which is why there was so much excitement when LED lights were first invented!
The Technical Details: LED lights are composed of two types of semiconducting material (a p-type and an n-type). Both the p-type and n-type materials, also called extringent materials, have been doped (dipped into a substance called a “doping agent”) so as to slightly alter their electrical properties from their pure, unaltered, or “intrinsic” form (i-type).
The p-type and n-type materials are created by introducing the original material to atoms of another element. These new atoms replace some of the previously existing atoms and in so doing, alter the physical and chemical structure. The p-type materials are created using elements (such as boron) that have less valence electrons than the intrinsic material (oftentimes silicon). The n-type materials are created using elements (such as phosphorus) that have more valence electrons that the intrinsic material (oftentimes silicon). The net effect is the creation of a p-n junction with interesting and useful properties for electronic applications. What those properties are exactly depends mostly on the external voltage applied to the circuit (if any) and the direction of current (i.e. which side, the p-type or the n-type, is connected to the positive terminal and which is connected to the negative terminal).
Application of the Technical Details to LED Lighting:
When an light-emitting diode (LED) has a voltage source connected with the positive side on the anode and the negative side on the cathode, current will flow (and light will be emitted, a condition known as forward bias). If the positive and negative ends of the voltage source were inversely connected (positive to the cathode and negative to the anode), current would not flow (a condition known as reverse bias). Forward bias allows current to flow through the LED and in so doing, emits light. Reverse bias prevents current from flowing through the LED (at least up until a certain point where it is unable to keep the current at bay – known as the peak inverse voltage – a point that if reached, will irreversibly damage the device).
While all of this might sound incredibly technical, the important takeaway for consumers is that LEDs have changed the lighting landscape for the better, and the practical applications of this technology are almost limitless.
You may have heard that you should be performing maintenance tasks on your generator at least once a year. Maybe you have fallen behind and forgotten about your generator for a few years. You may be wondering why generator maintenance is so important. Keep reading to find out the benefits to performing generator maintenance tasks.
1. Keeps your generator running when you need it most
You most likely have a generator on your property to use in the event of an unexpected power outage. Of course, you want your generator to be working when you need it most. When the power goes out unexpectedly, that is the last time you would want to find out there is an issue with your generator. If you perform generator maintenance tasks you will ensure that your generator will run when you need it.
2. Prevents fuel problems
Without proper maintenance generators are more susceptible to fuel problems like algae build up on the fuel system, clogged fuel injectors, and dead batteries. These types of problems can even ruin your generator itself if they are let go for too long.
3. Saves you money in the long run
Although ignoring generator maintenance may save you a few bucks in the short-term, if you ignore maintenance for too long you will end up with costly repairs in the long run. You might even have to replace your whole generator unit.
4. Keeps your generator running for longer
A generator can be a large expense, and one you don’t want to make too often. By keeping your generator properly maintained you will be able to keep your generator running smoothly for longer than if you ignored maintenance tasks.
5. Increases efficiency
If you do have to run your generator, of course you would want it to run efficiently as possible. Generator maintenance tasks help your generator to reach its highest efficient potential.
Overall, generator maintenance will help to keep your generator in mint condition for years to come. This in turn, will save you time and money.
By Dorit Sasson
A generator can last for decades but it needs proper maintenance. Just like it’s important to eat healthy and exercise, a generator also needs maintenance to prevent it from breaking down. The better the maintenance, the longer your generator will function without the need for extensive repairs, which can translate into serious cash from purchasing expensive parts or even replacing the whole unit. Read on for seven top maintenance tips to ensure that your electrical generator is safe and ready to go when the power runs out.
Purchase a warranty or backup generator
This may seem pretty self-explanatory, but investing in a warranty might be the best thing to protect yourself when power runs out as generators aren’t cheap. Get to know the coverage; it might be full or partial. Investing in a back-up generator can also help control your home insurance costs as well.
Invest in a cover or an enclosure
Electricity is susceptible to water and the slightest rainfall might damage a part that might cost a pretty penny. Depending on whether your generator is a standby model or portable, you’ll want to invest in either a cover or an enclosure. Another suggestion is to build a generator garage similar to that of a doghouse for a portable generator.
Prevent motor burn-out
Use heavy-duty cords for less voltage use which can also prevent premature burn-out. Lighter cords increase the voltage. And since generators are noisy, you might be better off investing in a longer cord for uninterrupted sleep.
Power up your generator every three months
Manufacturers recommend running generators every three months for about 30 minutes to charge the battery for the electric starter. The last thing you’ll want is to discover that your electric starter isn’t working in time of need.
Fill up your tank
Avoid damaging your generator by keeping your tank filled with gas. When a generator runs out of gas, they stop power while the electrical load in your home will suck the magnetic field from the generator itself.
Keep oil and filters plentiful
The last thing you want to be doing is shopping for a new oil or filter during a long power outage, so keep a supply of oil and filters.
Do your homework
You don’t want to purchase a generator that will exceed the maximum capacity that your generator is able to put out. Be sure to read the ratings before buying a generator — there’s the higher “maximum” or “starting” rating or the “rated” or “continuous” watts. If you buy a generator for the higher power level, it will only work for a short time and at that level. But at the end of the day, that generator won’t extend its running capacity, and off you’ll be — running to find a new generator.
As you can see, a generator can be a lifesaver in times of prolonged periods of power outages. And when you take care of your generator, it gives you and your family the right peace of mind.
Generators are useful appliances that supply electrical power during a power outage and prevent discontinuity of daily activities or disruption of business operations. Generators are available in different electrical and physical configurations for use in different applications. In the following sections, we will look at how a generator functions, the main components of a generator, and how a generator operates as a secondary source of electrical power in residential and industrial applications.
How does a generator work?
An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output.
It is important to understand that a generator does not actually ‘create’ electrical energy. Instead, it uses the mechanical energy supplied to it to force the movement of electric charges present in the wire of its windings through an external electric circuit. This flow of electric charges constitutes the output electric current supplied by the generator. This mechanism can be understood by considering the generator to be analogous to a water pump, which causes the flow of water but does not actually ‘create’ the water flowing through it.
The modern-day generator works on the principle of electromagnetic induction discovered by Michael Faraday in 1831-32. Faraday discovered that the above flow of electric charges could be induced by moving an electrical conductor, such as a wire that contains electric charges, in a magnetic field. This movement creates a voltage difference between the two ends of the wire or electrical conductor, which in turn causes the electric charges to flow, thus generating electric current.