A diesel generator is the combination of a diesel engine with an electric generator that converts the mechanical energy to electrical energy. Diesel, gasoline and natural gas engines are commonly preferred to provide the mechanical energy.
The alternator is a rotating electrical machine that transforms rotational mechanical energy to electric energy. The system coupled with the diesel engine is a diesel generator. Diesel engine used as the driver source operates with diesel fuel and transforms chemical energy to mechanical rotation energy.
Electric energy generated by the diesel generator can control devices such as fuse, contactor, switch (circuit breaker) and induce load supply. Additionally, there are control and alarm units that measure and monitor the important parameters of the generator.
The main components of an electric generator can be broadly classified as follows:
• Fuel System
• Voltage Regulator
• Cooling and Exhaust Systems
• Lubrication System
• Battery Charger
• Control Panel
• Main Assembly / Frame
Standby power generators are most often used in emergency situations, such as during a power outage. It is ideal for applications that have another reliable continuous power source like utility power. It’s recommend usage is most often only for the duration of a power outage and regular testing and maintenance.
Prime power ratings can be defined as having an “unlimited run time”, or essentially a generator that will be used as a primary power source and not just for standby or backup power. A prime power rated generator can supply power in a situation where there is no utility source, as is often the case in industrial applications like mining or oil & gas operations located in remote areas where the grid is not accessible.
Continuous power is similar to prime power but has a base load rating. It can supply power continuously to a constant load, but does not have the ability to handle overload conditions or work as well with variable loads. The main difference between a prime and continuous rating is that prime power gensets are set to have maximum power available at a variable load for an unlimited number of hours, and they generally include a 10% or so overload capability for short durations.
The primary difference between kW (kilowatt) and kVA (kilovolt-ampere) is the power factor. kW is the unit of real power and kVA is a unit of apparent power (or real power plus re-active power). The power factor, unless it is defined and known, is therefore an approximate value (typically 0.8), and the kVA value will always be higher than the value for kW.
The power factor (pf) is typically defined as the ratio between kilowatts (kW) and kilovolt amps (kVa) that is drawn from an electrical load, as was discussed in the question above in more detail. It is determined by the generators connected load. The pf on the nameplate of a generator relates the kVa to the kW rating (see formula above). Generators with higher power factors more efficiently transfer energy to the connected load, while generators with a lower power factor are not as efficient and result in increased power costs. The standard power factor for a three phase generator is 0.8
An automatic transfer switch (ATS) transfers power from a standard source, like utility, to emergency power, such as a generator, when the standard source fails. An ATS senses the power interruption on the line and in turn signals the engine panel to start. When the standard source is restored to normal power the ATS transfers power back to the standard source and shuts the generator down.
Automatic Transfer Switches are often used in high availability environments such as data centers, manufacturing plans, telecommunication networks and so forth.
In general, most commercial generators can be converted from 60 Hz to 50 Hz. The general rule of thumb is 60 Hz machines run at 1800 Rpm and 50 Hz generators run at 1500 Rpm. With most generators changing the frequency will only require turning down the rpm’s of the engine. In some cases, parts may have to be replaced or further modifications made.
Larger machines or machines already set at low Rpm are different and should always be evaluated on a case by case basis. We prefer to have our experienced technicians look at each generator in detail in order to determine the feasibility and what all will be required.
For a safe installation, choosing a suitable generator location is important. You need to consider the warnings in the manual for correct and complete installation. For more information, you can contact Emsa generator. You need to consider the following factors when choosing and mounting area for the generator and follow the necessary implementation steps.
• Sufficient Clean Air Suction
• Sufficient Hot Air Discharge
• Suitable Exhaust Gas Discharge
• Levelled Concrete Base Construction or Levelled Concrete Area Identification
• Protection Against Undesired Weather Conditions (Sun, Heavy Rain and Snow etc.)
• Protection Against Negative Environmental Conditions (Excessive Dust, Humidity, Dampness etc.)
• Leaving At Least 1m Gap Around the Generator for Operation, Designing Entrance Door By Considering Possible Re-Location of the Genset from Installation Area
• Installation area should be selected in a way to avoid any workplace accidents caused by slipping and falling due to surface coating or oil discharge
• If the installation will be in the open area, the generator set should be protected from weather conditions and cabin-type genset should be used
If the generator is operated under low load, the lifecycle will decrease and serious damaged might occur.
This is especially more important in larger power.
Minimum permitted load for standby generators is 30% of the standby power.
If the generator is operated under no-load or low load, there might be:
• Corrosive damage on engine parts
• Decreased greasing quality due to thinning in greasing oil
• White smoke
• Oil or liquid leakage in the exhaust and air suction system
• Carbon accumulation on cylinder covers or exhaust manifold
The generator set tag specifies the suitable operation categories (Standby, Prime).
Using above these operating conditions will lead to the following problems:
• Decreased engine life
• Overheating in the engine
• Increased engine erosion
• Overhearing on alternator windings, isolation vulnerabilities
• Thinning in greasing oil and decreased oil pressure
Generators must be tested under load at least once in every 15 days by the operator for 10 minutes. If the generator will not be used for a long time, storage in the “Maintenance and User’s Handbook” should be done by the authorised service. After long-term storage, authorised service should commission the generator. This is also related to the scope of guaranty.
Generator sets can be paralleled for either redundancy or capacity requirements. Paralleling generators allows you to electrically join them to combine their power output. Paralleling identical generators will not be problematic but some extensive thought should go into the overall design based on the primary purpose of your system.
If you are trying to parallel unlike generators the design and installation can be more complex and you must keep in mind the affects of engine configuration, generator design, and regulator design, just to name a few.
Getting a generator that can handle all your power generation needs is one of the most critical aspects of the purchasing decision. Whether you are interested in prime or standby power, if your new generator can’t meet your specific requirements then it simply won’t be doing anyone any good because it can put undue stress on the unit and even damage some of the devices connected to it.
Determining exactly what size of generator to get is often very difficult and involves a number of factors and considerations.
To get more detailed information on this subject, please can contact us fee free.