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What are the two main types of timber?
The 2 main types of timber are Softwoods and Hardwoods.
What is life orientation?
Rising in Consciousness is the main interest of life. Like a universal consciousness.
What three main types of organic compounds are used in society?
The 3 main types of organic compounds used in society are alkanes, alkenes and alkynes
What are two main types of rocket engines?
The two main types of rocket engines are Solid fuel rocket engines and Liquid fuel rocket engines.
What is the main advantage of DC over AC for aircraft electrical power systems?
It doesn't have to be rectified. That's the ONLY advantage; the electrical systems in all but the smallest planes are 400Hz AC systems.
What are 2 types of skeletal systems?
The main types are endoskeletons and exoskeletons.
What are the 4 main types of economic systems?
the 4 main types of economic systems are: a market economy, a mixed economy, a planed economy, and a traditional economy
What are some different kinds of payroll systems?
The three main types of payroll systems are manual, software and external.
What are the main types of irrigation systems in India?
the main types of irrigation systms in India are wells and tube wells tanks canals dams and lakes.
What is the two main types of steering systems?
Worm gear and rack and pinion.
Two types of intonation?
As far as I know , there are two main intonation patterns in English: rising and falling intonations.
3 main types of economic systems?
capital resources, human resources, & natural resources
The two main types of root systems are .?
Tap root and Adventitious roots
List two different types of operating systems and briefly describe the main feature of each?
macintash and window
What are the main types of personnel employed in an information systems department?
project manager graphics designer chief programmer
Bus bar arrangements in sub station?
Burbars are the important elements in the electrical substation. Bus bars acts as nodal point in the substation which connects different incoming and outgoing circuits.Substations present in the power system performs various operations depends on the application such as stepping up the voltage, stepping down the voltage, high voltage transmission and switching stations to route the power to desired load center.Busbars in Substation:Busbars used in the substations are generally rectangular or circular cross section bars. These busbars can be either solid or hollow structures. Hollow circular cross section busbars are employes in EHV substations to reduce the corona effect.Switching Schemes:Switching schemes implies different methods employed to connect electrical circuits in the power system to transfer the electrical power in reliable manner. Switching schemes helps in deliver the electrical power to power system if any part of the system is faulty or under maintenance.Substations use different types of busbar arrangements or switching schemes depends upon the application, reliability of the supply and cost of installation. In every substations busbars plays a common role to connect different circuits. However switching is possible in the power system with the help of circuit breakers and isolators.Considerations for selection of busbar arrangement:Different types of busbar arrangements are employed based on the voltage, reliability of the supply, flexibility in transmitting power and cost. The other aspects considering in designing the busbars arrangements are:Simplicity in the designMaintenance of different elements without interruption in the power supplyFuture expansion feasibilityEconomical in cost of installation and operationDifferent busbar arrangements:Some of the switching schemes are busbar arrangements employed in the substations are listed below:Single Bus-bar arrangementDouble Main Bus-bar schemeMain and Transfer bus-bar schemeOne and half breaker schemeRing Main arrangement schemeSingle Bus-bar scheme:This is the simplest busbar scheme available which consists of single set of busbars connected to the generators, transformers and load feeders. All the feeders are connected by circuit breaker and set of isolators. This arrangement helps to remove the connecting elements (Generators, transformers, etc ) for maintenance by opening the circuit breaker contacts and further opening the isolators.Advantages:This busbar arrangement enjoys less cost of installationLess maintenancesimple operationDisadvantages:Fault on the busbar all the feeders connected to the busbars should be disconnectedwhen Busbar is under maintenance total supply and all feeders should be disconnectedLeast flexibility and reliabilitySee all 5 photosSingle busbar SchemeDouble Main Busbar Scheme:Normally in double main busbar scheme each circuit is connected to both the buses. In some cases half of the circuits can be connected and operated on each bus, in these cases bus or circuit breaker failure would cause loss to half of the circuits. In double main busbar arrangement one or two breakers can be provided for each circuit. Double main busbar and double breaker scheme provides high reliability in the case of fault or outage of one of the breaker.Advantages:Any circuit can be taken out of circuit for maintenanceFlexibility in connecting the feeder circuit to either of the busbarsDisadvantages:Most expensiveLoose circuits connected to busbar when fault occurs on the busbarDouble Busbar Single Breaker SchemeMain and Transfer Busbar SchemeMain and Transfer busbar scheme is similiar to single busbar arrangement with additional transfer bus connected. Tie circuit breaker is provided to tie both the main and transfer bus. During normal operation all the circuits are connected to the main bus. When circuit breaker connected to the circuit (transmission line) is required to trip for maintenance, tie circuit breaker connecting the main and transfer bus is closed. The relay protection for the circuits connected to the transfer bus is taken care by the tie circuit breaker.Advantages:Low initial costAny breaker can be taken of circuit for maintenanceDisadvantages:Requires one extra breaker for bus tieSwitching is somewhat complicated when breaker is under maintenanceMain and Transfer Busbar SchemeOne and Half breaker Busbar scheme:In One and half breaker scheme, two circuits are connected between the three circuit breakers. Hence One and Half breaker name was coined for this type of arrangement. Under normal operating conditions all the breakers are closed and both the busbars are energized. Any Circuit fault will trip two circuit breakers and no other circuit will be affected in this arrangement. When a busbar fault occur only breakers adjacent to busbars trips and no circuit will loose power. Two busbars can also be taken out of service with out affecting the power flow if the power source circuit ( alternator circuit) and receiving circuit (transmission line) available in the same bay.Advantages:Most flexible operation possibleHigh reliabilityBus failure will not remove any circuit from serviceDisadvantages:High costRelaying is somewhat complicated since the middle breaker must responsible for both the circuits on either direction and should operateone and Half Breaker SchemeRing busbar schemeIn this ring main busbar scheme arrangement, breakers are connected in ring and circuits are connected between the breakers. There will be same number of circuits as the number of breakers in the arrangement. During normal operation all the breakers are closed. During circuit fault two breakers connecting the circuit trips. During breaker maintenance the ring is broken but all the lines remain in service.Advantages:Low costFlexible operation for breaker maintenanceAny breaker can be taken out of service without interrupting loadPower can be fed from both the directionDisadvantages:Fault occur during maintenance will break the ringRelaying is complexBreaker failure during fault will trip one additional circuitRing Main Busbar Scheme
In 2001 non-airbreathing rockets have one of two types of main propulsion systems What are tyey?
LIQUID PROPELLENTS OR SOLID PROPELLANTS
