Reserve power supply

High power primary zinc-air cells are also developed with nominal current 20A -v 40A and capacity in the range 100 Ah -v 320 Ah. Typical application of these powerful zinc-air cells is as easy activated reserve power supply. These cells also can be successfully used for traction. 

Protection against loss of data due to power failure. The microprocessor and digital clock are provided with reserve power supplies, which ensures that, if the normal mains supply should fail, the timing continues uninterrupted and there is no loss of data from the RAM. After restoration of the normal supply following a power failure, the time, date and stored data are recorded by the output equipment and normal automatic operation is resumed. Recharging of the reserve power-pack also takes place when the operation from the mains supply is restored. No reserve supply is required by the PROM, whose memory contents are unaffected by disturbances to the mains. 

Biggar, A. M., R. C. Proestel, and W. H. Steuemagel A 48-Hour Reserve Power Supply for a Scat-terable Mine, Proc. 26th Annual Power Sources Symp., Electrochemical Society, Pennington, NJ, pp. 126-129, 1974. 

The state of full ability Sp is a state in which the properly functioning both power sources (both primary and reserve). State of the impendency over safety S bx is a state in which the basic power supply is unsuitable. State of the impendency over safety is a state in which the reserve power supply is unsuitable. State of unreliability of safety Sb is a state in which the two power sources are unsuitable. 

If the system is in state of full ability Sp and there occur the damage of the reserve power supply that takes the system to the state the impendency over safety with intensity system... 

A field of application offering a vast potential market is the use of lead-acid batteries as energy storage systems by electrical utility companies (for load levelling and reserve power supply) and their customers (for... 

The DOE N-Reactor is one of the plutonium production reactors located on the Hanford Reservation near Richland, Washington. It is graphite moderated, pressurized water reactors that in addition to production of special nuclear materials also provided steam to turbine generators owned by the Washington Public Power Supply System for electric power production. It began op ition in 1 is put into standby status in 1988 and closed because of similarities to Chernobyl. 

In 1990, the National Academy of Science completed an energy study that concluded that commercial fusion power may be required by the year 2050. By that time 40 percent of the oil reserves will have been consumed, and current natural gas reserves can supply only about half of the projected needs. The discovery of additional deposits and improved production might meet the need for natural gas, but at a higher price. 

The JL900 type samplers are equipped with an alarm system with two GM-tubes above the filter. The readings from the GM-tubes are updated in 1 min intervals and an alarm level of 0.5 pSv/h for a 15 min average reading is in use. For preparedness purposes there are in addition three samplers of type JL150 in reserve. Two of them are located in Helsinki and one is located in Rovaniemi. If needed, they can readily be brought into use and operated anywhere in Finland with the standard 230V (1 kW) power supply. One of the reserve samplers is equipped with a timer. 

Several terms for pressure measuring devices are used interchangeably including transmitters, transducers, gauges, sensors, and manometers. More precisely, a gauge is a self-contained device that converts a force from the process to a mechanical motion of needle or other type of pointer. A manometer is a term reserved for an instrument that measures the hydrostatic head of a liquid and generally operates near atmospheric pressure. A transducer or transmitter combines the sensor with a power supply and a converter— generally mechanical-to-electrical or mechanical-to-pneumatic. The sensor... 

The outer control rod drives (CRDs) shall be designed to permit the Safety Protection Subsystem to interrupt the power supply to the drives when reactor trip levels are reached, causing the control rods to drop by gravity into the core. The inner control rod drives shall operate in a similar manner but are tripped from the Investment Protection Subsystem. This trip command shall override all other commands. The reserve shutdown material shall be stored in hoppers above the core and released to fall into the core upon receipt of a signal from the Safety Protection Subsystem. 

Common practice in the offshore industry is to have available power supply capacity necessary for the installations and some amount for reserve or backup in the form of local generators. The offshore industry is using the same concept also for supply from land. It is then often experienced that the land to offshore connection affects the power system such that required amount of power may not be available during periods of the year. Furthermore, the quahty of service is different from having dedicated generators and... 

The term concentrator or intelligent concentrator (or smart hub) is often reserved for a device characterized by its flexibility and expandabihty. A concentrator starts with a fairly empty, boxlike device often called a chassis. This chassis contains one or more power supplies and a builtin network backbone. This backbone might be ethernet, token ring, FDDI, or some combination of these. Into this backplane, individual cards or modules are inserted. 

To limit maximum temperature of the reactor module in the first period of aftercooling, forced circulation of the primary sodium is employed, using the sodium circulation pumps. In this, the power for the pumps is supplied either from the main generator or from small-power generators connected to the shafts of the turbo-machines, or from reserve power sources - on the total, there is a five-fold redundancy of power supply for the main circulating pumps. 

A problem of alternatives Suppose that one of the cells will be out of commission due to maintenance for 10% of running time. Should we install a standby cell or raise the current density for the remaining 19 cells The choice is determined by relative cost. To raise the current density of operation, reserve capacity may be required in the power supply and the cooling unit. The cost of the alternatives is examined in Table 6.15 additional investment for a standby unit is not justified in view of the high payback time of alternative 1. 

Requirements for the availability of the electrical power sources should be stated for all operational states. These include off-site sources on-site generators (diesels and gas turbines, including associated fuel reserves) batteries and associated control protective, distribution and switching devices. The operability requirements should be such that sufficient power will be available to supply all safety related equipment necessary for safe shutdown of the plant, and for the mitigation and control of accident conditions. The operabihty requirements should determine the necessary power, redundancy of supply lines, maximum permissible time delays and necessary duration of the emergency power supply. Equivalent requirements should be stated for other power sources (for example, the pneumatic power system). Particular care should be taken to ensure that electrical supplies remain adequate in shutdown operations, when many systems and components will be out of service for maintenance. 

This group of characteristics generally specifies power supply systems that are available at the unit in case of a loss of unit auxiliary power caused by a turbine or main generator trip. At some NPPs, dedicated neighbouring power plant units are used as an alternative source of auxiliary power. Most NPPs also have dedicated off-site transmission lines to supply on-site reserve transformers as alternative sources of unit auxiliary power. Units usually have on-site emergency power sources, such as diesel generators, gas turbines and accumulator batteries, in case all off-site power sources are lost. 

During maintenance on the main step-up transformers, power comes from the high-voltage substation by way of the two reserve auxiliary transformers (station transformers, in UK parlance). Each reserve auxiliary transformer can be used in place of a unit auxiliary transformer that is, its output rating is the same. Bus transfer to the maintenance power supply is manual or automatic, through a fast bus transfer scheme. 

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