Motor starters

If maintenance is performed, there are two principal maintenance strategies preventive and breakdown maintenance. These are not mutually exclusive, and may be combined even in the same piece of equipment. Take for example a private motor car. The owner performs a mixture of preventive maintenance (by adding lubricating oil, topping up the battery fluid, hydraulic fluid and coolant) with breakdown maintenance (e.g. only replacing the starter motor when it fails, rather than at regular intervals). 

Electrical. The plant electrical system is sometimes more important than the steam system. The electrical system consists of the utihty company s entry substation, any ia-plant generating equipment, primary distribution feeders, secondary substations and transformers, final distribution cables, and various items of switch-gear, protective relays, motor starters, motors, lighting control panels, and capacitors to adjust power factor. 

Transportation end uses are expected to become a significant outlet. Products under development include an engine valve cover, as are various housings such as those for od pumps, water pumps, starter motors, and certain transmission parts. These end uses employ PPS because it resists high temperatures and is also chemically resistant. Fuel system parts can employ the excellent chemical resistance of PPS, replacing nylon, if alcohol-based fuels are adopted to reduce emissions. 

The lead storage battery provides electrical power in automobiles. It is well suited for this use because it supplies the large current needed to drive starter motors and headlights and can be recharged easily. Figure 19-20 shows the lead storage cell in a schematic view. The half-reactions are the subject of Example ... 

C19-0079. If it takes 15 seconds to start your car engine and the battery provides 5.9 A of current to the starter motor, what masses of Pb and Pb02 are used in each batteiy cell ... 

The detailed-t eoff method can rarely if ever be used. When detailed drawings are available, costs may be estimated by pricing materials and components from suppliers catalogs or, for special items, from quotations. Handbooks are available which give typical values of the labor-hours required to perform units of installation work, such as installation of switches, starters, motors, conduit wiring, and push buttons of various sizes, for both hazardous and nonhaz-ardous areas. Labor rates can be obtained from various government statistical sources or elsewhere. For the United States the National Electrical Contractors Association publishes an excellent manual of electrical costs. From the complete plans and specifications, the estimator can take off materials, estimate the labor cost, apply appropriate factors for labor efficiency, productivity, and local conditions, and achieve good results. 

However, if the battery is discharged to run the starter motor and then recharged by using a finite current flow, as is actually the case, more work will always be required to recharge the battery than the battery produces as... 

A battery can do work by sending current to a starter motor. The battery can then be recharged by forcing current through it. If the current flow in both processes is infinitesimally small, wn [ = w21. This is a reversible process. But if the current flow is finite, as it would be in any real case,... 

Steam carriages were used as fire engines in several cities after the Civil War was over. Steam cars competed with internal combustion vehicles in the first decade of the 20th century. The Stanley, Locomobile, and White steam cars had many fans. The cars were admired for their silent option, range and there was no need of a crank handle for starting. Starter motors would appear much later. This edge was shared by electric cars and was a real consideration since careless cranking could injure your arm. 

The starter motor was a high-speed d.c. motor with a speed reduction ratio of about 50 1 to the crankshaft of the combustion engine, and this is the method still used today. Given that the start routine is very short, both the battery and starter motor have, over the years, undergone a complete optimization to obtain the best possible torque for the lowest possible manufacturing costs. As a result, no other system has yet gained a foothold in series-manufactured vehicles. 

Occasionally process gas can be nsed instead of air to drive the air/gas starter motor. This eliminates the need for receivers and compressors. However, there shonld always be a reliable source of gas available. The exhaust gas from the starter motor should be safely discharged e.g. into a ventilating pipeline. 

Some of the vital and essential loads are required when the plant is to be started up, and there is no normal power available. In this situation the starting up of the plant is called black starting . The emergency generator must be started from a source of power, which is usually a high capacity storage battery and a DC starter motor, or a fully charged air receiver and a pnemnatic starter motor. 

Power wheelchairs began in the 1940s as standard cross-brace folding manual wheelchairs adapted with automobile starter motors and an automobile battery. The cross-braced wheelchair remained the standard for a number of years. When the rigid power wheelchair frame was developed, space became available under the seat for electronic controls, respirators, communication systems, and reclining devices. By the mid-1970s, wheelchairs had evolved to the point where people had acquired a significant level of mobility. 

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