ELECTRICAL EQUIPMENT for MODERN HOTELS
BY OTTO E. GOLDSCHMIDT*
T
HE rapid progress in the development of electrical equipment is naturally taken up by our modern hotels and now requires a most careful study to insure the equipment meeting the special demands of the hotel service. The electric wiring equipment for light and power service pertaining to our modern fireproof hotels is therefore of particular interest.
The current supply for a modern hotel is one of the first problems that should be given consideration. There are generally two sources, that is, either the current is obtained from some power company and the current is paid for on a meter rate or a generating- plant is installed in the building itself for producing the electric power. The advantages of either one of these systems are entirely dependent upon local conditions and vary with almost every hotel operation. The cost of current supplied by the local pow
er company is, of course, the basic factor. The size of the hotel is also a very important factor. The dependability of outside supply, the cost of coal and labor, the possibility of using exhaust steam for heating during the winter months and for producing hot water throughout the year are all important factors which enter into the consideration of this problem and very careful study must be given each to arrive at a correct final analysis. As a general proposition there is no building which lends itself so favorably to an electric generating plant as a hotel, principally owing to the fact that all or at least a considerable amount of the exhaust steam can be utilized throughout the year for which, without a generating plant, live steam would have to be furnished. During such periods when all the exhaust steam is utilized the electric power is really a by-product. In some localities a very satisfactory arrangement has been worked out where the hotel was able to purchase its electric power during the summer months and to generate its own power during the winter months when all exhaust steam can be utilized for heating purposes. The necessity of a break-down service, where a power plant is installed, is now not considered essential as with reasonable care by the operating
force there should be no occasion for a shut-down of any kind in the generating plant. Where current is supplied from hydro-electric plants and the power is transmitted by overhead lines an occasional shutting off is unavoidable especially during the summer months while electrical storms prevail as lightning frequently strikes the wire and poles and causes power to be shut off for periods from a few minutes to several hours.
Where the service is taken from some outside source the system of electric light and power wiring as now usually installed consists of the
necessary service mains from the street which are brought in to a main distribution switchboard. When the current supply is 220 volts, 3 wire, direct current, is carried directly to this main switchboard and distributed from the same by feeders to the various panelboards for light and power distribution.
Where the current supply is alternating current, the supply may be brought in in two different ways. If the power company furnishes its own transformers mounted either on a pole or in a street vault the supply is carried in from these transformers at low tension through service mains which are connected into the main distribution board as in the case of direct current supply. If the current supply is brought into the building as high tension current, above 500 volts, it must be transformed in the building itself to low tension current. It is then necessary to provide in the basement of the building or some adjoining separate building a transformer vault in which the various transformers for light and power are placed and in which all the high tension connections are made. The low tension service mains are carried from these transformers to the main switchboard as above described. The selection as to whether the current is to be brought in as high tension or low tension is generally dependent upon the difference in rate at which the local company supplies its power. The high tension current can usually be purchased more cheaply than the low tension but the added first cost of transformers, connections, etc., must be given consideration. The transformer vault must be of fire
proof construction, provided with outside ventila-* Consulting Engineer, New York City.
Main Switchboard, Hotel Statler, Buffalo, N. Y.
BY OTTO E. GOLDSCHMIDT*
T
HE rapid progress in the development of electrical equipment is naturally taken up by our modern hotels and now requires a most careful study to insure the equipment meeting the special demands of the hotel service. The electric wiring equipment for light and power service pertaining to our modern fireproof hotels is therefore of particular interest.
The current supply for a modern hotel is one of the first problems that should be given consideration. There are generally two sources, that is, either the current is obtained from some power company and the current is paid for on a meter rate or a generating- plant is installed in the building itself for producing the electric power. The advantages of either one of these systems are entirely dependent upon local conditions and vary with almost every hotel operation. The cost of current supplied by the local pow
er company is, of course, the basic factor. The size of the hotel is also a very important factor. The dependability of outside supply, the cost of coal and labor, the possibility of using exhaust steam for heating during the winter months and for producing hot water throughout the year are all important factors which enter into the consideration of this problem and very careful study must be given each to arrive at a correct final analysis. As a general proposition there is no building which lends itself so favorably to an electric generating plant as a hotel, principally owing to the fact that all or at least a considerable amount of the exhaust steam can be utilized throughout the year for which, without a generating plant, live steam would have to be furnished. During such periods when all the exhaust steam is utilized the electric power is really a by-product. In some localities a very satisfactory arrangement has been worked out where the hotel was able to purchase its electric power during the summer months and to generate its own power during the winter months when all exhaust steam can be utilized for heating purposes. The necessity of a break-down service, where a power plant is installed, is now not considered essential as with reasonable care by the operating
force there should be no occasion for a shut-down of any kind in the generating plant. Where current is supplied from hydro-electric plants and the power is transmitted by overhead lines an occasional shutting off is unavoidable especially during the summer months while electrical storms prevail as lightning frequently strikes the wire and poles and causes power to be shut off for periods from a few minutes to several hours.
Where the service is taken from some outside source the system of electric light and power wiring as now usually installed consists of the
necessary service mains from the street which are brought in to a main distribution switchboard. When the current supply is 220 volts, 3 wire, direct current, is carried directly to this main switchboard and distributed from the same by feeders to the various panelboards for light and power distribution.
Where the current supply is alternating current, the supply may be brought in in two different ways. If the power company furnishes its own transformers mounted either on a pole or in a street vault the supply is carried in from these transformers at low tension through service mains which are connected into the main distribution board as in the case of direct current supply. If the current supply is brought into the building as high tension current, above 500 volts, it must be transformed in the building itself to low tension current. It is then necessary to provide in the basement of the building or some adjoining separate building a transformer vault in which the various transformers for light and power are placed and in which all the high tension connections are made. The low tension service mains are carried from these transformers to the main switchboard as above described. The selection as to whether the current is to be brought in as high tension or low tension is generally dependent upon the difference in rate at which the local company supplies its power. The high tension current can usually be purchased more cheaply than the low tension but the added first cost of transformers, connections, etc., must be given consideration. The transformer vault must be of fire
proof construction, provided with outside ventila-* Consulting Engineer, New York City.
Main Switchboard, Hotel Statler, Buffalo, N. Y.