THE ELECTRIC ELEVATOR. The electric elevator-or as it is described in England, the Electric Lift-is a combination of the regular elevator with the electric motor; i. e., the power applied to raise and lower, is the electric current, as against water pressure or steam pressure. The adaptability of electricity to all service where power is required was never so apparent as in its application to passenger elevators; the success of the electric hoist seems destined to develop a field the extent of which has not yet been calculated. The essential features of the electric elevator are: (1) high speed, (2) absolute safety, (3) completely under control of operator, (4) applicable to the current to be supplied by the lighting mains, (5) low cost of operation and maintenance. In the hydraulic pumping system as well as in the hydraulic street pressure system, it is noteworthy that just as much water is required to carry up the empty car as to carry up a full load, and If a steam pump is used it is necessary to keep the fire burning under the boiler and to keep the steam up all the time, although the pump in most cases runs only a small portion of the time, so that the consumption of coal is many times larger in proportion to the power used than in ordinary steam engines of equal power, but— THE ELECTRIC ELEVATOR. If electricity is used in connection with a proper motor, the consumption of current stops when the work stops, which insures great economy of operation whether the current supply is obtained from a central station or from owner's dynamos. The advantages of the device as summarized are as follows: Advantages of the Electric Elevator. I. 2. As compared with hydraulic elevators. No frozen or burst water pipes. No flooded cellars. No piston to pack and grease. No leaking valves or cylinders. No air to cause runaways. No excessive weight to bring car down. No heavy or unsightly tanks on roof or pressure tanks occupying valuable space. No creeping of car away from landing, if left for a few minutes. No water pipes to fill up or corrode, thereby reducing power and speed. As compared with steam elevators. No odors or heat. No ashes, dust, or dirt. No boiler insurance. No costly space occupied. No vibration of building or disagreeable noises. THE ELECTRIC ELEVATOR. 3. General advantages. Prompt and easy start. Smooth running. Quick and smooth stop, regardless of load, speed, or skill Requires minimum attention. Speed practically uniform under all loads. Large margin of power. Minimum operating expense. Extreme simplicity, few moving and wearing parts. Most approved safety devices. Points" relating to the Electric Elevator: The satisfactory working of an electric elevator depends largely upon the devices by which it is started, stopped, and reversed; an automatic switch and rheostat (or regulator) should be provided, by which these changes can always be made properly without strain on the apparatus, with perfect smoothness and without the exercise of skill on the part of the operator. Pulling the rope downwards as far as possible causes the car to ascend. A slight pull in the opposite direction opens the switch, allows the brake to apply and the car comes to a stop. Pulling the rope upwards as far as possible causes the car to descend. The same effect is produced by the turning of a hand wheel-forwards or backwards. Any apparatus will wear in time, and therefore elevators should be equipped with the most reliable and improved forms of safety appliances. |