BACKGROUND ART Generally, lightings are mounted to a hotel lobby, or a ceiling of a factory or gymnasium, or on a street in high places. These lightings in high places require periodical or frequent exchange of light bulbs due to limited life or breakdown of the light bulbs, and the lightings should also be cleaned periodically if they are mounted in a place such as a hotel lobby that needs cleanness. Since such lightings are mounted in high places, a crane or an aerial ladder truck is used for cleaning or exchanging a light bulb.

However, such cleaning or exchanging work in a high place is very inconvenient rather than that on the ground, so a worker is exposed to dangers such as an electric shock and a fall. In addition, the supplementary equipment required for the work causes additional costs for repair and maintenance. Thus, in order to solve such problems, there has been proposed a highly-mounted lighting lift device that basically

includes a main body fixed near the ceiling, a lift unit combined in contact with a lower portion of the main body and provided with a lamp unit fixed at a lower portion thereof, a wire having one end fixed to an upper portion of the lift unit and the other end fixed to a drum mounted at a certain portion of the main body, and a driving source for driving the drum to take up the wire so that the lift unit is moved vertically.

The highly-mounted lighting lift device configured as mentioned above is operated so that the driving source is operated with the use of a wired button or a wireless remote controller, and the drum receiving the power of the driving source unties the wire to make the lift unit be descended near to the ground. Thus, the lift device ensures safety and convenience to a worker who exchanges, cleans or repairs a light bulb.

A single-phase induction motor is generally used as the driving source. The single-phase induction motor is widely used as a driving motor of lightings and other various electronic devices in house, office, factory or farmland because it has simple and firm structure and a single-phase power is easily obtained as its driving source.

The induction motor mounted in the conventional highly-mounted lighting lift device is shown in FIG. 1. Referring to FIG. 1, a starting condenser 40 is connected in parallel between a main winding line 11 and a sub-winding line 12 that transfer power to a main winding and a sub-winding of a single-phase induction motor 10 respectively.

Thus, a power source 30 supplies power to the main winding line 11 and the sub-winding line 12 of the single-phase induction motor 10 by control of a micro controller 20 so as to drive the single-phase induction motor 10.

However, this single-phase induction motor disadvantageously has a very weak

initial starting power rather than other kinds of induction motors, though there is no serious problem after a rotor is accelerated to obtain an increased force since the initial starting.

DISCLOSURE OF INVENTION The present invention is designed to solve the problems of the prior art, and therefore an object of the invention is to provide a starting power improved apparatus of a single-phase induction motor, which is capable of improving an initial starting power of a single-phase induction motor for a lift system of a lighting in a high place.

In order to accomplish the above object, the present invention provides a starting power improved apparatus of a single-phase induction motor for a lift system of a lighting in a high place, which has a main starting condenser for generating a starting power and is switched by control of a micro controller, and which includes an auxiliary starting condenser connected in parallel to the main starting condenser; and an operation switch connected in series to the auxiliary starting condenser to switch the auxiliary starting condenser by control of the micro controller.

Preferably, the auxiliary starting condenser is temporally turned on and then turned off when the single-phase induction motor is started.

BRIEF DESCRIPTION OF THE DRAWINGS These and other features, aspects, and advantages of preferred embodiments of the present invention will be more fully described in the following detailed description, taken accompanying drawings. In the drawings:

FIG. 1 is a circuit diagram showing a single-phase induction motor used in a conventional highly-mounted lighting lift device; FIG. 2 is a circuit diagram showing a starting power improved apparatus of a single-phase induction motor according to a preferred embodiment of the present invention; and FIG. 3 is a circuit diagram showing that the starting power improved apparatus of a single-phase induction motor of FIG. 2 is applied.

BEST MODES FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the invention.

First, on the drawings, the same components are indicated by the same reference numeral though they are depicted on different drawings.

FIG. 2 is a circuit diagram showing a starting power improved apparatus of a single-phase induction motor according to the preferred embodiment of the present invention.

As shown in FIG. 2, the starting power improved apparatus 100 of this embodiment includes a main starting condenser 40, an auxiliary starting condenser 120 connected in parallel to the main starting condenser 40, and an operation switch 110 connected in series to the auxiliary starting condenser 120 to switch the auxiliary starting condenser 120.

Here, the operation switch 110 is controlled by a micro controller 20 that is in

charge of switching a starting circuit of the single-mode induction motor. When the apparatus 100 is started, the operation switch 110 preferably keeps a turning-on state for a short time within one second.

FIG. 3 is a circuit diagram showing that the starting power improved apparatus 100 of a single-phase induction motor shown in FIG. 2 is applied. Referring to FIG. 3, it might be understood that the auxiliary starting condenser 120 and the operation switch 110 are connected in parallel to the main starting condenser 40 that is connected in parallel between a main winding line 11 and a sub-winding line 12.

Seeing its operation, if a main power switch is turned on by control of the micro controller 20, AC voltage is applied from a power source 30 and the AC voltage is connected to the main winding line 11 and the sub-winding line 12. At this time, a relay 50 is operated to instantly turn on the operation switch 110.

And then, while the operation switch 110 is turned on, the auxiliary starting condenser 120 is connected in parallel to the main starting condenser 40, thereby increasing condenser capacity. Thus, the starting power is increased rather than the conventional case in which only the main starting condenser 40 generates a starting power. In addition, the operation switch 110 is turned off so as to interrupt operation of the auxiliary starting condenser 120 after the apparatus is started, so overheat of the induction motor is prevented.

The present invention has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will

become apparent to those skilled in the art from this detailed description.

INDUSTRIAL APPLICABILITY As described above, the starting power improved apparatus of the present invention may improve a starting power of the single-phase induction motor that is used as a power source of a lift system of a lighting in a high place, and it ultimately enhances the overall performance of the lift system of a lighting in a high place in which the single-phase induction motor is used.