Patent Application
20080159876
1. Field of the Invention
The present invention relates to a protective device for a controlling system of a sewage pump, and more particularly to a protective device that controls pump operation and has a protective circuit protecting a start capacitor in the controlling system to avoid the start capacitor from burnout when an overload is occurred by actuating power source (ON status) or when a transient voltage is occurred by malfunction of a controlling circuit.
2. Description of Related Art
A conventional sewage pump system in accordance with the prior art has an operational controlling circuit system for controlling the operation of a sewage pump. The operational controlling circuit system has a start capacitor connected with a run capacitor in parallel connection and with a switch in series connection and further connected with an actuating coil and an operating coil to perform a combined circuit. In the operational controlling circuit system, the actuating coil and the operating coil drive the sewage pump to function when the electrical power is supplied. Because the switch is the essential element to control the sewage pump to work or to stop, its contact is always changed between a normal closed (N.C.) status and a normal open (N.O.) status. Moreover, its contact has carbon-deposition or oxidation incurred by electric sparkles of large current. Therefore, the contact can not successfully disengage and is kept at the normal closed (N.C.) status that makes the start capacitor to electrically connect the power source. When the start capacitor is kept to be charged, it will burnout sooner or later.
According to above description, the conventional sewage pump system still has some drawbacks in use.
A main objective of the present invention is to provide a protective device for a controlling system of a sewage pump, wherein the protective device protects a start capacitor from keeping discharge and burnout when a switch is abnormally suspended at a normal closed (N.C.) status.
To achieve the foregoing objective, the protective device for a controlling system of a sewage pump with a start capacitor and a run capacitor, the protective device comprising a protective circuit composed of a centrifugal switch adapted to mount on an output shaft of the sewage pump and providing a protective efficiency by cutting power to avoid the start capacitor in the sewage pump from burnout.
By having the protective circuit, the start capacitor is protected from burnout to have extended lifespan.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.
A protective device for a controlling system of a sewage pump in accordance with the present invention has a protective circuit to protect a start capacitor and to avoid the start capacitor from burnout when an overload is occurred by actuating power source (ON status) or when a transient voltage is occurred by malfunction of a controlling circuit. Therefore, the start capacitor is certainly protected and significantly improved in lifespan.
The protective device for a controlling system of a sewage pump is applied to an operation-controlling circuit system 2 to drive a sewage pump 1 as shown in
According to above description, the protective device for a controlling system of a sewage pump has the following advantage that:
the centrifugal switch in the protective device is a mechanical centrifugal switch and changes it contact from the normal closed (N.C.) status to the normal open (N.O.) status by the centrifugal force from rotation of the central shaft 4. Thereby, the start capacitor 21 is electrically isolated from the power source because of the broken circuit. Then, the start capacitor 21 stops the discharging movement and the functioning status of charging or discharging to protect itself from burnout during long-term operation.
Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present invention of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts any be resorted to without departing from the spirit and scope of the invention.
