Sep 26, 2020
Application of SSR soft starter in fire water supply
With the rapid development of modern fire protection, the application of microcomputer soft start technology in the fire water supply system is crucial. It can completely solve many problems of fire pump power frequency (star angle or auto-decompression) start.
1. Existing problems in the control and starting mode of the water pump of the fire water supply system.
In the fire water supply system, whether the fire pump and sprinkler pump can ensure normal operation at any time is of vital importance. The fire pumps and spray pumps established in the past have serious technical problems in the electric control system, using power frequency (star angle or auto-coupling step-down starting method) to start. This control method has poor reliability and instability, and will cause electrical shocks and mechanical shocks during each startup and shutdown. As a result, a series of technical problems have occurred: For example, the high starting current of the larger water pump motor under load may easily cause the control system to crash, trip, or power failure. At the same time, it causes water hammer to the water system pipe network, and easily damages the valves, check valves, and water pump couplings, which seriously affect the service life of the equipment. An immeasurable hidden danger has been buried in the fire protection project, which is unsafe and unreliable. In order to solve this problem, a special person had to be on duty to look after the valve. The valve was regularly opened and the pump was energized to prevent the pump from being left idle for a long time. If there is a fire, professional personnel must also work in accordance with the pre-established operating procedures: first close the valve, then turn on the power to start the motor, and then slowly open the valve when it runs normally. (At this time, the valve is working because the pump is running. If the pressure is too high, the valve can be opened with greater force, and it is easy to damage). It will take at least 10 minutes or even more than half an hour from the information of the fire occurrence to the normal operation of the equipment. Difficulty in starting, resulting in delays, loss of the most advantageous time to extinguish the fire, and a large fire from a small fire. The consequences are unimaginable. The application of star angle or auto-coupling step-down starting method is allowed to be adopted in the fire protection design code and conforms to the design. Canonical. However, in combination with my country's national conditions, in practical applications, the drawbacks of technical problems, coupled with unclear management responsibilities, have caused the fire protection facilities to be useless. Can not ensure the safe and normal operation of fire fighting equipment. Especially in enterprises and institutions with full power consumption, such problems are more likely to be exposed. There are often some fire-fighting facilities. When new construction projects are inspected and accepted, they generally pass the acceptance and reach the standard. However, when it is put into normal operation, the fire pump and sprinkler pump cannot start normally. This is because the transformer is working at full load according to the design. If the large motor suddenly starts at this moment, the current is too high and it is easy to cause a crash Or the occurrence of problems such as power failure. If it continues, it will lose the ability to manually start and automatically start the fire extinguishing, which will inevitably lead to the following major problems in the power frequency (star angle and auto-coupling step-down) startup mode described above:
(1) Large electrical impact force; (2) Large mechanical impact force; (3) Larger water pump motors need manual start-up, so it is difficult to realize automatic inspection; (4) Larger motors start with load and it is difficult to close the valve without closing the valve Automatic and manual start-up makes the start-up time too long and delays the time to put out the fire.
2. Features and performance of using SAFESAVE-SSR series motor soft starter to control fire pump
The SAFESAVE-SSR series motor soft starter is adopted, and the larger fire water pump does not need to close the valve to start. The SAFESAVE-SSR series motor soft starter can be started directly. The SAFESAVE-SSR series motor soft starter completely solves the problem in the fire protection system. Due to the heavy load of the water pump motor and the excessively high starting current, problems such as crashes or power failures are caused. This technology of SAFESAVE-SSR series motor soft starter mainly lies in the microcomputer controlling the voltage conduction angle, so that the starting current and voltage are under the digital control of the microcomputer, with ramp voltage, current limit, ramp voltage + current limit and other settings. In this way, the motor input voltage and current are within the designed rated range, reducing and reducing the inrush current, step by step (gradual increase or decrease working mode), to achieve smooth soft start and soft stop effects.
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