2019年9月19日星期四

Soft starter in the control of fire pumps, spray pump applications

Abstract: The microcomputer-controlled motor soft starter to solve the technical problems related to the start-up of the power frequency (star angle and autocoupler) involves the fire water supply technology.

Key words: soft starter, electric shock, mechanical impact, PLC programmable, mechatronics , power factor

With the rapid development of our country's modern fire-fighting cause, the soft-start technology of microcomputer is very important in the application of fire-fighting water supply system. It can completely solve many problems of start-up of fire pump frequency (star angle or autocoupler).

First, the fire pump water supply system control and start-up problems.

1, in the fire water system, fire pump, spray pump can guarantee normal operation is crucial. In the past set fire pump, spray pump in the electronic control system, the use of power frequency (star angle or autoclaved start-up mode) there is a more serious technical problems. This control method, poor reliability, instability, each start and stop the process will cause the impact of electricity and mechanical shocks. As a result, a series of technical problems occur. For example, a large pump motor with a high load starting current may easily cause a crash of the control system, or a switch-off or power-off. Water pipe network caused by water hammer at the same time, the valve , check valve, and pump coupling and so easy to cause damage, seriously affecting the service life of its equipment. Buried in the fire engineering immeasurable hidden dangers, that is unsafe, but not reliable.

In order to solve this problem, we have to arrange special duty on duty to take care of the valve. Operators periodically open the valve, energize and operate the pump to prevent the pump from rusting for a long time. If there is a fire , you also need to set up a professional work procedures according to the pre-defined operation: First of all, to close the valve, and then send electricity to start the motor until the operation is normal and then slowly open the valve (when the valve is running due to the pump, work The pressure is too high, open the valve hard, it is easy to damage), from the fire information, until the equipment is operating normally, at least 10 minutes or so, even more than half an hour, if due to human error or equipment Start with difficulties, resulting in delays, loss of the most favorable opportunity to extinguish fire, caused by a small fire and a fire, the consequences are unimaginable.

2, the application of star angle or step-down self-starting mode in the fire design specifications are allowed to adopt, is in line with design specifications. However, in light of China's national conditions, in practical applications, the drawbacks of technical problems and the unclear management responsibilities have caused firefighting facilities to exist in name only. Can not ensure the safety of fire equipment to work properly. Especially in the electricity-consuming enterprises and institutions more easily exposed such problems.

Often, some fire-fighting facilities can pass the inspection and acceptance when the new construction inspection and acceptance is completed. However, when it is put into normal operation, the fire pump and the spray pump can not start normally. This is because the transformer is already working at full capacity according to the design. If at this moment a large motor starts suddenly and the current is too high, it will easily cause a crash Or power outages and other issues. If it goes on, it will lose the ability to manually start and automatically start fire extinguishing, which will inevitably lead to serious consequences.

In summary, the power frequency (star angle and auto-buck) start-up mode there are several main problems:

(1) large electric impact force; (2) large mechanical impact force; (3) large pump motor requires manual start-up, so it is difficult to realize automatic inspection; (4) Automatic, manual start, so start-up time is too long, delay the fire extinguishing time.

Second, with computer soft starter fire pump control the characteristics and performance

Using DWQ series motor soft starter, the larger fire pump does not need to close the valve start, you can start directly in the fire fighting system, completely solve the pump motor load, starting current is too high and cause crashes or power failure and other issues . This technology is mainly controlled by the computer voltage conduction angle, the starting current, voltage digital control under the computer, with a ramp voltage, current limit. Ramp voltage and current can be set a variety of start-up mode, the motor input voltage and current within the design rated range, reduce and reduce the impact of current, step by step (gradually increase or decrease the work), to achieve a smooth soft-start and soft stop effect . This technology can be achieved electromechanical integration, automation , unmanned operation, safe and reliable. The product on August 15, 1998 through the national fixed fire extinguishing systems and fire-resistant components Quality Supervision and Inspection Center for type testing, determine the qualified products. And on May 5, 1999 by the Liaoning Provincial Fire Department formally approved the production and sale . DXGS microcomputer automatic fire control water supply equipment, the main choice DWQ series motor soft starter, PLC programmable logic controller for the main control unit. The formation of control of non-contact, automatically set the cycle inspection; automatic control of electric valve to ensure the return of open and close flexible; automatic recording of operating hours and operating conditions; in case of fire alarm signal with sound and light alarm; case of equipment failure with sound and light Alarm; with long-distance control, manual, automatic timing switch, and additional functions such as running.

DWQ series motor soft starter with phase sequence, phase loss, over current, over voltage, under voltage, overheat protection. When the protection function, automatically cut off the motor power to protect the motor is not easy to burn out at the same time audible and visual alarm. DWQ series motor soft starter, the main circuit power non-contact, no spark, no noise, vibration-free, long life, high reliability, maintenance work for a very small amount.

DWQ series motor soft starter to change the original start-up control, automatic safety and reliability control to solve the key problems. No longer having to worry about starting a larger motor with a load. At the same time, it avoids the impact caused by the change of the current, protects the mechanical system itself from damage and prolongs the service life of the mechanical system, the electrical control system and the motor.

DWQ series motor soft starter, through the computer control, improve the motor power factor, to achieve energy efficient operation.

GS microcomputer automatic control fire water supply equipment system schematic

GS microcomputer automatic control fire water supply equipment system schematic

DWQ series motor soft starter voltage and current control table

DWQ series motor soft starter voltage and current control table 1

DWQ series motor soft starter voltage and current control table 2

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