Fire water supply equipment is a fire pump, piping, valves, and a meter cabinet and other components. Factors that affect the reliability of the fire water supply equipment is multifaceted.From the perspective of the mathematical probability of starting to arrive at reliable conclusions it is commonly used methods.

1,direct startup mode 

 

Direct lines with minimal start-up mode devices are passive devices, this start-up mode to start the fire pumps are the most rapid and maximum starting current of the transformer capacity requirements of the grid is also the largest, consider starting characteristics of the motor to the pump currently in use better, and because the square-load pump can also be regarded as light-load start, it can be considered for low-voltage motors single motor power up to 90kW, for high-voltage motors (6kV or 10kV) power range up to several megawatts. When the fire pump overload occurs when an overcurrent condition, based on the type of thermal magnetic trip protection, but it's thermal relay in the action, "only the police, can not afford to brake. This mode is the easiest, most economical and reliable way to start.

2,Star - delta start-up mode

 

Star - delta starting line way more direct way to start a little more complicated, but also passive components are usually completed within a start-up time 60s, start-up current more direct way to start small. Therefore, it can be considered a single motor power can be set up to 110kW, and this line is used only for low-voltage motors. When the fire pump overload occurs when an overcurrent condition, based on the type of thermal magnetic trip protection, but it's thermal relay in the action, "only the police, can not afford to brake; Since the line a little more complicated, the probability of failure is higher than the former.

 

3,autotransformer start mode

 

Autotransformers Start mode line complex than the first two, are also passive components, generally start time may be in the 90s to complete its start-up current is also smaller than the first two, so this way the single motor power range of up to 160kW so, this line is used only for low-voltage motors. When the fire pump overload occurs when an overcurrent condition, based on the type of thermal magnetic trip protection, but it's thermal relay in the action, "only the police, can not afford to brake." Since the first two lines are more complicated, failures the probability is higher than the first two.

 

4,KB0 startup mode

 

KB0 way to start is to start a passive way, it is the circuit breakers, contactors, overload relays, disconnectors separate components of the main functions of integration and the ability to integrate multiple signal, control and protection features inside the product from the match . Has a small, short-circuit breaking performance, high operational reliability and long life electromechanical, safe and convenient to use, the advantages of energy-saving materials and so on.However, since the device only to the nominal current rating 125A, there is no high-voltage products, can only be used in low-power and low pressure fire pump is limited. In addition, the need to pay attention, in the selection, be sure to choose fire protection products. Because, when the fire pump overload, over-current, the device "can not afford to brake, only the police", in line with the fire pump control and protection requirements. This applies to low-power mode in case of fire pumps, to significantly improve the reliability, better than before in several ways, while the costs will be higher than some.

 

5,soft-start mode start

 

RQ device that is soft starter. This is an active way to start, compared with the first few lines were complicated. In this way the biggest advantage is no start-up current, the start time can be set at 0 ~ 3600s convenient according to the pump motor power, the power range of up to several hundred single motor kilowatts, due to the device, this approach mostly for low-voltage motor (there are reports on the application of high-pressure pump), also adaptation EPS power supply.

 

Because of its protection is electronic, the fire pump overload, overcurrent, supply undervoltage, lack of equal reason it will immediately enter the protection, turn off the output, which is characteristic of endogenous device.In case of fire, once the fire pump power overload or overvoltage, undervoltage, fire pump will stop running immediately. So its reliability over the previous several ways somewhat less.

 

6,the drive start-up mode

 

When used in high-pressure pump, you need to configure the appropriate input and output transformers. This is an active way to start the line level is the way to even more complex with some soft-start.Is no start-up current, the starting time can be easily set arbitrarily,a single motor power and motor voltage range up to several megawatts and 10kV. Also adaptation EPS power supply power supply.Because of its circuit complexity, particularly the drive has borne so its reliability over the previous few who are poor.