First, frequency control
The frequency conversion control is based on the pressure of the pipe network. The remote pressure gauge feeds back the pressure signal to the inverter for PID calculation, and then the frequency conversion output changes the motor speed to achieve constant pressure. This method not only has constant pressure but also saves energy (the working current is small, especially when the flow rate is small, the pump can stop), and the performance is superior.
Second, manual operation:
The switch to the fire pump manufacturer 3SAC is placed in the "manual" state, at which time the pump can only work manually at the power frequency. When the power is turned on, the power indicator of the control cabinet is on. Press the 1# pump “Start” button, the 1# pump motor starts running, and the “1# pump power frequency” indicator lights. Press the 1# pump “stop” button, the 1# pump motor stops working, and the “1# pump power frequency” indicator is off. When the transfer switch of the control panel panel is placed in the "manual" position, the start and stop of the water supply device can only be manually controlled via the "Start/Stop" button on the control cabinet panel. At the same time, the indicator light shows that only the “Power Frequency Indicator” is valid. Other situations are similar. If the inverter is not started, the manual operation is started by the soft starter.
Third, automatic operation (controlled by PLC):
The transfer switch 3SAC is placed in the "automatic" state, and the pump's automatic allowable knob switch is turned to the "on" position. Only when the automatic allowable knob switch of the 1# pump is in the “on” state, the 1# pump can participate in the work (frequency conversion or power frequency). Other work situations are similar. When there is a fire alarm (controlled by the fire center remote control or fire hydrant box button), a start signal is sent to the control cabinet. At this time, the PLC receives the fire signal, and after a certain delay, stops the water supply to the living area, and the system works with the fire pressure. The frequency converter drives the water pump to supply constant pressure water to the fire fighting equipment.
Fourth, it also has other functions:
A.Automatic plus / minus pump function B. Failover function
C. Knob switching function D. Timing automatic rotation function
E.Water shortage protection function F. fault indication function
A. Automatic plus / minus pump function
When the power is turned on, the power indicator of the control cabinet is on. When the pool is not short of water, after a few seconds delay, the 1# pump motor automatically starts to run. In the case that the 1# pump water supply can not meet the external water supply, the system automatically adds the pump, automatically converts the 1# water pump into the power frequency operation, and delays the automatic frequency conversion to start the 2# water pump. When more than one pump is in operation (ie: there are multiple pumps running), and the water supply of the pump is greater than the user's water consumption, the system automatically reduces the pump, and the principle of reducing the pump is “start first and then stop”, ie: The pump work first should be stopped first. After this continuous dynamic adjustment, until the system water supply pressure reaches a certain balance.
When the 1# water pump frequency conversion running signal is output, the feedback signal is detected by 1 second delay. If the feedback signal is still not sucked, the output of the 1# water pump frequency conversion running signal is cut off, and the pump is automatically switched to the next stopped pump. An alarm signal is issued. After troubleshooting, press the “Fault Reset” button (a pulse signal) on the control cabinet panel to release the fault signal of the PLC memory, and the fault signal indication is extinguished. The other pumps have the same frequency conversion work.
C.Knob switching function
When the 1# water pump frequency conversion running signal is output, turn the automatic allowable knob switch of the 1# water pump to the “off” position. At this time, the 1# water pump frequency conversion running signal is turned off, the running signal is extinguished, and the automatic switching to the next station is stopped. State of the water pump. The other pumps have the same frequency conversion work.
D. Timing automatic wheel fire hydrant pump replacement function does not require timed switching function when firefighting
When the 1# water pump frequency conversion operation signal is on, and the other constant pressure pump is in the stop state, after a certain period of time (set in the PLC for 24 hours), it will automatically switch to the next water pump 2# to make it run in frequency. At this time, the automatic permission knob switch of the two constant pressure pumps must be in the "on" state. 2# pump frequency conversion work is similar.
E. Water shortage protection
The availability of the pool water source will directly affect the start and stop of the system water pump. When the pool is short of water, disconnected, the system will automatically stop the operation of the pump (power frequency and frequency conversion).
F. Fault indication function
When each pump fails (such as overload), the system automatically stops the output of the corresponding pump in the PLC, cuts off the power of the motor, terminates the motor operation, and gives corresponding indications of the fault.