Relay control for 3 water pumps
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Dear colleagues, our company currently has 3 220KW 380VAC water pumps, controlled by ABB soft starters. Each soft starter comes with its own separate control cabinet, which is equipped with manual and automatic mode switches. When automatic mode is selected for any two of these pumps (with the third one serving as a backup – the system can operate up to two pumps at a time): 1. When the water level reaches 50%, the booster pump is started to fill the main pump; it is not necessary for the main pump to be completely filled before it starts operating. Once the pressure inside the main pump reaches the set value, one of the main pumps is activated； 2. Start another main pump once the water level reaches 75% ； 3. When the water level drops to 25%, both main pumps stop simultaneously ； 4. A flow switch is installed at the outlet of each main pump; if no flow is detected within 30 seconds, it is considered that the pump is faulty and the pump will stop automatically ； As described above, the manager wants to adopt an electrical control system and install a junction box. Due to my limited knowledge, I have drawn several diagrams, but they are not ideal. I would be grateful if anyone with more expertise could help me create better drawings. Thank you
I’m sorry, I really didn’t quite understand. If it’s convenient, please send me a private message.
Haha, I thought only I hadn’t understood it. It turns out it’s really not our problem – you just didn’t explain it clearly enough! !
Does that mean there’s no need for PLCs or anything similar, and control is handled purely through electrical circuits? There’s a simple reason: why complicate things? Besides, in the case of pure electrical control, how are water level and flow rate measured? A level switch can also be added for the water level, and a secondary meter will still be needed for flow rate; it doesn’t necessarily mean any savings.
Has the drawing been resolved? If not, please provide the specific model of the ABB soft starter. It would be ideal to have the actual drawings of the soft starter you purchased, so that I can create a schematic diagram for you