I want to control a pretty powerful water pump (900W) using an Arduino. The idea is very simple : to be able to turn on and off the device every x minutes with a timer in the Arduino code.
Before going into the programming part I wanted to first make sure that the hardware side was well designed and safe for this purpose. To simplify things, I wanted to make a switchable power socket instead of hacking the wire from the pump directly. Here is a scheme :
Since the current drawn by the pump is : I = P/U = 900/230 ~ 4A, I figured that this relay should do the trick (According to the specs it can handle up to 7A/250Vac on the output) : Module 1 relais 5V MR912 Microbot - Modules à relais | GO TRONIC. Especially because it comes with an already built-in flyback diode and a transistor for control. Is this a good solution ?
I was also wondering how to choose the specs for the transistor and the diode in case I wanted to build this circuit myself ?
If you read the relay specifications carefully, you will not see any mention of how many operations it is capable of doing. The reason is it is a hobby relay not meant for the type of control you want. Get a real industrial rated relay. Also the traces on the circuit board are not capable of operating safely with your mains voltage and current.
@JCA34F : Thanks for this other possibility ! What do you think would be the simplest way of doing what I'm trying to achieve ? The idea is literally to turn on and off this large pump every couple minutes for 10-15mins.
@JCA34F : Thanks for this other possibility ! What do you think would be the simplest way of doing what I'm trying to achieve ? The idea is literally to turn on and off this large pump every couple minutes for 10-15mins.
Best,
Tom
Every time your pump is turned off and then on will make a very large increase in your electricity bill, not to mention the rapid wearing out of your motor and pump. Time to rethink your project, or be prepared for increased costs.
@Paul_KD7HB : The cost does not matter so much, it's really about making it work here. The pump is pumping water out of a well and the problem is that the well has to refill before the pump turns back on... Right now I think that I just loose more electricity by having it run without any water in the well... And this process is probably killing the pump as well...
My first idea was to add a water level sensor, but I just figured that doing it empirically by timing the time of refill of the well might be much simpler to do...
My well is 608 ft. deep and the pump is at 520 ft. How deep is your well and at what level is your pump? Perhaps it is set too shallow.
Have you considered putting a float switch at the end of a long set of PVC pipes and running the down the well to just above the pump. That could warn you that the pump needs to be shut off for a while. Or have two float switches, one to warn you about the level and one above to tell you it's ok to turn the pump on.
The pump is not in contact with the water unfortunately, its in my workshop and the pipes run underground to the well.
And yes indeed, beforehand I had another pump in the well with the floater/switch system, but I had problems with the pump catching too much very fine sand was getting stuck... I had to design a system to filter the water for the sand particles to alleviate this issue.
The water is just being pumped for the pool or watering plants
The pump is not in contact with the water unfortunately, its in my workshop and the pipes run underground to the well.
And yes indeed, beforehand I had another pump in the well with the floater/switch system, but I had problems with the pump catching too much very fine sand was getting stuck... I had to design a system to filter the water for the sand particles to alleviate this issue.
The water is just being pumped for the pool or watering plants
Tom
Then your well is very shallow. You could have put a screen around the pump to stop particles greater than a certain size, but as you have the system now, you can easily add the float switches and run the wire underground, along with the water pipe.
