Cheap VFDs for three phase pumps

[Jpadie]

Hello all
I've been using a cheap vfd (<100 EUR) with a normal 3 phase pump as a variable speed pool pump for a few years. Works well.

I've developed a modbus interface in node red to control the pump remotely. It's in a "works for me" state but I was wondering whether others might be interested? In which case I'd tart it up and make it available.

Let me know!

 

[jakeblat]

Would be interested to know what pump and VFD you are using.

I looked into variable speed pumps and in the UK the options are limited and very expensive. I don't think I would ever see a return on investment on a variable speed pump even with the high electricity prices here.

I took at look at some off-the-shelf pool specific external speed controllers but a standard VFD did seem like a better option, especially as most offer modbus or some other serial control.

 

[Jpadie]

the pumps is a Hayward clone 1.5HP. here. My pool is a smidgeon under 100m3.
the vfd could be any cheap mono-tri variant. the one I've bought in the past is here (price has gone up a bit). This version sometimes comes with two modbus ports and sometimes only one. no way to tell in advance, sadly. the downside of only having one port is that you lose the ability to use the operating panel.

the pump provides reasonable flow operating at 25Hz, which provides a significant reduction in energy costs.