[chbot] 3 phase motor drive

Robin Gilks robin at gilks.org
Fri Jul 15 00:53:49 BST 2016

Greetings all

My project to make a 6kw 48vDC to 240vAC inverter is nearing completion so
I'm looking at ways to drive my irrigation system to make the best use of
my solar PV power (rather than just export it).

The well pump is 3 phase 4 hp (i.e. 3kw) but of course the inverter output
is single phase.

I'm thinking that a Variable Frequency Drive, designed to operate 3 phase
lathes etc, would be a better (i.e. more efficient) way of getting the
conversion than a 10hp 3 phase induction motor and a stack of capacitors
as a rotary converter.

I've had a quick scan of aliexpress and similar but there is a lot of
ambiguity between input and outputs volts (I'm looking for 240 in and 440
out) and there seems to be a step in price when going over 2kw.

Firstly, does anyone know if a VFD is suitable for this application
Secondly, does anyone know of a second hand unit at a reasonable price.


Robin Gilks

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