Cheap way to vari-speed pump

[Phil.c]

First, let me say that I'm not an electrician, but I thought I'd try controlling my speed pump.

There are a few controllers out there like Certikin (around £350) that control speed and also have automation built in but they are usually expensive. I bought a cheap voltage controller (link below) just to try.
It was just a case of plugging it in and then plugging the pump to it with the multi socket on the front of the unit, it has pro's and con's, the pro's, it works fine, by lowering the voltage with the dial, the pump can be run very slowly, but care has to be taken not to run it at a speed which could cut it out, slow running does make the pump a little more noisy though, but all is fine so far.

The problems arise not with the unit but with modern trip fuses; I found that the pump would only run at slow speed for a few minutes before the fuse tripped out, I could only get it to stay on with the voltage as low as 165v, below that it trips. I guess that it would run a lot slower with the old wire fuses.

So, even though the speed couldn't be reduced any slower, it still runs at around three quarter speed which still adds better filtration and saves money, I would guess that even the more expensive units would still trip the fuse, but as I previously said, I'm not an electrician, but I've spoken to one and he agrees.

So to sum up, the unit is cheep but of good quality, and it now runs my pump at a slower speed.

Just thought this might be usefull info for anyone thinking of a speed control.


https://www.ebay.co.uk/itm/AC-220V-4000 ... fresh=true

[Teapot]

There is quite a difference in voltage speed reduction and PWM control which varies the frequency of the AC supply and used more conventionally for speed reduction. Whilst I must remind that Certikin do not make the controller they re badge other units. There are other units available where you can program the start up time, run speeds etc.
This is an area that really needs careful planning to maximise efficiency and the really big monetary savings you can enjoy together with big improvements in water quality.
Phil is your MCB rated for electric motor? Type C are generally suitable for motors.

[Phil.c]

I don't know if this unit is Type C as there's no info to confirm that, my fuse/control board has a timer so the voltage unit is controlled by this if needed.
There's no problem with pump speed as it can be cut right down to a quarter, it's just the trip fuse which is I guess not rated to the drop in the low voltage etc. used.

[Teapot]

Normal breakers cant take the motor load (inrush current) so Type C are used. That can prevent trips.
Lowering motor speed by voltage also drops the motor torque substantially hence why PWM is the preferred option.
Interested to know your flow rates and system pressures at various settings?

[Phil.c]

An electrician friend recommends a type B as a better option, but to me it might still be too sensitive?

[Teapot]

Well type B is way better than type A. Try it, you can still go to type C if tripping persists. Maybe your electrician can put use test meter to be sure?

[Phil.c]

Just wondering if the B breaker will fit the slot left of the timer, this is the motor fuse, it looks too recessed?

[Teapot]

Couldn't say but the central heating programmer I used to make

[Phil.c]

If it doesn't fit, there's probably a way to mount it on something outside the box.

[Teapot]

Yes Phil you could probably fit one in a garage fuse box

[Phil.c]

I thought this would be a quick swap but I've just taken the cover off the fuse box only to find that the pump breaker, the one left of the timer is part of the P25M next to it, a complete unit, there's three connectors at the top and at the bottom with quite a few wires going to these connectors, so, not just one in and one out as I was hoping, The timer is a part of these connections.