Single Phase speed controller

[MikeJhn]

Any of you guys know anything about speed controllers, I need to slow down a 5amp 1Hp pump which currently (sic) runs at 2850 rpm, I would like to slow it down to 900rpm and run longer, any recommendations?

Looking at this one: http://vi.raptor.ebaydesc.com/ws/eBayIS ... 5000&ver=0

Mike

 

[Rorschach]

Depends on the motor type, if its universal you might be able to, if it's induction then you can't. Slowing any motor is generally a bad idea, best to use mechanical means if possible.

Oh and that VFD is for 3phase motors.

 

[MikeJhn]

This is the label on the pump, seems its only single phase.

 

[Rorschach]

Yes it is. If you try and slow that motor you are likely to just overheat it and shorten it's lifespan considerably. Is the motor separate from the pump? If so a pulley reduction of 3:1 would be the best thing to do.

 

[Duncan A]

Bear in mind also that some pumps (typically centrifugal pumps) simply don't pump if run too slowly - they just stir the water. If the pump is positive displacement it will probably work OK at lower speeds.
Duncan

 

[johnnyb]

No expert but single phase motors can't be speed controlled it depends on the number of poles. Three phase motors are controlled by varying the frequency. (Vfd) . They can overheat and cheaper vfd lose torque. Hence it's best to get close using pulleys or gears.

 

[MikeJhn]

Nearly all pool pumps now days are multi speed, they have not changed the technology for years and all are controlled by something like this: https://www.jacksonsleisure.com/swimmin ... -inverter/

I have found a purpose made unit : https://www.ukpoolstore.co.uk/acatalog/ ... Speed.html

Also found this: http://www.instructables.com/id/Save-Mo ... eed-mod-t/

So it seems to be a common thing to do, just thought I would ask if anyone here had any experience of doing it, seems I will be the guinea pig.

Mike

 

[johnnyb]

I guess it's a check with the manufacturer of the motor first. Vfd are very useful. Even allowing overspeeding. But every motor I've ever speed controlled( on lathes mostly) was 240v three phase. It's basically digital control of the Hertz of the supply. So 240v is split into a rotating mimic three phase supply. Mains is around 50hz and can't be changed ( due to the generator spinning at this speed) But digitally any frequency can be used also slow start/ stop etc. The reverse is also used to plug solar panels into the national grid.

 

[MikeJhn]

Thanks to "sideways" I have now found this: https://www.motorcontrolwarehouse.co.uk ... 42-01.html looks to be a another contender.

Mike

 

[MikeJhn]

E-mailed Invertek and they came back to me immediately, very gratifying , unfortunately then need to know a couple of things that I do not have access to at the moment, so this will be ongoing for a couple of months before its resolved, but very optimistic that and Invertek E2 or E3 will be my VFD of choice. Invertek also have a software app that allows off site configuration and downloading to the drive, I love that sort of thing, sad isn't it, bit like apostrophise in the wrong place.

Mike