What options for a variable speed pump?

[Ralph]

Looking at options for pumps I see that most people go for the magnetic drive centrifugal type pump and throttle them using a ball valve.

I would prefer a pump that I can vary the speed of rather than just choking the output. Is it possible to fit a speed controller to the standard centrifugal pump? Or can you buy variable speed pumps? What options are out there?

[Mike Neilson]

Stick a speed controller on it. However I wounder about the size of the pump needed for a homebrew size and slowing that down, wounder if it will get blocked to easy?

[Ralph]

wort is pretty thin... I doubt it would get blocked too easy??

What sort of speed controller? Is it a separate piece of electronics you can simply pick up??

[Mike Neilson]

Yeah dude you can get them from john brooks, its not the wort but little chunks of malt and whole hop pallets thst seem to block it up 

[martin w]

keep an eye on trade me for vfd or vsd-variable frequency/speed drive i believe you need a 3 phase pump but the vfd lets you power it from single phase,this is how the brewer at the local micro has his pump.maybe it would work with a single phase pump?- you'd need someone who understands electronics to go into more detail.

can you control peristaltic pumps?there's a thread somewhere on here where the guy made his own!

i think most people go the magnetic drive option because when cost,batch size and ease of use are taken into consideration it comes out the winner,all the other options i looked at were either too expensive for me or overkill for the brewery size.

[Pat Fuller]

I picked up a Hot water booster pump off TM for bugger all, $1 reserve. My plan is to use a speed controller as its only 90 Watt pump. I can get speed controllers for about $45. As I'm still only building my set up at the moment haven't tried it yet. I figure Ill try this first and if it doesn't work ill have to invest in a magnetic drive pump.

[Smiffy]

How you control the speed depends entirely on what type of motor it is, and there are many different kinds of motor. See http://en.wikipedia.org/wiki/AC_motor to get an idea of some of the variations. Many of these would need a different type of speed controller.

Using a magnetic drive centrifugal pump and controlling the flow with a valve is probably the most reliable and economic way to do it for a small motor. Both factors mean that you can't overload the motor, and power consumption will be small enough not to be a concern.