Varible Speed Controller For Wet Rotar Circulating Pump

NT3041

Does any one make a variable speed controller for a Taco 0013 pump? I know Taco has a delta "T" pump but that is more control than I need. I am looking to fine tune the pump curve to match the system. A simple knob to turn/adjust then leave once it is adjusted.





Thanks In Advance.

Jamie Hall

Sorry...

That pump has an induction motor.  Therefore, the only way to change the speed is to change the frequency of the current coming into it.  I suspect there are variable frequency controllers available.  I also suspect that they aren't inexpensive...

knotgrumpy

Looks like this Tekmar would do it...

But not cheap.



http://www.pexsupply.com/Tekmar-157-Difference-Setpoint-Control-Variable-Speed-7955000-p

SWEI

TRIAC speed control

Can work on single phase induction motors, as long as you understand the limitations.  It's not particularly efficient -- you don't save all that much energy turning them down, unlike VFD with a 3ø motor -- but it does work.  What we're talking about is in effect a smart version of a TRIAC lamp dimmer.  You have to provide full power for a couple of seconds in order to get the motor to start, then ramp down do the desired speed.  Turndown is limited in most applications, but for the special case of a circulator pump you can pulse power to the motor below that cutout, effecting near-complete control over speed.  Tekmar, Heat-Timer, Caleffi, Taco, and others do this in some of their controls.



I have a board that will do the basic "smart dimmer" function but does not handle the low speed pulsed operation.  It's not a packaged product, but it can be integrated with most any control system.

Jamie Hall

At the risk of a stupid question...

What does that do to your power factor?  Temperature rise in the windings?  Maybe it doesn't matter on a small motor like that, but I know that bigger induction motors running on reduced voltage can have some odd little problems...

SWEI

It's ugly

if you put a 'scope on it.  Efficiency drops along with speed, so of course more of the input energy turns into heat.  Given that typical single-phase fractional horsepower motors start out somewhere in the 50-60% range at full speed, it's not hard to see why ECMs made their first appearance in small circulators.

NT3041

Thanks Everyone For All Your Input

I think a delta "T" pump looks better and better.

NT3041

Smart Fan Controller

I came across this controller. Thinking it might work on a circulating pump. Adjustments could be made via the dip switches.?





http://www.smokelessheat.com/Media/FurnaceDocuments/SmartFan/Nimbus.pdf

SWEI

that's the board we're using

with 0-10V DDC outputs.  You can set a fixed rate with the DIP switches.

pipeking

swei

when do u use those controlers? and y? just tryin to learn

SWEI

circ control

I've used them to control boiler circs on DDC systems.  They cost a fraction of the adder Taco wants for a VDT or VSF.  I'd happily pony up for an ECM, but nobody makes one with curve that really matches the TT firetube HX heat loss.