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Varible Speed Controller For Wet Rotar Circulating Pump (11 Posts)
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Varible Speed Controller For Wet Rotar Circulating Pump
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.
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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...
Jamie
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
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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.
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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...
Jamie
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.
Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
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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.
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Thanks Everyone For All Your Input
I think a delta "T" pump looks better and better.
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that's the board we're using
with 0-10V DDC outputs. You can set a fixed rate with the DIP switches.
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swei
when do u use those controlers? and y? just tryin to learn
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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.
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