alien
Well-Known Member
It can handle a bit of gunk. There is an internal impeller where tiny bits of grot can stick here and there but the usual cleaning routine is enough to deal with it.
Since these are DC (direct current) and not AC (alternating current) a simple speed controller will work. You cannot do this with AC motors because it changes the wavelength of the power and it throws the timing off in the motor.
http://www.ebay.com/itm/12V-Dc-Moto...797?pt=LH_DefaultDomain_0&hash=item27cff09fc5
http://www.ebay.com/itm/12V-24V-36V...692?pt=LH_DefaultDomain_0&hash=item337a7582fc
Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors which are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor (AC, alternating current, does not imply a sinusoidal waveform but rather a bi-directional current with no restriction on waveform); additional sensors and electronics control the inverter output amplitude and waveform (and therefore percent of DC bus usage/efficiency) and frequency (i.e. rotor speed).
If these are brushless DC motors, you may need more than changing the voltage to reduce the rotor speed. Anyone try it yet?
http://en.wikipedia.org/wiki/Brushless_DC_electric_motor
Code:Brushless DC electric motor (BLDC motors, BL motors) also known as electronically commutated motors (ECMs, EC motors) are synchronous motors which are powered by a DC electric source via an integrated inverter/switching power supply, which produces an AC electric signal to drive the motor (AC, alternating current, does not imply a sinusoidal waveform but rather a bi-directional current with no restriction on waveform); additional sensors and electronics control the inverter output amplitude and waveform (and therefore percent of DC bus usage/efficiency) and frequency (i.e. rotor speed).
Unless you need a higher flow rate then most brewers go for the 8 watt as it is the best value. So long as the PSU outputs DC and at least 750 milliamps then it will work well with the pump, allowing you to tweak the flow rate to suit. It is also fine to restrict the flow physically with a valve, you won't burn the pump out or strain it.
DrHops said:I just bought one of the topsflo eBay pumps for $75 with free shipping. The threads are NPT 1/2 inch stainless steel. I'm still piecing it all together but I will be using a ball valve after the pump to control the flow. The valve costs $12, I'm not sure why I'd spend more or have to make something that will in effect do the same exact thing as a ball valve will. I'm somewhat handy, but sometimes simple is just better.
This is a quote from an email from the solarprojects.co.uk rep:
So you don't necesarily need a bypass valve to adjust the flow. Restricting the power (by PWM e.g. LED dimmer) or an inline valve will also work.
tre9er said:Colonel, you're controlling flow with ball valve...does this seem to be a viable option or has anyone installed a dimmer or potentiometer? I'd consider these even if just for transfer as it takes forever to move liquid via gravity.
I would love to speed up various parts of my brew day and emptying the tun via gravity takes a long time.
Surprised it takes that long to empty using gravity? How much drop do you have to the exit tubing? I am always one to speed things along but never had this issue. Does your tubing from the MT extend all the way down to the wort level in the cooler?
By the way, it is my understanding that the impeller and other plastic parts are polysulfone same as the March and Chugger pumps.
It is a plastic called Fortron as far as I know, which from a quick googling:- Polyphenylene Sulfide (i.e.; Techtron, Ryton, Fortron); seems to be another name for the same thing. It is fully food safe.
HDIr0n said:Man the wait is killing me, it has been 3 weeks since I ordered it. They must have put it on a row boat coming from China.
On another note has anybody secured these to their brew stand or some other fixture? I am thinking about using U-bolts to secure them to my stand. Also I think I am going to put a 3 way valve on them to be able to run my Brutus 20 setup.
-G
tre9er said:I'm not pump-literate, so does the ball valve need to be on the OP side to regulate flow or can it be on the IP, or does it matter?
Ball valve needs to be on the outlet side
The mag drive isn't so much the reason they can be throttled as the centrifugal impeller part. The mag drive pumps aren't decoupling when they are throttled, the impeller are just thrashing the product. That said, controlling the speed is a much more elegant solution, and doesn't beat up your product (wort) as severely. This can be done using PWM controllers for the March/Chugger AC pumps as well these DC ones, or even a cheaper TRIAC based speed controller for the AC powered pumps.Because these are 12vdc it would be simple to use a voltage regulator to control the speed of the pump. Since they are not magnetic drive I probably wouldn't adjust the flow with a ball valve.
Except that the pot would need to dissipate much more power than a stir plate pot for a muffin fan.Great idea! A simple inline potentiometer like the ones used on the diy stir plates might do the trick.
PWM speed controllers pulse at much higher freqs than you are stating, and appear continuously variable. PWM also gives much more range of speed (low end) for pumps/fans than varying the voltage, and are the preferred speed control solution for these applications (for DC and single phase AC, at least). They are also easier on the motor.Pulse Width Modulation (PWM) controls by changing duty cycle between full-on and full-off states. It s the best solution to control something like a heating element which is difficult to put into a controllable intermediary state.
Using PWM with a pump would mean having the pump start and stop for varying lengths of time (for example, on for one second and then off for 9 seconds out of a 10 second period).
If these motors have a flow rate proportional to voltage applied, that would be a better way to control them - this way you could have a variable and continuous flow rate rather than the repeated on-and-off interrupted flow you would get with PWM.
For anyone who has one of these pump, the easy way to check if they will support variable speed would be to put a potentiometer (variable resistor) in the circuit and check if the pump flow decreased as the potentiometer is dialed to higher resistance (less voltage to the pump). You could also just hook it up to a single 1.5V battery (or 2 1.5s in series to make 3V) and see if it pumps but at a lower flow rate...
-fafrd
The simple TRIAC based speed controllers (ceiling fan controllers) will work well with the AC pumps, but the speed range will be less than an AC PWM controller. WalterAtMarchPumps has a few posts on the topic.Since these are DC (direct current) and not AC (alternating current) a simple speed controller will work. You cannot do this with AC motors because it changes the wavelength of the power and it throws the timing off in the motor.
PWM is the preferred choice, even for the March/Chugger pumps, though I am not sure if you are talking about a brushless DC March pump. I haven't looked into those, but I would be surprised if PWM wasn't the preferred choice for those as well.People are controlling these things by PWM instead of diverting the flow. Whether that's the right thing to do, I don't really know, but it is not what is recommended for the March pump which is brushless.
I got the black pump in today. I can say already, just from loosely screwing on a few pieces that the inlet and outlet threads seem different. I easily got 3-4 threads on the outlet, but maybe 1-1.5 on the inlet before meeting resistance. This could just be a production quality problem as well.