240watt Eco Blue DC pumps

mike31154 · #1 03-09-2012, 03:38 PM

Found some additional info on another web site, specifically max head pressure for each model:

Model MaxFlow(gph) MaxWattage Maxhead(metres) Price

BlueEco240 4840 240 9 689.95

BlueEco320 4840 320 11 795.00

BlueEco500 7000 500 11 1175.00

BlueEco900 7700 900 13 1395.00

BlueEco1500 9240 1500 16 1495.00

9 meters of max head for the 240 is pretty huge, that's > 30 ft.

Info is a way down on the following web page. Took a while to load, not sure what's up with that.

http://www.koicarp.org.uk/koi_dry_goods_water.htm

The Codfather · #2 03-13-2012, 03:25 AM

Mike,
I pulled this out of the email they sent:

"the power module uses true sine wave technology for high reliability. Unlike brushless DC motors with square wave technique"

Don't quite know what that means as I'm a plumber not an electrician. Care to shed some light on this?

Pumps curves are hopefully coming soon.
Thanks,
Bob

subman · #3 03-13-2012, 03:54 AM

cheaper inverters make a squared off sine wave, basically instead of a nice curved wave its clipped at the top. The better the inverter the closer to a true sine wave it is.

subman · #4 03-13-2012, 03:56 AM

http://www.bdbatteries.com/images/sinevsmod.jpg

mike31154 · #5 03-13-2012, 04:12 AM

Generally it's AC motors that are negatively affected by a square wave power signal. They run very inefficiently if at all with anything but a pure sine wave. This is why it's not a good idea to run your AC powerheads on a backup system with a cheaper square wave producing inverter.

Without additional details on the design specifics of this 'DC' motor, it's tough to explain why they're talking about sine wave technology, since generally a DC motor runs on DC, that is Direct Current, not Alternating. I mentioned earlier that I suspect it may really be an AC motor since they appear to be feeding it a 3 phase Alternating Current signal from the controller. It is quite possible that the motor is indeed a DC motor & the frequency of the 3 phase AC signal is so high that the motor sees it as DC. Kind of like feeding an LED, which is also a DC device, a high frequency AC or PWM signal. The LED turns on & off at such a speed, that we don't perceive a flicker at all, yet since it is turned off for a nano second, there is some power savings realized over time. Confused yet? I sure as H am. I need to do a little research on running a DC motor with an Alternating Current or PWM signal.

http://en.wikipedia.org/wiki/Pulse-width_modulation

subman · #6 03-13-2012, 04:28 AM

It is very confusing for sure I just did a quick read and there is a lot going on in the controller. single phase in to 3 phase and it looks like some form of dc out....I'm guessing lol I've been out of the electrical fields (no pun intended) for a while so maybe this is a new thing.

mike31154 · #7 03-13-2012, 04:44 AM

Ya, same here. I've done a bit of reading & it seems 3 phase DC brushless motors are becoming more commonplace due to their efficiency. It appears that most are controlled using a PWM (pulse width modulated) signal but the folks at Blue Eco have decided that a sine wave is a better design than PWM to run the motor more reliably. Probably another reason for the higher cost, since the controller would be more complex to produce a 3 phase sine wave.

So looks like my initial musings about the motor actually being AC were wrong! I must eat crow!

The Codfather · #8 03-13-2012, 04:46 AM

Well I think this may be my fault, as I see nothing in the information I have that indicates it is a DC motor. I may have just assumed that it was, but now that I look at it again, they imply it is not a brushless DC motor.
My mistake.

mike31154 · #9 03-13-2012, 04:50 AM

Right at the top of Page 6 of the manual it clearly states that the pump is run by a brushless DC motor, so no mistake, you were correct.

subman · #10 03-13-2012, 04:52 AM

Quote:

Originally Posted by The Codfather

Well I think this may be my fault, as I see nothing in the information I have that indicates it is a DC motor. I may have just assumed that it was, but now that I look at it again, they imply it is not a brushless DC motor.
My mistake.

No it does say in the manual that it is a DC driven motor.

"Short Instruction
The pump is driven by a DC-motor and, therefore, equipped with a controller. Check the following sequence when starting
the pump:"

mike beat me lol