Hi. I am trying to achieve a partial vacuum of under 10 micron Hg and I noticed that the options for vacuum pumps become exponentially expensive. Normally there would be volumetric flow performance and efficiency requirements involved but this is simply a bench scale/proof of concept vacuum. I...
This problem sort of reminds me of high school physics. The ol' mass on a spring problem; however, the frequency of oscillation "resonance of dampening" is related to mass, "r", and "k." Mass is approximately equal to check spring mass so long as there are few line losses.
Is this a known...
I noticed some products concerning BLDC drive microchips and such.. Can't seem to find a simple drive.
Now correct me if i'm wrong, but can't you put a dc source onto a sensorless bldc control and drive any 3 phase "a/c" motor on that?
My reasoning is that solar driven dc fans (attic...
I have this solar thermal recirculating pump that meets all necessary spec's (1 GPM, 20ft head, and 35W solar panel). All of this but it is too noisy for residential use at 6800RPM. A high pitch whine is unacceptable on a quiet day.
I've tried different boxes. The more deadening, tigher seals...
I have a BLDC motor built by ebmpabst. It is magnetically driving a fluid-o-tech gear pump (they came together).
I am trying to run this off of solar panels and I had a custom board built by solarcontrols.com in order to drive this motor.
The ebmpabst motor is driven normally by "variodrive"...
3-4 GPM max 10 micron filter for water up to 180 deg F.
It is insane what some of these companies are asking- mostly hot tub companies with 10 inch cartridge filters. Way larger than necessary. This is just a filter to keep stuff out of a positive displacement (gear motor) pump. It's...
I am trying out all different sorts of bags to encapsulate a wax (ester) "pentaerythritol adipate stearate" which melts at around 135F. The bags are to store heat in the phase change region and over a temperature range of between 100F and perhaps as high as 190F. I have been having problems with...
Historically a LCB (linear current booster) is used to power a solar driven motor so that it will start at low voltage (earlier in the day where little sunlight is available).
LCBs are prone to failure and they tend to burn out motors. Before just recently, LCB's were economically beneficial...
I am trying to find the appropriate pump for my design. Simply, there is a hot water storage vessel open to atmosphere.
The water may be from 65-90C.
The elevation before the pump is 5 feet.
The elevation after the pump is 15 feet.
The required flowrate is from 0.5-10 GPM.
The return path...
I must cut my project to my variable speed pump for some odd reason. The BLDC is appropriate for my purpose as water in an open loop circulating pump must overcome a very high initial head and throttle back to very low speeds. It makes little sense to use an A/C motor. This operation is...
Hello. I'm having a controller developed for my process, a solar thermal collection tank (a tank full of hot water).
The liquid level is controlled using a high and a low sensor. I am using conductive probes (no moving parts and relatively inexpensive); however, all commercially available...
I've tried to educate myself on what will make the proper pump for my application, and I believe to have figured it out but I can't seem to find what I'm looking for.
I need a very small pump (65-100W) to drive hot (180F) water through domestic hot water solar panels. The panels are a somewhat...
Can someone please help me understand the practical meaning of these two "terms" or "methods"? Let's put it into context:
In order to control a, say BLDC 1/10HP motor one needs a DC motor drive. In my case 115VAC power source and an output DC voltage of 0-90VDC usually, for a 1/4 HP motor...
Hi. I'm trying to design a controller to control a VFD that is intended to drive a circulation pump. The pump circulates water in an "open loop" 1/2" pipe through solar panels. The setpoint is a differential temperature accross the panels. The control method will be P-I-D.
First, is there any...
