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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...

tmoose- the answer to your query is yes.. it only becomes objectionable at the high end of the rpm range. nonetheless, and unfortunately, the flowrate is just about right at just about all times of the day. this is somewhat of a "variable speed drive" due to the differing light conditions...

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...

It is apparently impossible to find a BLDC 1/16hp (circa 35-60W) motor that runs in the correct rpm range (800-1750rpm or so?).... and if i do (bodine-electric) its commutated at 60 degrees instead of 120, and its $232!!!!!! yikes! i think that Papst may have one but they're impossible to...

dickon- thanks! i talked to oberdorfer and got ahold of a lip-seal type which i was told has very low drag. the packing they normally use to "seal" the pump is designed to drip. intersting. anyways for $168 it seems pretty tasty. brings production costs down 20% on the motor/pump assembly. if...

edit: looked at oberdorfer. looks similar although the pumps available appear to reach 1gpm only with 120 watts or so, unlike the fluidotech pump that i found which requires a mere 35W.

hydtools you're absolutely correct. I've been using automotive rubber hosing for the input. Initially we went with this. Then, we decided that plumbers would have a fit if they noticed something that wasn't a standard plumbing connection. Finally, we decided that they will have to deal with it...

unfortunately, it requires a 1/3HP centrifugal pump to overcome a 20ft head. Also, the pump can't be mounted above the fluid level without a snorkel or trombone or something of that sort. Extra traps and valves cost money and lead to more failure and uncertainty. If we manufactur these than we...

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...

Alas.. it may.. but, in this case what I did was re-connect the embpabst and use my voltmeter, while spinning the motor against its will, by hand. One of the hall sensors gave 0 (null) for the entire 360 degrees. Further, when disconnected, and "ohmed out," the same hall sensor gave me 46 ohms...

According to the commutation specs (revisiting them), I still fail to see where 111 or 000 is a legal state for the embpabst motor. I'm going to plug that one back in and check the dead spots.. Could it POSSIBLY be two DIFFERENT causes and the SAME effect...

34B Brushless DC Series Motors (1/5 - 3/8 HP) Motors may be used with a variety of controls, including servo amplifiers, that produce square-wave current for 3-phase, 4-pole brushless motors with 60° commutation I can't contact any of the reps right now since everything is Eastern... but...

Ok. I talked to the developer of the controller He said something to the affect that the motors are causing this problem (imagine that). Well... I've come to realize that I understand electricity and computers just about as much as a really smart silverback gorilla. Hall sensors are...

Ok. Roger that. I checked the voltage on the halls and they all read 6.1 Volts +/- 0.1 Therefore, sreid I believe that you are correct in your assessment. Since they are in an illegal state, does that mean that the controller algorithm is jacked up a bit? Woah is me.. woah is me. THANK...

Okay. I will do that right now. For the record, I pulled out a spare "Baldor" 1/6HP BLDC motor and downloaded the commutation information. Hooked it up and it does the SAME thing, leading me to believe that either the two motors are malfunctioning in the same manner, the controller is...

Looks like the terrorists have won

Okay, well there is another problem here. On solar panels, and on 18V 1.1A power supply (which I was told would be sufficient for testing), the motor runs ONLY when you tap it into the right direction... or in the wrong direction. There are 3 "dead spots" around the motor where there is no...

She works! So... basically.. i'm an idiot; however, this dialogue/monologue encourages me to contine my quest. Thanks for your help everyone as usual! I hope to one day help someone else out ;)

Thanks for letting me pad my own posts as i think aloud; however, after reviewing the apparent paradox, I determined that the diagram provided to me shows pin positions with respect to the motor oriented from the opposite side to which I had originally thought. it appears that VCC/GND/RLG3...