Powered by Invision Power Board


Forum Rules Forum Rules (Please read before posting)
  Reply to this topicStart new topicStart Poll

> Brushless Motor As Generator?
rayder
Posted: August 25, 2011 11:33 am
Reply to this postQuote Post


Sr. Member
*****

Group: Trusted Members
Posts: 261
Member No.: 5,009
Joined: May 01, 2006




hey guys just looking for a bit of info. i was looking at doing a little home power generation and was wondering if anyone can give me some pointers on possibly using an rc brushless motor to generate power. and i'm well aware that its not going to power my whole house lol. all of the brushless motors i've looked at have a kv rating and the explanation i found on that was k = rpm and v - volts, so a 4500kv motor would spin at 45,000rpm when powered from 10v. now thats all well and good, but does that mean i would need one that was rated at < 1kv? or am i missing something? btw just attempting to generate 12v dc atm.
PMEmail PosterUsers Website
Top
CWB
Posted: August 25, 2011 01:59 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 21,384
Member No.: 15,154
Joined: May 15, 2008




man , usually stuff that spins that fast has to be very well built to last ... i don't think an r/c motor falls into that category .
"gearing up" to spin it that fast is going to be a PITA .

you might look into using an old car alternator as the basis for a 12 volt generation system .


--------------------
"Know how to solve every problem that has been solved"
R. Feynman '88
PM
Top
johansen
Posted: August 25, 2011 02:03 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,153
Member No.: 10,912
Joined: September 06, 2007




the small ones really do spin that fast. think the max is about 60 k though before the bearings burn up.

what is the energy source? and what is its native rpm?




--------------------
9/11 was really a prototype steel smelter that runs on naturally aspirated jet fuel and phosphorus.
PMEmail PosterUsers Website
Top
tekwiz
Posted: August 25, 2011 07:01 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




You won't be able to use a brushless motor without modification. This will include removing the original drive circuitry, then adding a rectifier. Most brushless motors are 3 phase, so the rectifier will also have to be 3 phase.
Most motors must be spun 15-20% faster than rated RPM in order to produce rated power as output.
If you want to produce 12V, then it's best to start with 12 volt equipment.
Either a car alternator, or one of the newer permanent magnet starter motors would be good choices to start with. The starter would probably begin to produce usable output at a lower RPM than the alternator, but won't be able to handle as much power on a continuous basis.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
MacFromOK
Posted: August 25, 2011 10:30 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 14,133
Member No.: 5,314
Joined: June 04, 2006




QUOTE (tekwiz @ August 25, 2011 01:01 pm)
Either a car alternator, or one of the newer permanent magnet starter motors would be good choices to start with.

A starter motor's bushings (sleeve bearings) may not last very long, as they're designed to run for a few seconds at a time, not hours/days (though the load would be much less than starting an engine, and I have seen older ones drive refueling pumps). You could probably have custom end-plates made with ball or roller bearings, but it would drive the project cost up a bit.

An automotive alternator will generate up to 120VAC or so (maybe more?) unregulated, but it's 3-phase. You can get lots of power at 12VDC though.

A vehicle's heater/AC fan motor should make a good 12VDC small-ish generator, and they're designed for long run times.

You can use single-phase AC induction motors for generating electricity, but there's a narrow speed range for output, so they're not ideal for wind-driven (or any other variable speed) power. But if you want to know the basics, here's a site where the guy drives them with small engines (somewhere around 8% over their rated speed):

http://www.qsl.net/ns8o/Induction_Generator.html

Let us know how it goes. beer.gif


--------------------
Mac *

"Basic research is what I'm doing when I don't know what I'm doing." [Wernher Von Braun]

* is not responsible for errors, consequential damage, or... anything.
PMEmail Poster
Top
rayder
Posted: August 26, 2011 08:42 am
Reply to this postQuote Post


Sr. Member
*****

Group: Trusted Members
Posts: 261
Member No.: 5,009
Joined: May 01, 2006




thanks for the info guys. the reason i was looking at brushless motors was because they can be rather small and as a plus, brushless. i know i can use an alternator to make everything simple but i was actually looking at making a device that sits inline with the main water supply pipe to our block so that as water is used anywhere in the house, the pressure from the "new" water coming down the pipe would generate power. i know it wouldn't generate heaps, but for the sake of thinking green etc, you could have multiple devices like this around the home generating electricity basically for free as it is passive generation. anyways, thats why i was hoping to use a smaller motor, so that its not so bulky and ugly hanging off the water meter or inline with the pipe. any suggestions for something smaller than an alternator? and ac/dc does not matter as both are usable.
PMEmail PosterUsers Website
Top
Gorgon
Posted: August 26, 2011 10:00 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 3,009
Member No.: 3,861
Joined: December 18, 2005




That's brilliant, flush your toilet to see the soap on TV laugh.gif it's the wrong order but who cares thumbsup.gif

TOK wink.gif


--------------------
Light travels faster than sound. That's why some people appear bright until they speak!
PMEmail Poster
Top
MikeGyver
Posted: August 26, 2011 10:47 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Trusted Members
Posts: 1,273
Member No.: 12,151
Joined: December 05, 2007




Sounds like the turbine is going determine what motor you can use to a degree, and probably be much more important of a decision anyway. What are you going to use?
PMEmail Poster
Top
CWB
Posted: August 26, 2011 12:27 pm
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 21,384
Member No.: 15,154
Joined: May 15, 2008




"... so that its not so bulky and ugly hanging off the water meter or inline with the pipe ..."

hmmm ...
is this a privately owned system (as in you own it) or a "utility" system ?
you may run into problems with "unauthorized equipment" , tampering with a utility , etc .
there is also theft of service (much the same as the electric companies do not allow the stealing of power from their transmission lines by "induction") .
remember : no free lunches
placing a turbine in line with the water supply to generate power will "consume" energy ... that energy was "put into the system" by the pumps of the water company ... they pay for the electricity to run those pumps .

think of it like hooking a small vehicle to the back of a semi as it pulls out of the parking lot ... the energy to pull you along comes out of the diesel in the semi .
and the driver aint going to be none too happy when he finds out ... by way of reduced mileage and a slower response of his rig and things will get ugly real quick .
you might want to check with your HMO to see if this is covered .


--------------------
"Know how to solve every problem that has been solved"
R. Feynman '88
PM
Top
rayder
Posted: August 26, 2011 03:17 pm
Reply to this postQuote Post


Sr. Member
*****

Group: Trusted Members
Posts: 261
Member No.: 5,009
Joined: May 01, 2006




i would assume that there would be no theft of service involved as the device would be placed after the water meter, thus not allowing the theft of water. especially seeing as we pay for water as a service so anything that happens to the water after it passes through the meter is entirely up to me. but even if it weren't from the main pipe, if the device was small enough you could put it on any pipe that carries water out of something else even though it would usually carry less pressure such as down pipes from your roof if you lived in a wetter than average area, the outlet pipe from your washing machine, drains in and around the home etc. by themselves they may not generate much but with a few of them placed in appropriate spots they may be helpful. and they've been pushing renewable energy and eco awareness in australia for several years with government rebates in solar etc and compulsory environmental certificates for all new houses built which gets tighter every year so i started thinking of other ways to harvest otherwise unused potential energy from around the home. another idea i had was tiles/flooring laid with piezo electric sensors as they generate electricity through touch and vibration. so just walking around the house is going to transfer your used energy into a small amount of harvested energy.

not sure how the turbine would dictate what motor or type of motor i could use mike, care to elaborate?
PMEmail PosterUsers Website
Top
tekwiz
Posted: August 26, 2011 06:13 pm
Reply to this postQuote Post


Forum Addict ++
Group Icon

Group: Moderators
Posts: 28,711
Member No.: 5,746
Joined: July 24, 2006




If the output of such a system were to exceed the few milliwatts range, the pressure drop would be so bad as to reduce flow to a trickle from your faucets. The energy to produce power has to come from someplace, & if there isn't a huge flow to work with, it all has to come from a pressure drop.
TANSTAAFL. wink.gif


BTW: You would get much better results from a few micro wind turbines, based on salvaged table fan blades. You'll get a lot more power from these, without any water issues. The nice part about lots of small wind turbines is that they can be mounted in places that take advantage of your house's aerodynamics.


--------------------
Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring.
To him, mere toys of the moment, to be overturned at the flick of a finger.

Fortuna favet fortibus.
PMEmail Poster
Top
MacFromOK
Posted: August 27, 2011 12:06 am
Reply to this postQuote Post


Forum Addict ++
*******

Group: Spamminator Taskforce
Posts: 14,133
Member No.: 5,314
Joined: June 04, 2006




This topic has come up before. I think about the best you can expect is one of those ready-made showerhead units that powers an LED... biggrin.gif


--------------------
Mac *

"Basic research is what I'm doing when I don't know what I'm doing." [Wernher Von Braun]

* is not responsible for errors, consequential damage, or... anything.
PMEmail Poster
Top
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

Topic Options Reply to this topicStart new topicStart Poll

 


:: support us ::




ElectronicsSkin by DutchDork & The-Force