DC Wind Turbine Motors on eBay – BEWARE
DC Wind Turbine Motors on eBay – BEWARE
DIY Wind Turbines have become very popular items in the past year. We have DIY plans for both horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT) on this site. And yes, in the beginning we recommended people take a look on eBay for used DC Motors to use in their DIY Wind Turbines.
Ametek DC Motors
Unfortunately, as the demand for DC Motors has increased, so has the supply “of inappropriate” motors. A quick search on eBay for “wind turbine motor” returns many potential items. However, in my latest scan of the motors listed, I did not see any that would work properly in a DIY wind turbine!
Buyer Beware!
Your homemade wind turbine, will likely produce around 500 rpm in average winds. You will not be producing 1000+ rpm as several “vendors” trying to sell inappropriate motors on eBay would tell you.
Pay attention to the maximum RPMs of the motor. You want a motor with the best voltage output and the LOWEST RPMs. Try to get a motor that will produce 1 volt for every 25 rpm. If a motor is rated as 130VDC with a top RPM of 5100, then divide 5100 by 130 = 39.2 … you get 1 volt output for every 39.2 rpm. This motor will not produce enough voltage to charge a 12V battery (15-16V is required) until you get very strong winds.
TLG Wind Power Products produced a guide for Ametek DC Motors. This guide compares the various Ametek modules, listing their voltage, RPM, Amps and suitability for use in a DIY Wind Turbine. They very specifically advise against the purchase of an Ametek 38 model, which I found today on eBay – where the seller claims that it’s a very good motor for wind turbines! Buyer beware.
Bottom Line
Know what specifications you need and don’t believe anyone who claims the motor they want to sell you, “is perfect for wind turbines”.
DIY Vertical Axis Wind Turbines
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Filed under: Wind Turbines
The Stats your publishing on the power output from the Ametek 30 are the numbers for the Ametek 37 or 38 not the Ametek 30 which reaches 30 VDC at 325 rpm. I know this to be fact as I have 2 up-and-running and in a recent wind-storm, 60 mph+ winds I watched the meter go to 150+ VDC un-loaded. Fortunately everything held together. That might charge a battery or 2.
The Ametek 30 reaches 30 volts at 325 rpm. The Ametek 38 reaches 38 volts at 1150 rpm. As you can see, there is a HUGE difference in the output voltage when the wind is blowing at an average speed of 5.4 m/s. The Ametek 30 will produce almost full voltage at average windspeeds whereas the Ametek 38 just barely gets to the voltage needed to charge 12v batteries.
Strange how you can get 150v out of the 38 volt Ametek 38… and I’d be furling a wind turbine long time before you reach dangerous windspeeds of 60+ mph!
hi bruce!!! it’s seems that you know a lot about wind turbines.i want to ask you if the size of the turbine matter.let’s say that i have a 60 miles/ hour wind and the blades are just 4 inch long.would that wind turbine be eficient? can you give me an approximate output? thank you very much, john
John,
Here’s the link to the equation. Plug in the numbers and see what you get:
http://www.greenterrafirma.com/wind%20turbines.html
Of course theory is very nice. In practice, I’m not sure how you would attach such a small rotor to an alternator without having a huge impact on the flow of air.
Appreciate the info guys, thanks
as a newbee into these types of ventures, i have a question about a specif type of dc motor (to be used in a small scale diy wind turbine)…
its 8 and 1/4 lbs (bigger than a bread box) with a 2350 rpm rating and 180v. 76w and .45amps with a torque of 31.2 in -oz, will this work?
with the popularization of diy turbines, dc motor availability from suggested sources have been a bit slim (or overpriced). trying other markets, but these markets lack the viable information regarding turbine usage.
thanks
Terry,
The watts and amps are far to small. If the motor is rated at 76 watts, at 2350 rpm and you are running the motor at one quarter the speed – 600 rpm, you will get one quarter the watts = 18 watts of power.
Bruce.
thank you Bruce, for the quick reply…
so what watt (ha!) and amperage ballpark should i be playing in?
You need a DC motor that gets 1 volt output for every 25 rpm or less, and in the 5-10 amps output range. Some treadmill motors operate in this range. Look for continuous duty, and make sure the RPM’s are not to high.
Yes, these motors are becoming harder to find, and more expensive…
http://www.greenterrafirma.com/DIY_Wind_Turbine.html
I am looking to make some smaller wind turbines, that would fit on top of our ice cream truck to help charge the batteries. I like the horizontal design, but would need to make it smaller as in possibly only 1 ft blades which would be outfitted on top of the vehicle. This would typically be charging when driving at 10 to 20 miles per hour, but be capable of going on the highway up to 55 mph. Being able to charge the batteries while parked would be a bonus!! I also like the rooftop design, which would lower the clearance, and be placed just above the windshield.
1. What type of motor would be sufficient to run the Horizontal wind turbine?
2. What type of motor would be sufficient to run a rooftop design wind turbine (kind of like an air water-wheel)
3. If going with the rooftop design, could I put a DC motor at each end of the axis?
Thanks guys! Love this site!
I am a novice but have built a few succesful VAWT, and I think what this article forgets when talking about sizing a DC motor based on only RPM and Volts is that it assumes you will be using a direct drive connection. However, the exmaple using the Amtek 38 can easily be used by adding a simple gear or pulley system at a 2 to 1 ratio and you will get 1 volt for every 20 rpm (19.6 to be exact) of your wind turbine. So don’t limit your motor search to just one model or rpm/volt configuration.
Hi Ed,
Yes, you can use gearing to increase the RPMs. I show a very simple method via a video on our DIY HAWT wind turbine page. You’ll also notice our gearing attempt with our DIY VAWT project – this one however, did not work. The gearing acts like a brake and you therefore we need a higher wind speed to start the beast. We are still playing with the gearing on that project – lower gear ratio and maybe more surface area.
So agreed – gearing will allow you to use “other” motors. Gearing also makes the project a bit more complex and does affect the start-up wind speed and total output. But less output is certainly better than no output.
Bruce this may be a step backwords bit its a thought
your last post was about gearing maby you could mount a secondary motor to kick the primary in while using a low end gear
you can draw the power from a smaller propleer, mounted in a hollow shaft from the primary motor shaft use a regulator to make sure it kicks every few seconds. you would only need a small battery for this like a alarm system batter and a small motor say out of a coardless drill, hell use the coardless drill battery!
You would also need a wind indicator that would “trigger” the start-up motor, so you only use this motor and battery when there is enough wind to keep the turbine running once started. For example, you won’t want the start-up motor to run on a very calm evening. That said, I believe the whole system becomes far to complex for a DIY backyard wind turbine….
hello dear sir or madam
i required dc generator motor 40 to 99 volt . kindly send me the complete price list off Ur product list
We do not sell anything on this site… we just provide information for free.
All these posts are interesting !
I found this dc motor that seems to be the best choice for only $10
http://www.com/12V-DC-300-RPM-High-Torque-Gear__Box-Motor.html#
but before I go about and buy it, I would love to hear what you guys think about it ! Is it a dream come true ( free shipping) or is it useless in a wind turbine? Thanks in advance !!! And continue the great work !
Lapo… this is a “toy” motor – 2 inches long and consumes 5 watts of power! Useless!
Really quick reply ! thanks a bunch ! I understand, I saw the rpm and the voltage so I guess I jumped to conclusions… Thanks again
hey bruce i was wondering what size wind turbine i would need to power the grow lights for my marijuana plantation..any help would be appreciated..thanks and smoke one for me
Depends on the wattage of the bulbs. Can’t say as I’ve ever tried to grow anything under lights – other than baby chicks, and they use HEAT lamps which take a lot of power.
here is a question can someone use an ametek 38 motor and instead of mounting the blades directly on the turbine just use a system of gear to accomplish the same task. Maybe a 2:1 or 3:1 ratio. Anyone have some knowledge on this?
Hi Justin,
That question was asked and answer up above… yes, you can add gearing and use a motor that otherwise would not produce the volts you need at the RPM you have available. The system becomes a bit more complex and you lose a bit of power, but some output is better than no output.
So, with motors now being hard to find, can anyone recommend a motor that is good to use and can be found for purchase
I have a question about the horsepower of a DC motor. I recently found a 1/12 horsepower DC Motor listed that also has 90/115 VDC and 1750/2200 RPMs. Does the horsepower of the motor matter in a wind turbine application? Do you think that the motor mentioned would be good in low-wind environments?
I applied the formula above using 90 VDC and 2200 RPMs and get around 1 Volt for almost 25 RPMs. Is this correct?
John, 1 HP = 745 Watts. Therefore at 1/12 Horsepower, the maximum power output from that motor would be 62 watts!
Let’s say your had a very, very strong wind and produced 550 RPM – 1/4 of the maximum output. You might have 25 volts across the output, but your amps would be next to nothing! If you put a load on the end and tried to draw more power, you’d burn up the windings in no time. Your power output would only be 15 watts.
Bottom line – forget the 1/12 HP motor… try to find something around 1HP.
i have the following motor and i will like to know if is good to make a home wind generator
1/12 Hp
95 Volt DC Variable Motor 300 RPM Magnetek NIB
can anyone let me know if is good?
George, your answer is in the response just above your question… No! a 1/12th Hp motor will not produce ANY usable power – you may get the voltage up high enough, but there won’t be any current. If you try to put a load on the motor and pull more current it will burn out in no time. You need something around ONE horsepower.
Thanks a lot 4 the info bruce……
Hi Bruce,
Can you tell me if it’s possible to use Wind Turbine Motors with a bike. I try to build a bikepower, it’s seen turbine motor give more volt/rpm but is it a good idea?
and i would like to put at least 4 deep cycles batteries in parallel for normal use; laptop,light,heater.
anyway, is it possible and effecient?
*sorry for my bad english,
thx
It is possible – you need to gear-up the motor to get the required RPMs. Just think of all the “e-bikes” that are available today. They all use an electric motor and battery to power the bike. You would be doing the same thing, but you are using the electric motor and bike to power the battery.
To skip back a few and answer Jeffery’s question, regardless of the blade size the method for using a wind turbine to charge batteries while driving is essentially completely ineffective. Even if you managed to produce a 100% efficient wind turbine that converted all of the power in the airflow to electricity, you would have to put in this extra power from the vehicles engine. Think of it like running with a turbine held up compared to running without one and the drag that you would feel. The extra force that you need to put in to run at the same speed is equal to the power produced by the turbine (if 100% eff.) This is the same for your van, the engine works harder an ultimately you’d be better of just charging the battery direct from the engine and not encountering the inevitable inefficiencies you will in a real life situation. If this wasn’t true you’d be creating your own energy, no matter how small the amount.
Bruce,
Would a motor with greater than 1 HP be a problem? I have seen a few of appropriate volt to rpm ratios and all are around 2 to 2.5 hp. Is this OK for a DIY wind turbine application?
Alan
You’ll need large blades to turn the permanent magnet motor (generator), but you’ll also get more output… just make sure it’s PMG.
Hello Bruce, I am looking to try and do one of these and after reading through the guides and such I think I finally found a motor that will suit my needs. But before I spent the money on it, I figured I would ask your advice first.
Specs:
.75(3/4) HP
24 VDC
200 RPM
33 amp
shaft is 2″ long
Any advice is much appreciated.
That sounds like a good PMG. The motor tends to be the most expensive part these days. If you aren’t careful you can spend as much for a motor as a complete commercial wind turbine would cost…
Yeah, this one is gonna run me about $125 but its worth it in my opinion. i just hope I am successful in being able to build this properly. This is my first venture into a project of this complexity, so it could be interesting.
I was wondering if a dryer motor would work. They seem to be priced lower, but the hp is generally low as well.
I was thinking 1/3 hp would be low, I was thinking of making a small wind system to charge a 12 V power source.
but I am able to find motors with 1/3 hp, 1650 rpm, 120 – 170 V, 5.3 amps for about 30 USD.
Just wondering what I was missing
A dryer motor is no good (induction motor). You need a motor that has permanent magnets.
ok thanks.
I now got a treadmill for free and took the motor out of it. it is 90/115 Volts, 1 hp. I can’t read anything else on it but it is perm magnet dc. I tried to look it up and found some info saying it might be 4000/4500 rpm. this is a 44.4 rpm/volt ratio. I have been told to aim for 25, so this seems high. I am doing this as a sort of project, and I would like to see if I could power a couple spotlights for horseshoes or just porch lights or something. I was wondering if this would be possible with a motor like this. I guess my main concern is that I don’t think i could charge a 12 V, and my knowledge of the electronics and battery’s is limited, so I don’t know how options with 12 v batterys differ from my options with 6 v
Sounds like you will need some gearing to get a reasonable voltage. At the bottom of this page:
http://greenterrafirma.com/DIY_Wind_Turbine.html
is a 5 minute video showing a very simple gearing setup….
I was considering that and running two windmills if I came across a similar motor. What kind of permitting issues will I run into if running off grid, and is tying into a grid a reasonable option for small systems like this.
if there is a certain amount of energy available from the wind hitting the blades, wouldn’t gearing the turbine up just lose some of that energy through friction. I noticed in that video he used 6 blades, was this to compensate for that loss?
I want to thank you in general for your help. I appreciate it.
Permitting – the only thing I can think of would be related to the tower and how high it is… You will never be allowed to connect a homemade wind turbine to the grid, besides, it produces almost no power….
To connect to the grid, you’ll likely need all kinds of expensive equipment – approved inverters, disconnect panels, fusing, extra meters – all of this equipment would cost more money than your DIY wind turbine would ever make in your lifetime.
Yes, there is only so much energy in the wind – but it varies greatly with the windspeed (cubed). The more blades you have the SLOWER the blades turn, but the more torch (power/push) you have. In the video, he found that with 3 blades he didn’t have enough power/torch to start the blades moving. Once he had 6 blades, the wind blowing on all 6 blades, gave him enough PUSH to turn the motor over. However, at a set wind speed (say 30mph for example) the 6 blades will turn slower (fewer RPM) than a wind turbine with 3 blades…. But again, if your system won’t even start with 3 blades, then you are not producing any power at all.
Bruce.. I don’t really see anything on variable speed PM motors. If they don’t state that they are geared are they a viable unit? In my case the RPM/VOLTS =< 15 when doing the math on a 1 1/2 HP unit. I live on a mountain ridge southwest of Denver and we get winds most of the time and some gusts of even 70 MPH or better. Strong enough sometimes to move a heavy grill.
Ed, unfortunately there is no rule regarding geared or not…. you’d need to find the exact make and model and then confirm with the manufacturer. With those wind speeds, you’ll need to make the wind turbine “heavy duty”. Wood blades would be better than PVC, which tend to warp at high speeds – and shatter if they touch the pole.
Hi, We have just bought a 72v Ametek wind turbine low wind motor to put togeather a wind turbine. I have tried several time to get the amps this motor is capable of and the people we bought it from (Off Ebay) will not email me back. Can anyone help me with finding out how many amps this motor is capale of producing? We have a 10 blade 60″ propeller coming in a couple of days and need to get a charger for it. Sure hope some one can help us out. Thanks
Hi Bruce,
We are planning to construct a HAWT for university project. I saw on ebay 1/2 HP motor with 90vdc and 5 amps. According to your previous posts, such kind of motor should work, isn’t it?
Thank you very much for your help
Forgot to add that it is 1725 rpms
Thank you
You should be able to get 1 VDC for every 19rpm. Thus at 400rpm you could get 21 VDC out of this motor. Of course it needs to be a permanent magnet motor.
I found this permanent magnetic generator on ebay but can not find any other information on the generator. How does this generator stack up, GreenergyStar WindZilla 12V DC Permanent Magnet Motor Generator
Thank you
From the graph on ebay, it looks like this motor produces about 45v at 2000rpm. You need approx 15vdc to 16vdc to charge a 12v battery bank and thus you would need about 680rpm for this to work. A homemade wind turbine won’t get to 680rpm very often and therefore you should expect to gear-up this motor.
It also seems very expensive for a DIY project.
Thank You bruce for your response, where would you recommend finding a decent generator at a good price..
Or is it just pay attention to the RPM and VDC
Great info!
Thanks so much. Why is it so hard to find a motor with the right specs? Doesn’t any other manufacturer, other than Ametek, make motors suitable for a wind turbine?
Regards,
Hello, hello? Anybody home?
We need help with finding an appropriate motor, as seen from the last two posts. How about letting us know what the Ametek motors, that are suitable, were made for in the first place. That alone is a good clue for us to find another manufacturer. Thank you.
Hello Bruce,
Yes, the Ametek PM motor is virtually gone now and I’m not sure what their original target product was. Large PM motors are used in various devices such as treadmills, electric vehicles, motorized wheelchairs, and scooters to name a few. As mentioned below, look at the rated RPM – lower is better, and VDC – higher is better. You need to produce at least 1VDC for every 25 RPM for a DIY wind turbine. Producing 1VDC at a lower RPM speed is even better. And try to find a motor rated at least half a horespower or you won’t get any amps out of it. Finding a motor is the hardest part of building the wind turbine!
Thanks! I will let you know the results of my search.
Just want to know how many watts you would get out of a 1 hp treadmill motor when used as a generator as well as from a 2.5 hp motor. I know these are very low speed motors. If a 1hp motor takes 750 watts to run will it also generate the same amount. ???
Let’s say that the motor consumes 750 watts. Then at most it could produce 750 watts. If it produces that power at 1000 rpm and your average rpm of your wind turbine was 300 rpm you could get around 200 watts out. Then you need to run that thru the electronics – diode, controller, etc. Realistically, you’re looking at about 150 watts in a strong wind with this made up example.
I have a small DC PM motor that puts out approx. 20V @500RPM but has very little amperage at that RPM (less than .1 amp). So even if you have the proper voltage it still takes amperage to charge a battery,is this correct?
Bruce–
I recently acquired an Ametek motor that I can’t find any data on.
On the case it says it’s 38 volts and 12 amps
The part number is 291197F6 –which I can’t find anywhere.
It appears to be a low RPM motor, as I ran it on DC at 12, 24, 30, and 36 volts using a series of 6 and 12 volt lead acid batteries — and I would guess the top RPM at 36 volts was no more than 1000. (I had a 1750 rpm AC motor running along side for referance –both had a small stripe painted on the shaft for visual RPM referance).
I’d like to use this for a wind generator project –do you have any info on this motor ??
Thanks in advance
There are a few versions of the Ametek 38 out there… I don’t have any confirmed specs for them however. We like to see 1 VDC generated for every 25 rpm. Thus at 400 rpm you’d produce roughly 16VDC – enough to charge a 12v battery string. You’d need closer to 450 rpm given the rough estimates you’ve come up with. With a DIY wind turbine, you may only get 4450rpm on very windy days. You could try to gear it up a bit though.
Correct – there are a number of very small motors – used for toy cars, etc, that consume almost no power and therefore with generate almost no power. You need a big, heavy motor – look for something with at least a half horsepower.
Hi Bruce
Fingers crossed you still check this page!
I’ve been searching for a suitable motor for wind turbine generation, and came across this one. Would it be suitable for a small wind turbine generation?
Torque: 60 N*cm
12V DC
120RPM
Diameter: 25mm
Length [excluding shaft]: 59mm
Shaft length: 11mm
Total length: 70mm
Shaft diameter: 4mm
Weight: 92g
It seems from this, that the RPM/V ratio is 10RPM per Volt, within the numbers you suggested.
What wattage would i be able to get, at a maximum from this motor?
Also, I cannot find info on the amperage of the motor, how can i figure this out?
Thanks in advance!
Ollie
Ollie, this is a “toy” motor – a motor for a small toy such as a little race car on a toy race track. The shaft is 4mm= an eighth of an inch wide. It weighs 92g=0.2 pounds.
You want something that has at least a 1/2 hp and weighs close to 10 pounds.It MUST have a permanent magnet (PMG).
Hi Bruce
thought it was too good to be true – thanks for the verification. I’m finding it really really hard to find anything suitable. Can you suggest any sources/places of sourcing?
Cheers
Ollie
Also – I have found a supplier of DC motors, who can supply them in this range –
‘High Efficiency Permanent Magnet Designs
1/4 HP – 4HP, up to 5000 RPM, 12-72 VDC’
Which specifications would be ideal for a small wind turbine? It will be about bicycle wheel size, with 3/4 PVC 4-6ft blades. Thanks!
Ollie
TLG Wind Power Products was the original producer of the Ametek Motor power output tables. You can find a link to their site here: http://greenterrafirma.com/permanent-magnet-motors.html They now produce PMG specifically for DIY wind turbines.
I’d look for something around 0.5HP with low RPMs. Price is usually an issue when purchasing a new motor. You can end up paying more for a single new motor, than a whole wind turbine kit might cost. The people putting the kits together are getting a huge volume discount on the motor they purchase. (and you know the blades will be balanced – do it yourself blades take lots of time to get them balance so they don’t vibrate in the wind)
Thanks for the heads up about the TLG website. Good to know there is a solid motor that I can buy if I need to. Unfortunately, it is a bit out of my price range at the moment until I have played around with cheaper builds yet.
I’m going to attempt to source at motor at a much cheaper price, in the range you mentioned, to build a cheap DIY system, until I have the warranted experience to build a more pricey system.
I’ll keep it all in mind, and probably ask again for advice on a specific motor before i buy (if thats no trouble for you)
Thanks!
Ollie
Thanks for clear info on DC motors. It feels like navigating a jungle finding reliable companies that sell DM Motors producing 12 volts at low RPMs. (If I’ve understood Bruce’s article correctly the “low RPMs” factor is crucial for feasible energy production).
Companies who make DC motors are either not responding to my enquiries, or not providing the crucial information needed before purchase.
For example, a company called Hi~iQ Telecom Ltd on Ebay are selling a 12 VDC DC Motor that appears appropriate.
However, when you look carefully at their graph data the crucial max RPM figure and RPMs that will produce 1 volt appear to be missing.
The company just claim this 12 VDC Motor reaches “12V at 540 RPM” – but that does not mean anything to me, since I do not know if “540″ RPM is a normal RPM in regular wind conditions, or an RPM the motor will achieve during high-speed winds.
I’m beginning to wonder if it would be wiser to build my own DC motor. What do contributors think? Should I attempt this?
I’ve worked as a technician for many years, but I’ll be the first to admit building reliable electric motors that will do this job is not my area of expertise.
I’m also wondering if contributors know of any reliable companies or sellers that do provide the correct type of DC Motor for wind turbines- and do answer buyer questions regarding the crucial RPM factor in good time? Any feedback welcomed.
Kind Regards, OldSchoolTech