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
Similar Posts:
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….