|
| Author |
Message |
vidaliaman
Member
|
# Posted: 4 Oct 2014 04:15pm
Reply
after going through my pole building i found my broken trolling motor, only thing wrong is broken shaft(forgot to pull up while full speed)
12v motor, bought at garage sale for 5 bucks, nice until i broke the shaft, 3 wires going to motor, red and black probably 12 or 10 gauge and a smaller wire(blue), i can take the prop off and hook a drill for turning, do i turn in reverse and hook my volt meter to it to determine how much juice it will create?
how should i determine what kind of power this will generate
once again pardon my ignorance but having a blast figuring this stuff out
|
|
bldginsp
Member
|
# Posted: 4 Oct 2014 04:34pm
Reply
You mean for a water wheel?
It seems to me that maybe you are sort of approaching this backward- I think the thing to do is first come up with some sort of calculation about how much power you can get out of the water stream you have, then find components to match it. Could be your trolling motor is way too small or too large for the power you can get out of the stream.
But I have no idea how you would calculate the power of a water wheel- must be charts or calc formulas for doing so.
Otherwise you are just doing blind experimenting to see what works, which, heh, is fun, and if you are willing to do all the work associated with trial and error you will probably dial in a working system.
|
|
vidaliaman
Member
|
# Posted: 4 Oct 2014 05:02pm
Reply
this is just for education purposes for me, i want to check this motor out with my multimeter, what do i need to do to see what this motor can generate? remember there is a smaller gauge wire(blue) along with the 10 gauge red and black wire,what setting would you use on the multimeter to check out what this motor is capable of? do i spin it backwards?
|
|
FishHog
Member
|
# Posted: 4 Oct 2014 06:40pm
Reply
as far as I know, trolling motors are not much different than most electric motors. They aren't alternators and won't generate electricity running in reverse.
But I could be wrong......I just don't think so.
|
|
toyota_mdt_tech
Member
|
# Posted: 4 Oct 2014 11:37pm - Edited by: toyota_mdt_tech
Reply
Quoting: vidaliaman after going through my pole building i found my broken trolling motor, only thing wrong is broken shaft(forgot to pull up while full speed) 12v motor, bought at garage sale for 5 bucks, nice until i broke the shaft, 3 wires going to motor, red and black probably 12 or 10 gauge and a smaller wire(blue), i can take the prop off and hook a drill for turning, do i turn in reverse and hook my volt meter to it to determine how much juice it will create? how should i determine what kind of power this will generate once again pardon my ignorance but having a blast figuring this stuff out
It will produce current. I suspect its the permanent magnet type, so there is no way to control output. Its going to produce full power and load on it will be heavy. I doubt it would spin enough after the laod is applied. You can throttle it back with a resistor, but its just converting it to heat there, motor will still have the same load. A automobile generator would be a better deal, you can control field current and back it down to reduce the load and get it spinning and charge the batteries slowly.
A motor will generate in only the direction it runs. But good news for a permanent magnet motor, revere polarity, it runs opposite direction. So spin it backwards, red is ground, black in positive. 
|
|
vidaliaman
Member
|
# Posted: 5 Oct 2014 10:02am - Edited by: vidaliaman
Reply
great info, this trolling motor is only for experimental purposes for me to learn more, i am 8 months off building cabin, just want to be prepared with knowledge when the time comes, will experiment through the winter with different motors.
any idea what the smaller blue wire would be for?
what setting should i use on my multimeter to test the output?
|
|
SE Ohio
Member
|
# Posted: 5 Oct 2014 10:45am - Edited by: SE Ohio
Reply
Set meter on DC volts. If you have voltage ranges to chose from, set much higher than 12 volts initially, and you can back off a bit to a lower dc voltage if needed. Take notes of which wire combinations produce results (it should hurt anything just to measure voltages between wires). One can turn DC motor with water or wind. Lots of online plans, some with diy charge control circuits. It's fun to experiment!
|
|
toyota_mdt_tech
Member
|
# Posted: 5 Oct 2014 10:49am
Reply
I have no idea what the blue wire is for, unless there is electronic controls to throttle the motor down, it may be an input to a SCR (silicone rectifier) which behaves like a transistor, but for a much heavier application. I suspect it may be in the motor housing, the blue wire is a signal wire from the controller head and goes to the "gate". But this is all just speculation. But I know those trolling motors do throttle down. In the older models, they just used a long wire wound resistor in the motor shaft and several "fixed" speed settings. Does it have fixed settings for speeds or is it variable? If its variable, I bet its for the SCR.
Here is a good explanation of the Shokley diode or SCR.
http://www.allaboutcircuits.com/vol_3/chpt_7/5.html
|
|
|
bldginsp
Member
|
# Posted: 5 Oct 2014 12:10pm
Reply
Here's a link to a webpage by a guy who has figured out electricity production from water wheels. He's got a calculator to figure watts produced given water head, rate of flow, and wheel diameter, and he discusses the most efficient type of alternator to use for the purpose. A fun read even if you don't plan to put in a wheel:
http://www.waterwheelplace.com/water_wheel_electricity.html
|
|
SE Ohio
Member
|
# Posted: 5 Oct 2014 12:23pm
Reply
Website for wind power, including plans for blades, etc. Some simple but effective blades are made from carefully-cut PVC pipe. As bldginsp said, fun reading even if you don't implement.
http://www.scoraigwind.com/
|
|
vidaliaman
Member
|
# Posted: 5 Oct 2014 02:24pm - Edited by: vidaliaman
Reply
holy cow!!! awesome, thanks
ok setting the meter at 20 dcv it shows between -6.5 to -6.9 using my drill(clockwise) connecting red to red and black to black, spinning clockwise i get 6.5ish when i use my meter red to black and black to red, as the cordless drill weakens slightly it drops to 6.2ish, what would i call the 6.5 number and how would that effect charging 2 12v batteries running 4 LED lights? just looking for ball park thoughts, remember just experimenting
would like someone to walk through the math, thanks
|
|
SE Ohio
Member
|
# Posted: 5 Oct 2014 04:48pm
Reply
May not be enough voltage for a 12 volt battery, but might charge a 6 volt battery. Also, many LED's need 3 volts to light. Could consider a series-parallel string of LED lights directly powered by the now-DC generator no battery, or with 6 volt battery, depending on your water or wind consistency. Might repurpose some solar lawn-lamps with worn-out solar cells? Again, fun to experiment.
(In the same spirit, I recently repurposed some tired solar cells to power a small radio for our porta-potti)
|
|
vidaliaman
Member
|
# Posted: 5 Oct 2014 08:04pm - Edited by: vidaliaman
Reply
thanks ohio, if it reads 6.5 and i have it set on 20 dcv, what do i call the power it creates? is it correct to say this motor produces 6.5 volts? or is it correct to say this motor produces 6.5 amps? or is it correct to say this motor produces 6.5 watts? what is the proper terminology for my multimeter set at 20 dcv and it reads 6.5?
|
|
SE Ohio
Member
|
# Posted: 5 Oct 2014 09:09pm
Reply
You measured 6.5 volts. Not sure how many watts (power) you can generate, which would be volts x amps. LED's don't require much power to light, if that's the direction you want to go.
|
|
Don_P
Member
|
# Posted: 5 Oct 2014 10:14pm
Reply
You have 2 speeds on that drill, and do you have a small corded drill that spins faster? What does varying speed do to the voltage?
Bldginsp, I made that calculator for him, he had all the math posted but didn't know how to write it. I stumbled onto his site looking for the math, I used that to write the calc and sent it to him to post on that page.
|
|
bldginsp
Member
|
# Posted: 5 Oct 2014 10:21pm
Reply
You said you're not an engineer DonP, but you manage to engineer some unique solutions. Good old American know-how. Wish I had a stream for a water wheel.
|
|
vidaliaman
Member
|
# Posted: 6 Oct 2014 08:18am
Reply
my cordless drill runs at roughly 1500 rpms and my corded drill runs at roughly 850 rmps, corded drill produces 4 volts and cordless produces 6.5(drill battery probably not a full charge), lets say i get 6.5 volts from this motor, how long would it take to recharge a 12v battery with 115 amps at 50% depletion?
|
|
SE Ohio
Member
|
# Posted: 6 Oct 2014 05:57pm
Reply
I don't think you'll be able charge a higher voltage than what you are getting from your DC generator. You might charge a 6 volt battery, but not a 12 volter.
|
|
Don_P
Member
|
# Posted: 6 Oct 2014 07:34pm
Reply
It sounds like you'll be in the 2500-3000rpm neighborhood to produce 12+ volts (~14) that would be needed to charge a 12V battery. Time is dependent on the amperage that motor can produce.
|
|
|
