How powerful of a motor do you need to run an alternator? Answered

From questions I have read and step by step’s I have read a question came to my mind. How powerful of a motor do you need to run an alternator? I checked the Delco Remy alternator series from 10SI in 37 Amps, to the 40SI durable brushless model, in 240, 275, and 300 Amps. All their performance charts show rpm’s at the alternator not the motor. The pulley on the crankshaft is considerably larger than the pulley on the alternator, giving you more rpm’s at the alternator than at the motor. All their performance charts show rpm’s from 1200 to 8000 rpm’s. All their performance charts show at 3000 rpm’s you get 13/16ths of max power. The last 5000 rpm’s only gaining 3/16ths of power. The thing is none of the performance charts say the horsepower to drive the alternator. I decided to approach the problem from a different direction Typical alternator efficiencies are in the 54%-60% range. Brushless alternator efficiencies are in the 60% 70% range. A typical 12v 60 Amp alternator produces 720 watts at 55% efficiency. It needs just 1310 watts to drive it or a little under two horsepower at 1492 watts. This does not account for mechanical efficiency of connecting the alternator to the motor. With this in mind a three horsepower motor should drive a 12v 60 Amp alternator. This is just an educated guess but I would like a horsepower chart. 720 watts would do well at charging a battery bank while you sleep; however I could not run my microwave and charge batteries at the same time.

Question by Josehf Murchison   |  last reply



Why do people prefer the predator engine over others?

I wanted to get a Duramax engine for my go-cart seeing it has 16 -18 horsepower yet every video I watch on youtube they have a predator engine with 6.5 horsepower, which is better?

Question by RubenG81   |  last reply


How much thrust usally does a 9 inch fan give out ? Answered

How much thrust does a 9 inch fan give out? Also how about a 1.5 feet R/C helicopter. How much horsepower is required to lift a human. How much thrust. If you had a 100lb man and had 101lb thrust how far up in the air would the 100lb person go. Sorry really dont want to do the calculations right now.

Question by planetroverrobo   |  last reply


Universal motor

After disassembling a hedge trimmer I have obtained a universal motor (meaning it can run on either ac or dc) It has a power rating of 400W, and a label indicates that it has 1/2 horsepower. Does anyone have any ideas as to what to do with it? it's fairly small (15cm X 5cm X 5cm) and in reasonable condition. Thank you for any responses.

Topic by csharpdeveloper   |  last reply


variable frequency drive construction?

Hello i am working on a go kart but instead it will be powered by a 1/3 horsepower split phase AC motor. it operates off 768 watts and i am curious in using a Microcontroller and a high power H bridge to control it. can anyone help me or give me an idea on how to step up 12v dc into 120v dc and then using the H bridge to generate the frequency and also where to find some NPN transistors that can handle it and how to possibly reverse the direction of the motor?

Question by luig   |  last reply


I am switching from SLA to NiCad on my e bike. I have a 48v controller, what options do I have? Thanks for having me!

Do I have to have exactly 48v of batts or can I use maybe 2 18v nicads? I was a music major, so when you guys and gals start using formulas to come up with amps, voltage. horsepower it blows me away.  Any information on where I could learn the basics would be appreciated.

Question by jackdullboy   |  last reply


Help with wiring

I have disassembled an old vacuum cleaner that runs on 240v/5amps/1200w. I wanted to obtain the electric motor that should perform at 1.5 horsepower. As I was taking it apart I forgot how the switch leads were originally configured. I want to give the motor a test run but I don't want to hit the fuse in my house so I was hoping someone can help me plug the switch in the normal configuration. What order do the brown and blue plugs (that comes from wall plug) fit into the switch? And what order do the blue plugs (goes to motor) fit into the switch? A silly question really but I am new to working with electronics.

Topic by Tyoon   |  last reply


Idea: piPod, piPad, piPhone

Okay, so here's the idea.  Inexpensive RaspberryPi computers have lots of horsepower, an SD slot, audio jack, and place to hook a screen...  Why not kludge together your own iPod or even iPad.  Also, slap on one of MIT's cell modules and you've got the iPhone. Sure it might look funky and may even cost more than the real deal, but half the coolness is just to say you did it yourself! (P.S.  Since I just coined the terms piPod, piPhone, and piPad, you've got to send me one if you make it work!  Please?  Pretty please?  Maybe??)

Topic by PS118   |  last reply


how do i make a 12V electrical motor stronger? Answered

Im trying to make a batteryless die, and im now in the process of wrapping a plastic tube with copper wire, but after 200 times around, ive had enough (i need 2500!!!) so i decided to use a motor to do the hard work (wich would be faster also :D) so, i made a motor thats steadier, added a switch and a 9V battery, but it went to fast, with not enough power, resulting in ALOT of wire used, wich wasnt wrapped tight enough against the tube. so, i tried holding it with my hand to slow it down, but again, its not strong enough to pull the wire on strong enough. so, in a nutshell i need the motor stronger, not faster. like adding more horsepower instead of kilometers/hour...

Question by godofal   |  last reply


Treadmill Motor Control

I have a Horizon T101-04 treadmill that has a control problem. The motor is definitely good. I suspect that the motor control board is good, and the control panel board is bad. The control will not reset or go into diagnostic mode. I want to replace either the control panel board or the entire control system. The motor is 90V DC. For amperage, the motor label says "19A S6 25%" which has no meaning that I understand, other than perhaps that the maximum amperage is 19. The label says "APMS" rather than "AMPS", and I wonder if the "S6" is supposed to be "SC" for "stall current." All of the characters on the label are very legible. To replace the entire set of controls, I can use an industrial DC motor control, but how much horsepower does the control actually need to be able to provide? I don't think that the one on the treadmill actually provides 19A, and is probably close to 1 HP or so in its capability.  To replace the control panel with something else and keep the existing motor control, what do I need? Do I need some type of complex driver circuit? Does it need feed back from tach sensor to do a good job of keeping the speed steady?  If it will work well, I want a simple control set up like a KB Electronics KBMD-240D to which I will add a safety cut-off switch with a lanyard.

Topic by Ineedacircuit   |  last reply


Robot Pegasus design possible? Answered

Ok, so I have another idea that will most likely never get anywhere due to my lack of funds/it not being possible.           What if I made a magnetic track somewhat like a maglev and had a robotic pegasus with electromagnets in its feet. It would also be an ornithopter to get it farther than a few inches off the ground. I would have the magnetic track to have it hover a few inches off the ground for about a minute before and after takeoff to make it less likely to crash on landing and give a minute to text the mayor to not worry about any upcoming pegasus sightings above or around town before taking off.           What kind of horsepower engine would I need to power the wings enough to get sufficient lift (at least 15-20 feet)? And would the electromagnet buffer before landing be significant enough to at least lessen the impact so it doesn't maim/kill you if you crash?           The electromagnets don't seem to me like they would work, but it would still be fun just to hover it to show it off without flying up 20-30 feet and worry about falling. Also, would it make it too heavy to fly if I put in an extra motor to make it walk/run so it doesn't have to be flying to move? I don't really expect this to be within my budget, but it would still be cool.

Question by ALogan97   |  last reply