L
Large Filipino
Guest
OOOH friction drive!
Possible generator for hybrid rack/pusher
- Thread starter loquin
- Start date
loquin
Well-Known Member
with a 5/8" drive spindle!
L
Large Filipino
Guest
Duct tape.
cooltoy
Member
Glad to see that you guys have not let this thread die off and am so happy to see that we have an electronics expert on board.
As for the dimmer switch, I only used that as a way of getting feedback but now you seem to be saying that it is possible. What about that other speed control you mentioned yesterday? What would the cost be, do you have any idea? Also, did you think that the small motor that you showed us on E-bay is the right one only because I had mentioned the Dimmer switch? Is a motor as big as the one pictured in that pic from Large Filipino too big?
I will build this once things warm up a bit and hope that "we" work things out as far as plans go.
As for the dimmer switch, I only used that as a way of getting feedback but now you seem to be saying that it is possible. What about that other speed control you mentioned yesterday? What would the cost be, do you have any idea? Also, did you think that the small motor that you showed us on E-bay is the right one only because I had mentioned the Dimmer switch? Is a motor as big as the one pictured in that pic from Large Filipino too big?
I will build this once things warm up a bit and hope that "we" work things out as far as plans go.
S
skyl4rk
Guest
Thanks for the link to the charger, that is really cheap!
Here's how I would use the charger on a trailer:
With an existing 36V hubmotor / lead acid battery system, wind a transformer to drop the 120VAC down to about 45VAC, more or less. Then run it through a bridge rectifier capable of maybe 5 amps or better and add a couple of big capacitors across the + and - to smooth out the pulse DC. Check the final DC output voltage and adjust the number of turns on the transformer so the output DC voltage is at the trickle charge voltage for the battery pack, which is going to be about 40DC (I need to check that).
What will happen when you are starting from a stop (which causes the highest amp load on the battery) is that the generator system will be covering the first couple of volts of voltage drop, and the battery will cover the rest of the voltage drop. At higher speeds when the voltage drop is not as high, the generator will be providing most current and may also be able to charge the battery, although the battery may kick in under acceleration or on hills.
This would be a way to build a true hybrid, in fact a three way hybrid, gas, electric and pedal.
Here's how I would use the charger on a trailer:
With an existing 36V hubmotor / lead acid battery system, wind a transformer to drop the 120VAC down to about 45VAC, more or less. Then run it through a bridge rectifier capable of maybe 5 amps or better and add a couple of big capacitors across the + and - to smooth out the pulse DC. Check the final DC output voltage and adjust the number of turns on the transformer so the output DC voltage is at the trickle charge voltage for the battery pack, which is going to be about 40DC (I need to check that).
What will happen when you are starting from a stop (which causes the highest amp load on the battery) is that the generator system will be covering the first couple of volts of voltage drop, and the battery will cover the rest of the voltage drop. At higher speeds when the voltage drop is not as high, the generator will be providing most current and may also be able to charge the battery, although the battery may kick in under acceleration or on hills.
This would be a way to build a true hybrid, in fact a three way hybrid, gas, electric and pedal.
L
Large Filipino
Guest
It would be cool too if the generator self started according to load,just like on a hybird car.
loquin
Well-Known Member
If you want to go high tech, rectify the 120VAC & Filter it. This creates a +/-170V DC power source. Then, add a high voltage push-pull switcher circuit, the output of which will feed through a small, high frequency step-down transformer, approximately 5:1. Then, rectify and filter this voltage. Use a comparater circuit to compare the output voltage to apx. 43 volts, and use this as feedback to to modulate the width of the switching pulses. This is a classic pulse-width modulation power supply, and is highly efficient - in the 95% efficiency range. In addition, because stepping down a high frequency AC signal is so much more efficient than a 120 hertz waveform, you can use a tiny toroidal transformer, smaller than a hocky puck, meaning that the power supply can be much, much lighter than a 120 volt power supply of equal current rating. (You can also, if you wish, add a secondary lower voltage coil to the main transformer that would use standard regulation circuitry to produce a +12V output)
loquin
Well-Known Member
skyl4rk:
A VFD is pretty expensive. Low-power units, for motors up to a horsepower or so, were in the 200-300 dollar range the last time I bought any, about 10 years ago. Plus, the motors themselves have to be rated to be used at low frequencies, (and therefore, lower speeds, and less cooling) and are more expensive also. Your standard AC motor won't cut it. (Edit: here's a link to fractional HP "off brand" VFDs - a .5 HP unit is $189)
That other motor, from EBay could also be used as a DC generator, if you wanted to hook it up to a small gas engine. Or, it could be used to drive the bike. It needs 120 VDC though to develop full power though, which could be supplied through a lamp dimmer/rectifier circuit, as I mentioned above.
However, in order to be a true hybrid, you would need 120 volts worth of batteries to push it to it's maximum output, plus a different control circuit. Probably a control circuit based on high speed switching and pulse width modulation, similar to what I described earlier, if you want to wanted to remain fairly efficient.
cooltoy: That'sDax also has a background in Electronic Engineering. There are probably others here as well
A VFD is pretty expensive. Low-power units, for motors up to a horsepower or so, were in the 200-300 dollar range the last time I bought any, about 10 years ago. Plus, the motors themselves have to be rated to be used at low frequencies, (and therefore, lower speeds, and less cooling) and are more expensive also. Your standard AC motor won't cut it. (Edit: here's a link to fractional HP "off brand" VFDs - a .5 HP unit is $189)
That other motor, from EBay could also be used as a DC generator, if you wanted to hook it up to a small gas engine. Or, it could be used to drive the bike. It needs 120 VDC though to develop full power though, which could be supplied through a lamp dimmer/rectifier circuit, as I mentioned above.
However, in order to be a true hybrid, you would need 120 volts worth of batteries to push it to it's maximum output, plus a different control circuit. Probably a control circuit based on high speed switching and pulse width modulation, similar to what I described earlier, if you want to wanted to remain fairly efficient.
cooltoy: That'sDax also has a background in Electronic Engineering. There are probably others here as well
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L
Large Filipino
Guest
I need to take a nap now. That's so much to absorb.
Imagine someone actually figuring this all out.
Imagine the wealth yet to be aquired.
I would buy one,just for the cool factor and for the telling the roadie on the bike trail how your bike is legal.
Imagine someone actually figuring this all out.
Imagine the wealth yet to be aquired.
I would buy one,just for the cool factor and for the telling the roadie on the bike trail how your bike is legal.
S
skyl4rk
Guest
Do you know if this is how hybrid car systems work? I have been trying to find information on hybrid systems and have not found much.
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