Re: Removing impedance protection from MOEPED #3

From: Dimitrios Tzortzakakis (dimtzortihatespam_at_nospamotenet.gr)
Date: 12/20/04 

Date: Mon, 20 Dec 2004 14:52:48 +0200

There are not too many turns in it, in reality (despite theory) an
asynchronous motor cannot be a generator.Sorry to be the messenger of bad
news, but that's it.That's a reason why (I think so) wind-generators coupled
to the grid in fact work as motors, dissipating power than producing it as
generators.To produce ac, you need a *synchronous generator*, found
everywhere from small heads (650 W) to the largest one, 2000 MVA, operated
in a nuclear power station.Or, a dc *generator* (not motor).Either with
shunt, series or compound excitation.Usually it's shunt. 

--
Tzortzakakis Dimitriïs
major in electrical engineering, freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
Ï "DGoncz 22044-0394" <DGoncz@aol.com> Ýãñáøå óôï ìÞíõìá
news:Gkdxd.4212$Qk5.104@lakeread04...
> MOEPED #3 is mechanically stable and more than half of the onboard 110 VAC
> systems are on line.
>
> MOEPED stands for MObile Experimental Physics Educational Demonstrator.
It's
> my project for one repeated credit at the community college Seminar and
> Project in physics, PHY 298, with Dr. Majewski. It is a 2004 Lightning
Cycle
> Dynamics (www.lightningbikes.com) Thunderbolt recumbent, their base
7-speed
> model, with several transmission changes.
>
> First, there is the tandem crankset. Providing a 51 tooth cog on the left
> side lets me drive a modified Surplus Center (www.surpluscenter.com)
10-1134
> "impedance protected" (stall proof) ceiling fan motor with bike chain at
> about its design rpm, or drive the pedals from the motor. Driving the
pedals
> from the motor helps debug the wide-range 24-35-51 / 11-34 gearing.
Driving
> the motor from the pedals should produce AC when patched correctly but it
> doesn't and that is what this post is about. Pics are at
> ftp://users.aol.com/DGoncz/Bicycle/ACMotorGenerator/
>
> Second, the rear hub has been replaced and relaced with an 8 speed disc
hub,
> 7 cogs, a spacer, and a Big Cheese spider to carry chain rings on the left
> side. A 48 tooth cog drives an Ametek servo motor from C&H sales
> (www.candhsales.com) rated 30 VDC, 12 A stall, 900 rpm, which drives a
Radio
> Shack inverter (www.radioshack.com) rated 140 W, 10-15 VDC, 2.4 W idle.
The
> pinion is 8 teeth, comes from Northern Hydraulic, who I think are at
> (www.northerntool.com) and has been thinned to 2 mm and chamfered. The
motor
> mount is made from plastic drain pipe, hangs from the seat stay clamps,
and
> is tensioned from the seat brace. An aluminum motor mount is in the works.
>
> The bike has been fitted with an ESGE dual leg kick stand, *backwards*.
> Lighning has accepted this recommendation for their customer tip file. I
> have not seen it in print. The bike stands on its own, and a bit of wood
> underneath with two pocket holes captures the legs when you want to pedal
> and prevents spreading of the kickstand legs. Two extra long spokes will
soo
> n be fitted to the stand legs to snag the chain stays with the spoke
heads,
> and wing nuts will tighten the spokes to lock the stand, allowing seated
> pedaling. It will take five minutes to set up once parked.
>
> To proof the power generating ability of the system I plugged the motor
into
> the inverter and went for a ride. As expected, it was a dynamic brake, but
> nothing blew up. The system could generate say 20 watts all night long
while
> riding and you'd hardly notice it. I've run a fluorescent lamp from the
> inverter. I could run my laptop from it but I don't have a padded case
yet.
>
> My question to the readers of alt.engineering.electrical,
> rec.crafts.metalworking, sci.electronics.design, and
sci.electronics.repair
> is:
>
> Given this is an impedance protected ceiling fan motor with many turns of
> fine wire, and I have invested four years of effort, and the system is
> stable, is it now time to rewind the stator with fewer turns of thicker
wire
> to optimize generator function, as it is not likely that this motor will
> ever be stalled, or should I continue to try various cap combinations,
> driving the AC motor/generator from the DC motor in reverse, or should I
run
> a sweep to find out what is going on and *compute* an optimized cap? I'm
> leaning toward rewinding the stator. It seems like an idiot proof motor
> would make a lousy generator.
>
> The motor run cap is currently 5 microfarads. The self-excitation cap is
> currently 30 microfarads. Currently the motor runs right as a motor, but
> only generates 0.1 VAC at best speed when patched as a generator, even
when
> I "whack" it with DC while cranking as described in Lindsay's "Alternator
> Secrets". I suspect there's just too many turns of wire in there. I have
an
> audio amp and can download Daqarta again for a sweep. I have a Tek 541
scope
> with CA plug in. Soon all these and the bike will be under one roof.
>
> Yours,
>
> Doug Goncz
> Replikon Research
> Seven Corners, VA 22044-0394
>
>

Relevant Pages

  • Re: Split Phase Motor/Generator
    ... > I have assembled the motor to my bicycle and it runs the cranks just fine. ... > torque, allowing the motor to act as a generator. ... This generator will power the inverter, ... Rider power will be transormed by the generator into AC ...
    (sci.electronics.design)
  • Re: Inpedance Protection of Ceiling Fan Motor
    ... >>If you only need 8W then a good bicycle generator plus inverter might ... > stall as a motor. ... Bicycle shock troops? ...
    (sci.electronics.design)
  • Re: Inpedance Protection of Ceiling Fan Motor
    ... is, I want to be able pull over while riding, extend the ESGE dual leg ... stall as a motor. ... >these in a river-based generator and they run day and night, ... derailers by moving the pedals at a constant, ...
    (sci.electronics.design)
  • Removing impedance protection from MOEPED #3
    ... or drive the pedals from the motor. ... and prevents spreading of the kickstand legs. ... ever be stalled, or should I continue to try various cap combinations, ... would make a lousy generator. ...
    (sci.electronics.repair)
  • Removing impedance protection from MOEPED #3
    ... or drive the pedals from the motor. ... and prevents spreading of the kickstand legs. ... ever be stalled, or should I continue to try various cap combinations, ... would make a lousy generator. ...
    (sci.electronics.design)