## Re: Three Phase Motor as Alternator/ Latest Developements

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• ... alternator. The ... the direct ... Is this ... whatever the ... Sorry Dave, cant help you much here. Years ago I tried running a 3 phase induction motor
Message 1 of 7 , Mar 7, 2003
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--- In teslafy@yahoogroups.com, "David Thomson" <dave@v...> wrote:
> I have a three phase, 400 Hz motor I'm hoping to use as an
alternator. The
> three hot wires appear to be in delta formation. When I measure
the direct
> AC voltage between the hot leads I get 2 volts between each pair.
Is this
> correct? Am I wrong in thinking there would be 120 volts (or
whatever the
> motor rating is for the rpm I'm running?)
>
> Dave
Sorry Dave, cant help you much here. Years ago I tried running a 3
phase induction motor backwards as a generator, but I did not have
any success. This was clear back around 1990, and I really didnt
know much back then. It was shortly afterwards that I first made an
AC car alternator modification, since that didnt work. I quickly
burnt that one up by driving it at an ungodly rpm, again back then I
didnt know that the 7 pole faces would give 7 cycles per rotation,
and that model melted the stator insulation off when driving it at a
fast rpm that produced some 833 hz. Lindsays publications of a short
pamphlet called "Alternator Secrets" notes the following on your
problem.
"Induction motors have no physical connection between the the
stationary winding and the squirrel cage rotor. The electricity
flowing in the rotor is created by transformer action because the
magnetic field in the stator winding is revolving at 1800 rpm, while
the rotor is revolving at 1725 rpm. The 75 rpm difference, (4 to 5 %)
causes a current to be induced into the rotor.(This is a 60 hz
example , HDN)
When used as an alternator, the motor must be driven 4 to 5 %
faster than the 1800 rpm synchronius speed, (to obtain the 60 hz as a
motor driven backwards as a generator HDN)
Some motors will begin generating power as soon as they're
driven because there's a small amount of residual magnetism remaining
in the rotor and windings. ( Note: I dispute some of that theory,
because it does not also acknowledge that this also consists of a
parametric generator, and we ought not just hypothesize that is is
working by residual magnetism. The 2 volts you are obtaing is
probably due to the parametric effect of making a changing inductance
over time on the motor windings, by rotation of the ferromagnetic
pieces of the squirrel cage rotor HDN)
If generation doesnt begin by itself, you'll probably have to
hit the windings with a pulse of DC current to get it started. A
switch to a 12 volt battery will probably be adequate, although in
some cases you may need as much as 60 volts to do the job.

Lindsays manual also notes the following; Not all motors will work
properly, ( when reverse driven as a generator, HDN), and we dont
really know why. Fortunately most do.

In other news I have made a electrified pepper seed experiment, where
I will soon post a detailed post about the Rife/ Lakhovksy variation
used to make that experiment. Hers a posting sent to JLN list as a
small introduction;

This might also be relevant;
Human Body Found To
Make Its Own Ozone
http://rense.com/general35/hmn.htm
Makes one wonder if we are ingesting ozonated
water, does this help our immune system? I guess some
Scandinavian countries routinely use ozonation for the
water supplies, vs the US practice of using chlorine.
I think I read some time ago those countries did not
widely employ vaccination programs like the US did in
the 60's, yet they did not have outbreaks of epidemics
that were feared to happen without such a vaccination
program.

experiment was done, but heres the results of a 7 day
pepper seed germination experiment. Two tablespoons of
sweet cherry pepper seeds for each sample were used
for the experiment, and then the ones that appeared to
be sprouting were separated after 7 days.
Electrified samples were given 1/2 hour daily
exposures to high voltage. The highest voltage for
the samples was at the North pole of a 3 inch stack of
SrFe magnets, the arc bar sample was placed
afterwards in series from magnet windings where an arc
was derived after a voltage reduction made by a small
4 inch neon in series.. It been real cold in Ohio
lately, and pepper seeds need good heat to germinate,
so actually these are not good results for 7 days for
the amount of seeds used, which is why I used a large
quantity of seeds for each sample to begin with, to
detect percentage wise a difference in germination
rates: I try to keep the heat down in the house in
the winter, these seeds were kept in a shelf in the
furnace room, which doesnt actually stay that hot
anyways with the thermostat set at 60 degrees.

http://groups.yahoo.com/group/teslafy/files/MED/Dsc00461.jpg

Latest developements;
Today I recieved another sample of ozonated distilled water from the
Ellis water process, and will soon be making conductivity tests on it.

Work on the power factor corrected air core transformer has sort of
digressed into limbo lately. I'm wanting to make a definite
improvement on the existing process before I spend more time
documenting it. To do this I tried putting primaries on both sides of
the secondary. Paradoxically this did not improve the secondary
performance, and the input amperage to primary did not double,
although that might be predicted. The primary was constructed as a
figure 8 Binary resonant Tank circuit, with coils above and below the
secondary high induction coil. The BRS Tank primary did not behave
as the larger twenty 14 gauge coil model does, where the midpoint
path shows a doubling of amperage. Instead the same amperage was
inputed, but each branch also contained the resonant rise of
amperage, making for a doubling of previous output in terms of amp
turns on the primary coils, but not a doubling of input amperage. (
this is not conclusive, I only measured the midpoint pathway, but
previous tests have shown what I am indicating here, the midpoint
amperage is identical to the coil amperage in this instance.) I do
not know why that in some cases the BRS acts as advertised, and some
cases this does not occur. It may have to do with the coils of each
branch necessarily being involved with some sort of mutual
inductance, although that sounds speculative at best, because these
14 gauge coils have been shown to have very little mutual inductance
in comparison to the use of large induction coils. It may also
involve the requirement of making the coils to be finely tuned, which
in this case they were not, they were just given C values known to be
approximately correct. The strategy next will be to reassemble the
figure 8 primary tank, and then to give each of those coils an
independent secondary as a high induction coil. Then each of these
will connected to the same output as before, which is the 20 coil
figer 8 tank. This would be like putting tow output currents in
parallel, where hopefully then that output's amperage will also
double. If this can occur, then we will have the situation of a
doubling of current output. As the situation stands now the current
inputed to the primary, is evidenced as the same current output on 20
coils of the same dimension, which is definitely a good perfomance,
where we have to start thinking that this resembles overunity by I^2R
losses, even after accounting for the resonant rise of amperage on
the primary.

Sincerely HDN
• AC induction motors *can* be used as generators, but it takes some work. You can t just hook the thing up to a load, turn the shaft and expect it to produce
Message 2 of 7 , Mar 7, 2003
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AC induction motors *can* be used as generators, but it takes some work.
You can't just hook the thing up to a load, turn the shaft and expect it
to produce electricity.

The best way is to use a 3-phase DC-to-AC inverter as a motor
controller. These are commonly used to control the speed of large
industrial induction motors by varying both the frequency and the
voltage of the 3-phase AC supplied to the motor.

Remember how an induction motor works. When 3-phase AC power is applied
to the stationary field windings, they set up a rotating magnetic field
within the motor. This rotating field induces a current in the rotor,
which consists of a shorted transformer turn and no external electrical
connections. The magnetic field then produced by the induced current in
the rotor acts on the rotating field to cause the rotor to turn in the
direction of the rotating field.

As the rotor speeds up, it approaches the speed of the stator's rotating
field. This decreases both the frequency and the magnitude of the
current induced in the rotor, decreasing the generated torque. If the
motor is unloaded and is completely frictionless, the rotor will turn at
exactly the same speed as the stator's rotating magnetic field and the
generated torque will be zero.

As the load on the motor is increased, the rotor speed will drop below
the stator field speed, increasing the current induced in the rotor and
increasing torque to compensate. This difference in speed is called
"slip". When operated as a motor, the slip is always such that the rotor
turns more slowly than the stator's magnetic field.

But if you apply an external torque to the motor, the slip will go the
other way. Now the rotor turns faster than the stator's rotating
magnetic field and power flows the other way. The unit has become a
generator. With the inverter I described earlier, DC power will flow out
of the inverter towards the source (which is now of course a load.)

This is exactly how the propulsion system in my GM EV1 electric car does
regenerative braking. It has a 3-phase AC induction motor driven by a
3-phase inverter powered by a NiMH battery. Hit the accelerator and the
car speeds up, with the motor acting as a motor. Let off the accelerator
and the motor becomes a generator; energy starts to flow back from the
car into the battery.

There was an article in Home Power magazine a while ago showing how to
use an AC induction motor as a generator in a small hydroelectric plant.
They don't keep their back issues online, though, so you might have to
ask around or purchase a back copy.

--Phil
• Hi Phil, Bert Hickman sent me a link to an article that describes how to convert a 3 phase motor to an alternator.
Message 3 of 7 , Mar 7, 2003
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Hi Phil,

Bert Hickman sent me a link to an article that describes how to convert a 3
phase motor to an alternator.
http://www.microhydropower.com/staffpubs/staff4.htm

Thanks for your explanation of how three phase works. Harvey's explanation
also helped me out. I'm getting a clearer picture of how to deal with this.
I think I'll try the DC across a winding technique first. Then if that
doesn't work, I'll see if I can figure out how to put the right capacitance
across the windings to generate the rotating magnetic field. I'm glad, at
least, to know that it is a technical problem and not my 400 Hz motor.

I tried to put a 10A variac on the drive motor and kept blowing the fuses.
Apparently the 1/3 hp single phase takes quite a bit of amperage to get
started. I was hoping that a variable speed on the 3 phase motor might help
nudge the rotating magnetic field into operation.

Dave

-----Original Message-----
From: Phil Karn [mailto:yahoo1@...]
Sent: Friday, March 07, 2003 8:56 PM
To: teslafy@yahoogroups.com
Subject: Re: [teslafy] Re: Three Phase Motor as Alternator/ Latest
Developements

AC induction motors *can* be used as generators, but it takes some work.
You can't just hook the thing up to a load, turn the shaft and expect it
to produce electricity.

The best way is to use a 3-phase DC-to-AC inverter as a motor
controller. These are commonly used to control the speed of large
industrial induction motors by varying both the frequency and the
voltage of the 3-phase AC supplied to the motor.

Remember how an induction motor works. When 3-phase AC power is applied
to the stationary field windings, they set up a rotating magnetic field
within the motor. This rotating field induces a current in the rotor,
which consists of a shorted transformer turn and no external electrical
connections. The magnetic field then produced by the induced current in
the rotor acts on the rotating field to cause the rotor to turn in the
direction of the rotating field.

As the rotor speeds up, it approaches the speed of the stator's rotating
field. This decreases both the frequency and the magnitude of the
current induced in the rotor, decreasing the generated torque. If the
motor is unloaded and is completely frictionless, the rotor will turn at
exactly the same speed as the stator's rotating magnetic field and the
generated torque will be zero.

As the load on the motor is increased, the rotor speed will drop below
the stator field speed, increasing the current induced in the rotor and
increasing torque to compensate. This difference in speed is called
"slip". When operated as a motor, the slip is always such that the rotor
turns more slowly than the stator's magnetic field.

But if you apply an external torque to the motor, the slip will go the
other way. Now the rotor turns faster than the stator's rotating
magnetic field and power flows the other way. The unit has become a
generator. With the inverter I described earlier, DC power will flow out
of the inverter towards the source (which is now of course a load.)

This is exactly how the propulsion system in my GM EV1 electric car does
regenerative braking. It has a 3-phase AC induction motor driven by a
3-phase inverter powered by a NiMH battery. Hit the accelerator and the
car speeds up, with the motor acting as a motor. Let off the accelerator
and the motor becomes a generator; energy starts to flow back from the
car into the battery.

There was an article in Home Power magazine a while ago showing how to
use an AC induction motor as a generator in a small hydroelectric plant.
They don't keep their back issues online, though, so you might have to
ask around or purchase a back copy.

--Phil

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• Hi Phil, I have tried connecting a 12V 150ma power supply to one leg of the windings and it increased the three phase voltage by a half volt. Before I try a
Message 4 of 7 , Mar 13, 2003
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Hi Phil,

I have tried connecting a 12V 150ma power supply to one leg of the windings
and it increased the three phase voltage by a half volt. Before I try a
heavier amperage or higher voltage on the windings I want to try the
capacitor route.

I have measured the inductance of one leg of the winding to be 8.08mH. I
figure a 19uF capacitor would give me close to the 400Hz the motor runs at.
I didn't have a 19uF capacitor, but I do have a 15uF motor starting
capacitor. This would resonate at about 457Hz. When I connected the
capacitor between on pair of windings, the voltage actually dropped. In
fact, the voltage between the capacitor terminals was zero.

Do I need a capacitor between each pair of wires to get the rotating
magnetic field working?

Dave

-----Original Message-----
From: Phil Karn [mailto:yahoo1@...]
Sent: Friday, March 07, 2003 8:56 PM
To: teslafy@yahoogroups.com
Subject: Re: [teslafy] Re: Three Phase Motor as Alternator/ Latest
Developements

AC induction motors *can* be used as generators, but it takes some work.
You can't just hook the thing up to a load, turn the shaft and expect it
to produce electricity.

The best way is to use a 3-phase DC-to-AC inverter as a motor
controller. These are commonly used to control the speed of large
industrial induction motors by varying both the frequency and the
voltage of the 3-phase AC supplied to the motor.

Remember how an induction motor works. When 3-phase AC power is applied
to the stationary field windings, they set up a rotating magnetic field
within the motor. This rotating field induces a current in the rotor,
which consists of a shorted transformer turn and no external electrical
connections. The magnetic field then produced by the induced current in
the rotor acts on the rotating field to cause the rotor to turn in the
direction of the rotating field.

As the rotor speeds up, it approaches the speed of the stator's rotating
field. This decreases both the frequency and the magnitude of the
current induced in the rotor, decreasing the generated torque. If the
motor is unloaded and is completely frictionless, the rotor will turn at
exactly the same speed as the stator's rotating magnetic field and the
generated torque will be zero.

As the load on the motor is increased, the rotor speed will drop below
the stator field speed, increasing the current induced in the rotor and
increasing torque to compensate. This difference in speed is called
"slip". When operated as a motor, the slip is always such that the rotor
turns more slowly than the stator's magnetic field.

But if you apply an external torque to the motor, the slip will go the
other way. Now the rotor turns faster than the stator's rotating
magnetic field and power flows the other way. The unit has become a
generator. With the inverter I described earlier, DC power will flow out
of the inverter towards the source (which is now of course a load.)

This is exactly how the propulsion system in my GM EV1 electric car does
regenerative braking. It has a 3-phase AC induction motor driven by a
3-phase inverter powered by a NiMH battery. Hit the accelerator and the
car speeds up, with the motor acting as a motor. Let off the accelerator
and the motor becomes a generator; energy starts to flow back from the
car into the battery.

There was an article in Home Power magazine a while ago showing how to
use an AC induction motor as a generator in a small hydroelectric plant.
They don't keep their back issues online, though, so you might have to
ask around or purchase a back copy.

--Phil

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teslafy-unsubscribe@yahoogroups.com

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