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Discussion Starter #1
I tried a SEPEX controller with my aircraft generator,
it would not run. The two small terminals were not
the field wiring, only one terminal was. The other
who knows. The other terminal of the field wiring was
terminated at the field's negative terminal.
Therefore, I put a 24vdc battery pack in that wiring
loop. Then I used an ALLTRAX 7245 to power the
armature of the motor. It's working great for me this
way.

When I tried to use the controller to operate the
field and armature at the same time, I didn't have
enough dead stop torque to overcome a pebble in the
road.

I've got some drawings on this on: www.texomaev.com ,
within the link of "Mitsubishi Eclipse Conversion
Project" They may clear up some confusion of how to
use the aircraft generator with a modern controller.



--- Zeke Yewdall <[email protected]> wrote:

> Unless I'm mistaken, standard motor controllers will
> not work very
> well with a shunt or sepex motor (like an aircraft
> generator
> essentially is), unless you use a separate power
> supply for the field.
> I'm not sure exactly what yours is like, but it
> should have four
> terminals on it, not just two like a typical series
> motor. My big GE
> sepex motor has four -- two for the field and two
> for the armature.
>
> The options as I understand them are --
>
> 1) use a controller made for a sepex motor
> http://www.electrofit-zapi.com/hfcontsepex.htm the
> Sem3 for 96 volts
> 400 amps might be useful for you.... These apply
> full field voltage,
> while chopping the armature voltage, then when
> armature voltage
> reaches 100%, they start chopping the field voltage
> to increase the
> RPM's that way. I have been unable to find any
> controllers rated at
> higher than 96 volts 400amps though. And I want
> about 120 to 144
> volts and around 600 amps for mine.
>
> 2) Use a fixed field voltage of much lower than the
> armature voltage,
> and use a conventional chopper controller on the
> armature -- sounds
> like that's working out pretty well for Michael's.
>
> 3) Apply full armature voltage, and full field
> voltage to start with
> (and use a clutch, probably), and then slowly reduce
> field voltage to
> increase motor RPMs. This is what I think I'll do
> with mine to begin
> with -- the previous owner of the motor said it
> worked well for him.
> If it doesn't work out, I'll switch to 2).
>
> Z
>
>
>
> On 7/31/07, Phelps <[email protected]> wrote:
> > Upp sent this to the wrong address last time..
> Better late
> >
> > Roland wrote
> > > > > Motors are inductive loads, where the ampere
> will rise with increase
> > > > > voltage
> > > > >
> > > > > Unlike resistance loads as a heater, where
> if you have a 240 v heater
> > > > > Element at 8 amps, it will become 4 amps at
> 120 v.
> > > > >
> > > > > A motor that it windings are rated for 240 v
> may use 10 amps where A
> > Motor
> > > > > Has its windings rated for 120 V may use 20
> amps for the same hp. But
> > > > > using
> > > > > Different voltages on the same windings
> rated for some other voltage
> > The
> > > > > Ampere may increase as follows:
> > > > >
> > > > > Here is the results of a 180 VDC motor test
> I did using different
> > Voltages
> > > > > At no load:
> > > > >
> > > > > Battery Pack Actual Volts Amperes Rpm
> > > > >
> > > > > 12 12.6 5 634
> > > > > 18 18.9 6 1013
> > > > > 24 25.4 6.2 1390
> > > > > 30 31.8 6.4 1773
> > > > > 36 37.8 6.6 2143
> > > > > 42 44.5 6.8 2521
> > > > > 48 51.2 7.0 2985
> > > > > 54 57.5 7.5 3270
> > > > > 60 63.7 8 3715
> > > > >
> > > > > There is a maximum voltage and ampere rating
> you can go over on a
> > Motor.
> > > > > This is call the Service Factor (SF). If
> 115V motor has a rated SF of
> > 115%
> > > > > And the motor has a ampere rating of 200
> ampere for continuous running
> >
> >
> > > > > then
> > > > >
> > > > > 200A x 1.15 = 230 amps. The 115V motor can
> run on 115V x 1.15 = 132.25
> >
> > V.
> > > > >
> > > > > On the label for the motor, there should be
> a Service Factor which may
> >
> > Say
> > > > > SF 1.25 for a DC motor. I don't why the ADC
> and Warp motors do not
> > Have
> > > > > Motor label that list the specifications of
> the motor.
> > > > >
> > > > > My General Electric motor does. It list the
> DC motor as 165 volts at
> > 175
> > > > > Amps at 32 HP with a SF of 1.25 meaning the
> over voltage can be about
> > 208
> > > > > Volts and the over ampere can be 218 amperes
> continuous.
> > > > >
> > > > > Roland
> >
> > Therefore what I need to know is .
> > If I chooses to go with 72 volts on my 30volt
> rated motor hoping to use less
> >
> > Than half the amps to do the same job .. Will that
> really be what I get??
> > According to the above maybe not..
> >
> > However..
> >
> > Am I missing that some controllers actually
> decrease and control the
> > Actually amps delivered to the motor?
> > As I was told earlier here . They don't change the
> amount of amps .. Just
> > That amount of time that the amps are applied to
> the motor.. Or are some
> > Controllers different in that since.. ..
> > So if I understand what I am herring.. Then also
> if the actually amps are
> > Not changed .. If I open my controller up full to
> achive max speed the
> > Amount of amps will not be decreased and my poor
> motor will die If the amps
> > Raise and double when I raise the volts that I am
> considering to make my car
> >
> > With 72 instead do 30volts..
> >
> > Tanks Mitchell
> >
> >
>
>
 

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Registered
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70 Posts
Discussion Starter #2
Oops, I meant in this sentence:

(The other terminal of the field wiring was terminated
at the field's negative terminal.)

To be:

The other terminal of the field wiring was terminated
at the armature's negative terminal.

Sorry about that.



--- Michael Barkley <[email protected]> wrote:

> I tried a SEPEX controller with my aircraft
> generator,
> it would not run. The two small terminals were not
> the field wiring, only one terminal was. The other
> who knows. The other terminal of the field wiring
> was
> terminated at the field's negative terminal.
> Therefore, I put a 24vdc battery pack in that wiring
> loop. Then I used an ALLTRAX 7245 to power the
> armature of the motor. It's working great for me
> this
> way.
>
> When I tried to use the controller to operate the
> field and armature at the same time, I didn't have
> enough dead stop torque to overcome a pebble in the
> road.
>
> I've got some drawings on this on: www.texomaev.com
> ,
> within the link of "Mitsubishi Eclipse Conversion
> Project" They may clear up some confusion of how to
> use the aircraft generator with a modern controller.
>
>


M. Barkley

www.texomaev.com

http://www.austinev.org/evalbum/1135
 
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