# [EVDL] Alternator with Transformers?



## EVDL List (Jul 27, 2007)

Mike,

You will have to find a transformer for the specific frequency
of the alternator. Using a 60hz one on any other frequency will be
catastrophic. It will melt. I was googling rewiring the alternator for
high voltage and found this site that sells a 115V or 230V generator. 

http://www.tradekey.com/product_view/id/367955.htm

Jody 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Mike Chancey
Sent: Tuesday, October 16, 2007 7:33
To: [email protected]
Subject: [EVDL] Alternator with Transformers?

I have had a weird idea nibbling around at the back of my mind, and I
was wondering if anyone could help me decide if it is worth
investigating. I have a pusher trailer based on a Honda Civic I
occasionally use with my EV conversion. While it pushes well and has
proven handy for taking the EV to EVents outside my normal range, it
doesn't include any method for charging the EV while pushing. In the
past the idea of having an alternator rewound to provide high voltage at
low current has been suggested, but so far I have been unable to find
anyone who can do that. I tried running a small inverter to power my
home built 120 VAC charger on the Civic, but when the battery voltage on
the EV would drop during acceleration, the inverter would overload and
shut down. I was going to try installing a PowerMite 120 VAC generator
driven by a belt off the engine, but there simply isn't enough room.

Here is my strange idea. Since an alternator really is generating
three-phase AC before rectification, could a second one be added to the
engine, then the three AC phases be brought out of the alternator 
and fed to three transformers? Since I am trying to charge a 156 
Volt pack, what if one used three 120 VAC to say 12 Volt transformers,
and fed the AC from the alternator in to the secondary so they stepped
up the voltage instead of stepping it down? I assume since the
alternator is only 60 Amps, each transformer would only require roughly
a 20 Amp secondary. The output of each of the three transformers would
then be rectified and combined to proved high voltage DC to the EV. The
original voltage regulator would be tweaked by adding a variable
resistor and probably a zener to hold the alternator output voltage to
make the stepped up output match the pack voltage.

So, is any of this possible? Can 60 cycle conventional transformers be
back fed the odd frequency from a car alternator? I realize after all
this I would be lucky to get more than about 6 or 8 Amps output, but
that is more than I have now.

Thanks,

Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org Join the EV List at:
http://www.madkatz.com/ev/evlist.html

In medio stat virtus - Virtue is in the moderate, not the extreme
position. (Horace) 

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## EVDL List (Jul 27, 2007)

I had another idea - permanent magnet treadmill motors can become
generators. I bought a 130V treadmill motor for use in my EV to drive
the power steering pump. It said on the package that it would generate
DC if you spin it. I have yet to try it but it is definitely small
enough to fit below the hood. It might only make 5 or 6 amps but at
least it will charge the pack. 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Dewey, Jody R ATC COMNAVAIRLANT, N422G5G
Sent: Tuesday, October 16, 2007 10:09
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Alternator with Transformers?

Mike,

You will have to find a transformer for the specific frequency
of the alternator. Using a 60hz one on any other frequency will be
catastrophic. It will melt. I was googling rewiring the alternator for
high voltage and found this site that sells a 115V or 230V generator. 

http://www.tradekey.com/product_view/id/367955.htm

Jody 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Mike Chancey
Sent: Tuesday, October 16, 2007 7:33
To: [email protected]
Subject: [EVDL] Alternator with Transformers?

I have had a weird idea nibbling around at the back of my mind, and I
was wondering if anyone could help me decide if it is worth
investigating. I have a pusher trailer based on a Honda Civic I
occasionally use with my EV conversion. While it pushes well and has
proven handy for taking the EV to EVents outside my normal range, it
doesn't include any method for charging the EV while pushing. In the
past the idea of having an alternator rewound to provide high voltage at
low current has been suggested, but so far I have been unable to find
anyone who can do that. I tried running a small inverter to power my
home built 120 VAC charger on the Civic, but when the battery voltage on
the EV would drop during acceleration, the inverter would overload and
shut down. I was going to try installing a PowerMite 120 VAC generator
driven by a belt off the engine, but there simply isn't enough room.

Here is my strange idea. Since an alternator really is generating
three-phase AC before rectification, could a second one be added to the
engine, then the three AC phases be brought out of the alternator 
and fed to three transformers? Since I am trying to charge a 156 
Volt pack, what if one used three 120 VAC to say 12 Volt transformers,
and fed the AC from the alternator in to the secondary so they stepped
up the voltage instead of stepping it down? I assume since the
alternator is only 60 Amps, each transformer would only require roughly
a 20 Amp secondary. The output of each of the three transformers would
then be rectified and combined to proved high voltage DC to the EV. The
original voltage regulator would be tweaked by adding a variable
resistor and probably a zener to hold the alternator output voltage to
make the stepped up output match the pack voltage.

So, is any of this possible? Can 60 cycle conventional transformers be
back fed the odd frequency from a car alternator? I realize after all
this I would be lucky to get more than about 6 or 8 Amps output, but
that is more than I have now.

Thanks,

Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org Join the EV List at:
http://www.madkatz.com/ev/evlist.html

In medio stat virtus - Virtue is in the moderate, not the extreme
position. (Horace) 

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
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## EVDL List (Jul 27, 2007)

Hello Mike,

You can generate up to 7kw at 110 VDC out of a alternator that is call a 
inverter alternator made by Delco. To convert to 120 VAC 60 hz, it will 
drop down to 6kw. This takes a unit that is specially design for this 
inverter alternator, which is made by Dynamote Inc. They make different 
models from the 6kw down to .5 kw that runs off this inverter alternator, or 
they even have models that are DC-AC inverters that can run directly off a 
battery pack.

This unit can also generate 12 to 14.5 VDC at the same time the 6KW 120 VAC 
60 hz is generated. You can use this unit as a REGEN by connecting to a PFC 
charger that can accept any input voltage of 60 to 240 VAC which has a 12 to 
425 VDC output.

Using this type of REGEN, you will have to isolation contactors between the 
battery pack and controller and battery pack and charger, so you do not get 
any feed back into the motor controller.

The problem is that this 6 kw unit is large, and normally design for 
auxiliary power in utilities vehicles. I am only using a 3 kw unit that has 
a peak of 5 kw.

You have to keep the alternator rpm up to at least to 1200 rpm to first get 
it to come on which is the excitation rpm. That is why engines use a 6 inch 
pulley on damper wheel and a 2.25 inch on the alternator. A engine idling 
at 500 rpm, the alternator is over 1200 rpm.

You will need about a 8 inch diameter pulley for a electric motor drive 
which you still have to keep the motor rpm at about 300 rpm to keep the 
alternator at it excitation rpm.

To keep the motor idling at about 300 rpm, just install another 0-5kw Curtis 
type pot in series with the Curtis accelerator pot and adjust it for the 
motor rpm you need. Use a on dash selector switch which is mark On - Off - 
IDLE to connected the 5k pot in to the circuit. Or you could use a relay 
which could turn on the idle control when the inverter unit is turn on.

Roland


----- Original Message ----- 
From: "Mike Chancey" <[email protected]>
To: <[email protected]>
Sent: Tuesday, October 16, 2007 5:32 AM
Subject: [EVDL] Alternator with Transformers?


> I have had a weird idea nibbling around at the back of my mind, and I
> was wondering if anyone could help me decide if it is worth
> investigating. I have a pusher trailer based on a Honda Civic I
> occasionally use with my EV conversion. While it pushes well and has
> proven handy for taking the EV to EVents outside my normal range, it
> doesn't include any method for charging the EV while pushing. In the
> past the idea of having an alternator rewound to provide high voltage
> at low current has been suggested, but so far I have been unable to
> find anyone who can do that. I tried running a small inverter to
> power my home built 120 VAC charger on the Civic, but when the
> battery voltage on the EV would drop during acceleration, the
> inverter would overload and shut down. I was going to try installing
> a PowerMite 120 VAC generator driven by a belt off the engine, but
> there simply isn't enough room.
>
> Here is my strange idea. Since an alternator really is generating
> three-phase AC before rectification, could a second one be added to
> the engine, then the three AC phases be brought out of the alternator
> and fed to three transformers? Since I am trying to charge a 156
> Volt pack, what if one used three 120 VAC to say 12 Volt
> transformers, and fed the AC from the alternator in to the secondary
> so they stepped up the voltage instead of stepping it down? I assume
> since the alternator is only 60 Amps, each transformer would only
> require roughly a 20 Amp secondary. The output of each of the three
> transformers would then be rectified and combined to proved high
> voltage DC to the EV. The original voltage regulator would be
> tweaked by adding a variable resistor and probably a zener to hold
> the alternator output voltage to make the stepped up output match the
> pack voltage.
>
> So, is any of this possible? Can 60 cycle conventional transformers
> be back fed the odd frequency from a car alternator? I realize after
> all this I would be lucky to get more than about 6 or 8 Amps output,
> but that is more than I have now.
>
> Thanks,
>
> Mike Chancey,
> '88 Civic EV
> Kansas City, Missouri
> EV Photo Album at: http://evalbum.com
> My Electric Car at: http://www.geocities.com/electric_honda
> Mid-America EAA chapter at: http://maeaa.org
> Join the EV List at: http://www.madkatz.com/ev/evlist.html
>
> In medio stat virtus - Virtue is in the moderate, not the extreme
> position. (Horace)
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
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----------



## EVDL List (Jul 27, 2007)

Well you could get two neodymium permanent magnet alternators. These are
unregulated raw power. No excitation needed to get the power from them. Cost
about $200 each. They can output 85v and 150amps reliably each. Wire two of
them in series and you'd have 170 volts and possibly 25kW. Of course they
may overheat. I'd definitely check the temp at that power level. You'd have
to spin them at 9000rpm to maintain this power level though. check graph at
www.windbluepower.com
http://www.windbluepower.com/Wind_Blue_Motor_Hydro_Permanent_Magnet_Alternator_p/dc-500.htm
. 

If you put them together you'd have to add a couple diodes to each to
prevent their installed 150 amp diodes from rupturing. Guess a couple 300
amp diodes would be necessary. 

Problem is if voltage goes too high it might effect the controller
negatively. A large generator could be hauled around I suppose, but that
would require starting from scratch. 

I know you can buy 3000 (6000 watt peak) watt Vector inverters for $200 each
with free shipping. They are huge boxes! Get two of them and some 4/0 cable
and you'd have 6000 watt continuous. 








> Mike Chancey wrote:
> >
> > I have had a weird idea nibbling around at the back of my mind, and I
> > was wondering if anyone could help me decide if it is worth
> ...


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## EVDL List (Jul 27, 2007)

http://www.pcdirect.com/product.asp?promo=pricewatch&PID=1&Sku=PIVE-VEC051GM 
for the inverter , forgot to send the link. 








> Mike Chancey wrote:
> >
> > I have had a weird idea nibbling around at the back of my mind, and I
> > was wondering if anyone could help me decide if it is worth
> ...


----------



## EVDL List (Jul 27, 2007)

From: "Dewey, Jody R
> You will have to find a transformer for the specific frequency
> of the alternator. Using a 60hz one on any other frequency will
> be catastrophic. It will melt.

An alternator's frequency varies with RPM. The relationship is

Frequency (Hz) = RPM x Poles / 120

Alternators are usually belt driven to spin at about 2.5 times the engine RPM, and have 8 to 16 poles. For example, if your engine runs at 600-6000 RPM, and the alternator has 12 poles, then its output frequency varies from 150 to 1500 Hz.

A transformer needs a core suitable for the frequency of operation. The precise frequency isn't important; a 60 Hz transformer works reasonably well from 50-100 Hz (which is why you frequently see 50/60 Hz transformers). You might "get away" with running it at 150 Hz, but it would get hot. At 1500 Hz it would quickly overheat, as Jody said.

The correct transformer for the output of an alternator would be a "high cycle" transformer, rated at a nominal 400 Hz. These are common in aircraft. The good news is that a 400 Hz transformer is about 1/4th the size of an equivalent 60 Hz transformer. The bad news is that since they are built for aircraft, they are outrageously expensive (unless you buy one surplus).

--
"Excellence does not require perfection." -- Henry James
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

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## EVDL List (Jul 27, 2007)

From: Mike Chancey
> ... Since an alternator really is generating three-phase AC before
> rectification... could the three AC phases be brought out of the
> alternator and fed to three transformers?

Yes. An alternator produce roughly 14 vac at 100-2000 Hz. The voltage is set by the field current, and can actually be just about anything from 0-100 vac. The frequency depends on RPM and number of poles (Hz = RPM x poles / 120).

A standard 60 Hz transformer would overheat due to the high frequency. But you can use a 400 Hz "high cycle" transformer or autotransformer. For example:

http://cgi.ebay.com/POWERSTAT-400HZ-VARIABLE-TRANSFORMER-AVIONICS-POWER_W0QQitemZ170155741063QQihZ007QQcategoryZ71390QQcmdZViewItem

Three of these (one per phase) can step up the regulated 14 vac from a stock alternator to 120 vac. This can be rectified (with a 3-phase rectifier). Since these are autotransformers, the output will NOT be isolated from the normal negative output of the alternator.

--
"Excellence does not require perfection." -- Henry James
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

> Evan wrote:
> >On 10/16/07, Mike Chancey <[email protected]> wrote:
> > > I tried running a small inverter to
> > > power my home built 120 VAC charger on the Civic, but when the
> ...


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## EVDL List (Jul 27, 2007)

Alternators are three phase. (I didn't think they had that many poles, I
have had them apart and 12 poles would be 36 coils. 16 would be 48. that
seems high)

Eitherway, I thing you would want a 3phase in single phase out
transformer or just leve the alternator as is and power an old UPS inverter.

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## EVDL List (Jul 27, 2007)

> Jeff Shanab wrote:
> > Alternators are three phase. (I didn't think they had that many
> > poles, I have had them apart and 12 poles would be 36 coils. 16 would
> > be 48. that seems high)
> ...


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