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Inverter efficiency versus motor-generator

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Posted by Narrff on April 13, 2005, 7:18 pm
 


Hello again,

    What are the relative merits of using an inverter versus a
motor-generator, both of them being powered by battery bank?

    For some odd reason, it seems that the motor-generator would be
more efficient, simply due to the fact that there are fewer components
to contribute to the waste.

    Wrong or right, I highly appreciate any input.

    Thanks,
    J.
    http://www.omegatechware.net


Posted by Steve Spence on April 13, 2005, 7:35 pm
 


electronics is 90% efficient. electric to motion back to electric is 60%
efficient. an electric motor(you have two in a rotary inverter) gives
off more heat (inefficiency) than a electronic inverter. The wave form
is true sine however, with a rotary inverter. you may be willing to
trade some efficiency for a better waveform. "sine wave" inverters are
not cheap.


Steve Spence
Dir., Green Trust
http://www.green-trust.org

Contributing Editor
http://www.off-grid.net
http://www.rebelwolf.com/essn.html

Narrff wrote:


Posted by daestrom on April 13, 2005, 9:23 pm
 



And DC motors will have high maintenance issues.  One would have to learn
about re-brushing, seating brushes, cleaning carbon dust, lubricating
bearings.  Adjusting speed and voltage regulators also comes to mind.

daestrom



Posted by Steve Spence on April 14, 2005, 2:14 pm
 

permanently lubricated bearings, and brushless units are available, so
some of this could be worked around. a voltage regulator ic would make
sure that the rpm stays steady as the battery is discharged., and a
feedback circuit could adjust voltage as load changes. dc electronics is
cheap and easy.


Steve Spence
Dir., Green Trust
http://www.green-trust.org

Contributing Editor
http://www.off-grid.net
http://www.rebelwolf.com/essn.html

daestrom wrote:


Posted by Me on April 14, 2005, 5:58 pm
 



Just another note here, Brushless DC Motors of High HP are rare, and
expensive, so a Mogen of any power would consequently expensive.


Me

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