[RE-wrenches] motor starting issues (was: offgrid system question)

[Kurt Albershardt]

--On Tuesday, August 19, 2008 7:57 AM -0700 Peter Parrish <peter.parrish at calsolareng.com> wrote:
>
> Any motor will need both a voltage and current to operate properly, and they tend to draw more and more current as the source (inverter) voltage drops.


Back to basic physics:

Depending on design, electric motors can be constant power or constant torque (or some combination of two) devices.

Three phase AC motors are generally simpler in design and better behaved than either either single phase AC motors or DC motors.  Permanent magnet synchronous 3Ø AC motors (available now) closely approach the theoretical limits of electromechanical motor systems in general.

Modern power electronics and control systems give us essentially perfect control of voltage, current, and frequency in AC systems.

Intelligently combining the above allows us to design efficient electromechanical systems which match nearly any complex supply impedance.  These systems also happen to live longer, fail less often, and reduce both battery bank and inverter requirements.

The market (arguably free on so many levels, and obviously not on so many others) can address this using current technology.   System sizing math not has changed fundamentally in several decades but we are getting closer to those fundamental limits.

Industrial systems are a bit ahead of the consumer market in some areas but behind in others.  As one very basic example, Turbocor's maglev compressor has created a few waves in the commercial and light industrial sector but I fully expect some fascinating trickle-down benefits over next few years <http://www.turbocor.com/products_technology/>







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