a/c generator

Thread Starter

samjesse

Joined Sep 14, 2008
212
Hi

Is there a portable a/c generator for home/business which automatically controls its output based on consumption demands?
maybe speeds up as demand go up.

thx
 

Brownout

Joined Jan 10, 2012
2,390
Look at the Honda line of portable generators. They have an economy mode, which does exactly what you asked. I own one, and it works great. One caveat, it won't put out maximum power in economy mode. You have to switch it to normal mode. I have plans to modify it to switch automatically.
 

Thread Starter

samjesse

Joined Sep 14, 2008
212
Honda Eco-Throttle, which automatically adjusts the engine speed to match the power needed.This is probably what I am looking for, I hope to find one which runs on LPG. Will keep looking. thank you
 

crutschow

Joined Mar 14, 2008
23,487
Varying the speed to adapt to the load only works for an inverter type generator, which the Honda is. A standard AC generator requires a constant speed to maintain a constant output frequency.
 

Thread Starter

samjesse

Joined Sep 14, 2008
212
Varying the speed to adapt to the load only works for an inverter type generator, which the Honda is. A standard AC generator requires a constant speed to maintain a constant output frequency.
OK. so there maybe an AC generator which controls the output watt (maybe via controlling the strength of the stator magnets) instead of speed. if all are permanent magnet, then maybe modifying an electromagnetic alternator (automotive) and adapt it to work could be a solution.
 

Brownout

Joined Jan 10, 2012
2,390
No, what he's saying is that the output waveform is generated electronically. The generator actually outputs a DC voltage, which is converted to the 60 Hz AC by an electronic inverter. The Honda is so configured. That's how it is able to have the economy setting.
 

GopherT

Joined Nov 23, 2012
8,012
The Honda method is also used in "direct drive" wind turbines. That is, wind turbines that do not have a gear box. These wind turbines are generally more efficient because they can run at any speed proportional to wind speed instead of being governed down to increments to match an available gear ratio. Less maintenance and fewer moving parts on the direct drive model.
 

crutschow

Joined Mar 14, 2008
23,487
OK. so there maybe an AC generator which controls the output watt (maybe via controlling the strength of the stator magnets) instead of speed. if all are permanent magnet, then maybe modifying an electromagnetic alternator (automotive) and adapt it to work could be a solution.
A standard AC motor-generator simply has a governor that adjusts the throttle to maintain a constant speed and have a constant voltage and frequency output with varying load. The gas consumption is thus proportional to load. But, even at no load, there is a significant gas consumption just to keep the high constant speed required to maintain the frequency and voltage.

An inverter type generator can lower the speed of the motor under light or no load for higher efficiency since the AC frequency and voltage is now generated electronically by the inverter. It can operate with the varying input voltage from the DC generator as the speed varies.
 
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