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3 votes

Are AC generators more efficient than DC generators?

You can have brushless DC as well, but its all a balancing game of cost over its lifetime. Efficiency only matters when the entirety of the process is considered. One high efficiency process can be ...
Abel's user avatar
  • 1,352
3 votes
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Arduino DAC to Speaker

Your understanding of the issues is good. Q1: It's not overkill at all. All of the elements you've mentioned are needed. Q2: The low-pass filter frequency needs to significantly attenuate all ...
Graham Stevenson's user avatar
3 votes
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Is a 3 Hz beat frequency from my neighbor's HVAC a sign of a malfunction?

A 3Hz pulsating hum-- noise that is getting louder and softer at 3Hz. Yes, I agree that would be quite annoying. Since this is a residential unit in the US, both the compressor and the fan are run ...
user1683793's user avatar
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2 votes
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AC induction motor

It could, yes. But the tradeoff would be worse performance. The strength magnetic field is a function of distance from the coil, so increasing the volume by turning your rotor into a fan shape would ...
ericksonla's user avatar
1 vote
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Basic questions about power grid stability with variable loads and sources

In a traditional grid, the frequency stability is maintained by the rotating mass of the generator set. If the generator suddenly becomes easier to spin, or more difficult to spin, (because you have ...
david's user avatar
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1 vote
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AC/DC Laptop adapter power losses

Lenovo ADL170NLC3A has an Energy Star V (ES 2.0) rating. Energy Star states to get that rating for nameplate output power ($P_{no}$) > 45W, the Minimum Average Efficiency in Active Mode ≥ 87%. At ...
StainlessSteelRat's user avatar
1 vote

How to convert VDC to VAC at a high frequency?

You want something called a oscillator. It is powered from DC, and produces AC output, usually a sine or square wave. For the case of 10 MHz, you can use a resonant design since the components can ...
Olin Lathrop's user avatar
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1 vote

How does single-phase AC synchronous motor work?

I've got a few of the circular motors in my junk box and took one apart. With what I've found on the net, and what I see in the unit I have, here is what I found. The circular units are for very ...
Neal Vance's user avatar
1 vote

Does a transformer use power when output isn't under load?

Energy delivered to the primary goes to: The secondary load, off coarse, zero if no load, Copper losses: both primary and secondary IR losses of winding resistance. If the secondary has no load, that ...
pinky's user avatar
  • 11
1 vote

Design of a hydrogen and corrosion sensor query

Are you making a corrosion sensor or a hydrogen sensor ? Corrosion sensors ( corrosion probes) ,based on metal loss have been around for over 50 years. And hydrogen is a special problem , strongly ...
blacksmith37's user avatar
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1 vote
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Calculate amount of evaporative coolers needed to cool down an area

Foundations (Energy Balance) For the Room Consider the system shown in the picture below. Air flows through a room volume (area and height) with a residence time. Heat is provided by people inside ...
Jeffrey J Weimer's user avatar
1 vote

Which Generator is "Better": DC or AC?

AC generators are simpler. Their inherent construction property is that the sine wave of AC is directly derived from the rotary motion of the rotor. There is no commutator, which is a part that ...
SF.'s user avatar
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1 vote
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Are there any variable frequency drives that work digitally?

This question is rather confused, but I'll take it as "Can AC power be produced from DC power without mechanically moving parts". Of course. That's what devices called "inverters" do. Most ...
Olin Lathrop's user avatar
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1 vote

Increasing speed and efficiency of ac induction motor

A possible avenue you could look at is the motor controllers that match power to load.
Solar Mike's user avatar
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1 vote
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Increasing speed and efficiency of ac induction motor

You really can't change the frequency of alternating current. This is fixed at 60 hertz (cycles/sec) for USA and 50 hertz most everywhere else. by laminating the permanent magnets you reduce losses ...
0tyranny0poverty's user avatar
1 vote
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Mechanically increasing RPM of ac induction motor

A standard induction motor has to turn at the speed determined by the current frequency. If you attempt to apply external torque to drive it faster it will act as a brake resisting that torque. If ...
agentp's user avatar
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