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If you had two three-way switches and one four-way switch, you could wire the three switches the way you would wire a lighting circuit controlled from three places. They are available as products suitable for industrial use. xnuke "Live and act within the limit of your knowledge and keep...

I agree with jghrist - those dimensions look fine for 13.8 kV (see NESC Section 235 for reference). However, the military overhead line construction specification has pretty good pole details similar to the detail you posted. See here, and look under Related Materials for "Pole Details." xnuke...

Distributed energy inverters and battery power converters provide the sync check internally - they sense the AC voltage, frequency, and phase on both sides of their AC contactor and they modulate their output to match the line side before closing. That's why they won't return to operation in...

Bold text are my changes to your text. IEEE 2030.7 calls this the grid-connected steady state. I encourage you to think of solar and wind acting as negative load rather than generation sources since we can't cause their output to go up on command, only down. The battery should be used for...

You're describing an islanding microgrid. When grid connected, the distributed energy resources, i.e., PV, wind, battery energy storage system (BESS) will operate in parallel with the grid. When the grid goes down, a point of interconnection disconnecting device should open to disconnect the...

I'm a former professor at a teaching polytechnic with a MS in engineering and fifteen years of engineering experience before I started my faculty position, and I agree with every point made by Enable. I took a 25% pay cut to take the teaching position, but I did it because I knew I loved...

Sounds like you might want a ratio control loop using measured gas concentration downstream of the mixing point to control the air added with the gas as an uncontrolled variable to get the right mixture. There are multiple ways to do this, e.g., measure gas flow and ratio the measured air flow...

Another vote for delta on the LV side, as it sounds like you have a HRG system at 480 V. You don't want to put in a grounded wye on that side of the transformer with a HRG in the system. I also recommend avoiding both the terms "primary" and "input side" as I've been working a lot with...

Yes, that can happen. Sounds like you may need blocking diodes to prevent reverse current flow. xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

I agree that since feedforward is open-loop, it cannot provide perfect correction, but saying feedback alone works better is not typically correct. Your expectation that feedback does most of the work is in fact backwards in most systems with both feedforward and feedback controllers. As to...

Thanks, seanleed. xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

I realize this question is somewhat customer-specific, but what are people seeing a lot of customers using? 24 V DC? 48 V DC? 125 V DC? 250 V DC? Other? xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please...

Check out AutomationDirect components (I am not affiliated). They have options that are less expensive. xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376 for tips on how to make the best use...

Not true, the cutoff is 1000 V, and has been for several code cycles now. I agree with the others, no one I know uses 690 V, they use 600 V because ANSI standard voltages are integer multiples of 120. That's why the cutoff in the NEC used to be 600 V. My understanding is that it was increased...

You don't need to buy a ductor, you can rent one or find a local company that does electrical testing that owns one and pay them to test your wire. I think that either of those solutions is better and safer than trying to make your own. It will be calibrated, able to deal with drift, and UL...

The delta winding is a stabilizing winding: Link Autotransformers are less expensive due to the power gain associated with their turns ratio. On a much smaller scale, I've used two 1 kVA boost transformers in open delta to serve up to 16.5 kVA of load. xnuke "Live and act within the limit of...

If you want to know power and energy consumption, put an appropriate power meter on the power circuit that can measure what you want to know. They are available with clamp-on leads to measure the current and can clip to voltage terminations. Yes, you can also look at all the compressed air data...

It was in forum248, but is now gone. Someone, probably a moderator, has edited my post above to remove the link I included telling people to post in the other thread, and has deleted the other thread. Please do not post the same question in more than one forum. Now that this is the only thread...

This is a duplicate post and has been red-flagged for deletion. xnuke "Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged. Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

The old school way waross mentioned still works, and doesn't require communication between AVRs because the CT feedback voltage created by the resistor provides negative feedback that eliminates the circulating current that arises. See this paper by Basler: Link. This only stabilizes the system...