New answers tagged

0

I do this with a length of wire going to left or right channel and on the microphone jack on a sound card or mic jack on laptop. Picks up the 50 hz no problem. Read the port with python, write a .wav file. Plot, Fourier transform. I can see that the power company adjust the frequency every half hour,


0

It's grounded in order to complete the circuit. If it weren't grounded and the customer didn't ground their neutral bar or tie the earth bar to it, then there would be no way for earth current to get back to the transformer (except through a neighbour's earth, which isn't ideal). The customer would then have a floating ground assuming no neighbour earths ...


0

... the manufacturer datasheet specifies the resistance in ohm/km (R). Does this imply the resistance per conductor core or is it for all the three cores added together? The resistance will be per conductor core. For a twin cable you might see resistance specified "per km loop" which would mean the out and return resistance. Power loss is simply \$...


1

This claims an isolation of 2.5kV RMS. Maybe that's fine, but it's difficult to say unless you're working against a specific requirement. Adding some kind of surge protection is not a bad idea. Consider an R1 + C1 series, MOV in parallel, R2 + C2 + input diode in series. Caps are nice because they reduce the amount of thermal dissipation. Analyse the ...


5

Though not ideal, each 100 kΩ resistor, by itself, would limit fault current to ~1.2 mA, generally considered safe on skin contact. Of course, a resistor failure could make the the circuit "live"... but if the optocouplers are in an effective enclosure, and the only wires or traces leaving enclosure are from the output side, the 5,000 V isolation ...


1

I think I've found a really good workaround solution for this. I'm trying to do exactly the same thing - use my excess solar power to heat my water. It is a 4,800W heater and I typically have 3,000W of excess solar at maximum for 3hiurss a day. I need to somehow throttle my heater to 1-2kw or so. I've been looking at high power motor controllers, triacs ...


1

Measure the voltage (ac range on the multimeter) between mains earth and Arduino 0V. Should be around 110Vac if the laptop charger is plugged in. Repeat measurement with the charger unplugged. I’d suggest grounding the usb shield to mains earth to avoid any current through the Arduino.


0

Judging from the transparent looks, it is a rectifier, electrolytic storage cap and series cap before the rectifier (see JREs comment) This series capacitor will make the LEDs rather dim when using lower voltage, so you need to change or parallel them with a larger one.


1

I have directly connected 120VAC mains to a voltage divider and directly digitized that and it works fine, although you really really do have to be careful about having energized neturals/grounds and stuff like that, which you seem to be aware of. Note that it is probably a good idea to put transient protection on one or both sides of the bridge if you want ...


2

Most audio circuits have a low-end cutoff frequency in the 20 Hz range. So, even at 50/60 Hz, they will have a small attenuation, and a noticeable phase shift (perhaps 10-20 degrees). Why do you care about the waveform so much ? The AC line is quite 'dirty' and most loads don't care. Motors and (incandescent) lamps don't care. Laptops, TVs, and other loads ...


0

To answer your questions: "Is this ripple problematic for a DC/DC converter?" The ripple at the output is directly related to your output capacitor and your output inductor. If your ripple is too high that means the current through the inductor is too high or your output capacitor is too low. In the case that your output cap is too low there's ...


0

I fully agree with @ Oilin Lathrop's response and comments. I can suggest the use of the product TRIAC BTA100 Series. In this case, a single piece will be able to control all the current demanded by the load.


0

I really like the sound of a sine pulse that @CharlesCowie suggested. Unfortunately, it seems a little ambiguous to me whether it refers to a half sine cycle or a full sine cycle. I propose a sine lobe. It does not sound as good as the sine pulse but I believe is less ambiguous.


0

If it's inline with the mains supply then it can only measure that AC supply. Voltage and current readings will be AC. If you have further specific questions then please link to the manual in your question.


0

I remember that GE's Multilin SR750 feeder protection relay provides synchronous bus transfer. We could set maximum voltsge and angle differences between a bus transfer could be activated. It ensures break before make transfer. Many other suppliers may offer similar features. It is also not advisable to parallel two informers even momentarily as the circuit ...


0

ATS are designed to be break-before make, to avoid the case where the genset is connected to the utility (a very bad thing for many reasons, and generally not allowed.) When the ATS transfers, it would be as if the supply were interrupted briefly. You mention 50ms dropout time. This is several cycles. There's no guarantee that the phase alignment of the ...


0

My opinion is that some people will hold the hand-held phone with the finger or the hand directly touching the USB phone charging cable. If the USB charger is faulty, AC current will flow through the charging cable and pass to the human body as conductor and then goes to ground either through the feet of the human body to the earth ground ground or to the ...


Top 50 recent answers are included