| General > General Technical Chat |
| Has anyone seen this - Voltserver: "Digital Electricity" |
| << < (15/20) > >> |
| ogden:
--- Quote from: Cyberdragon on February 17, 2018, 07:42:08 pm ---If you are "packetizing the power" itself, you are BY DEFINITION sending it in PULSES. Which brings us back to my original point that you will need CAPACITORS to convert this into clean DC power for a device to operate. Let alone the physics of why this is more complicated than normal rectifier ripple filtering. https://en.m.wikipedia.org/wiki/Filter_capacitor --- End quote --- Right. This is why I did LTspice simulation to show you that offered tech needs smaller capacitors than existing 50/60Hz systems: Seems, you are not able to comprehend information provided. [edit] Which leads to obvious question: what the heck you are doing in this discussion? --- Quote ---Why would you pulse the power? This is totally pointless! :palm: What purpose would anyone have to overcomplicate things? --- End quote --- Power pulsing is needed for power AND fault detection. While you provide power - it is hard to detect someone touching wires. Indeed you need "fault detection" phase. During 1.1ms they provide power, next 0.4ms they communicate to load and at the same time they check for faults like human connected somewhere. --- Quote ---If it's also modulating the pulses to communicate, then WHY? --- End quote --- Fault detection, on/off state communication, dimmer settings and so on. --- Quote ---What possible data would a device need to communicate to it's power source? Control data? That's what POE is for! --- End quote --- PoE is for 1) data that is not related to power, transmission 2) power provision. PoE does not transmit for example dimmer settings. --- Quote ---You can also impose the data OVER the power without ever pulsing the power itself! --- End quote --- They are not pulsing power to modulate data. On/Off keying of power for data transmission is just your uneducated assumption. --- Quote ---You've yet to give us any specific examples of any specific uses, let alone advanges, of this! Untill you do (give us examples and advantages), this crap is going under STUPID, and SNAKE OIL! --- End quote --- More than 100W power over twisted-pair cables like Cat6. Cellular network providers are hungry for such. They state that big displays (TVs) are / can be powered as well. There are loads of applications that can benefit from cabling that is not regulated in same safety category as AC mains. |
| Cyberdragon:
So it's pulsing at about 900 something hertz (or whatever they actually use) and transmitting between them. You're still using capacitors (where DC wouldn't, or would be even smaller just for voltage drop suppression), and as you even said you'd need slew control and other complex EMI solutions over normal power (especially at high power). It doesn't have to do with the frequency of the power either, it's the sharp edges that have to be suppressed (hence the above). Normal DC also does not experience inductive losses, which pulsed DC will (and greater than normal AC at lower frequency). Also look up the "skin effect" (related to inductive losses). Plus that's not including power factor, which may cause weird effects with your slew control! http://suddendocs.samtec.com/notesandwhitepapers/simplified-pulse-current.pdf As NiHaoMike said about transmitting between packets, this isn't very efficient for bandwidth. There are normal systems that use data over top of power, which have much higher bandwidth and can do all you described while using normal DC or AC power. Like I said, you'd never have to pulse the power (even to send data in between)! So the only thing this has going for it is this so called "Safe Touch" fault detection. You can do short circuit and arc suppression on normal systems, it's not new. Explain exactly how it's supposed to detect a person across the lines in these off periods and turn off the power faster than you can feel it (at whatever Hz too)? Remember, a person is just a resistance, so across the lines it just looks like a load. Are they using impedance testing? And I won't be satisfied until SOMEONE puts their hands across it and PROVES it's safe. (at least with that saw thing they used a sausage, although for this a person is required because a sausage can't feel a shock) --- Quote ---More than 100W power over twisted-pair cables like Cat6. Cellular network providers are hungry for such. They state that big displays (TVs) are / can be powered as well. There are loads of applications that can benefit from cabling that is not regulated in same safety category as AC mains. --- End quote --- "They state that" I don't care what the marketing dept says, I care about science! Over 100W over CAT6?! First of all, is CAT6 even rated for 300V? I don't think codes would allow that, so you'd have to use mains cable anyway just due to the voltage involved! At 300V 100W the current is 1/3 Amp. CAT6 is (generously) 24AWG, which means a max rating about 0.6 Amp. However, it's pulsed, so due to having a duty cycle the instantaneous current is actually greater than 1/3 Amp! The cooling effects won't be much either at that frequency! It may not burn up, but it'll still get warm and the temp will have to be considered. You can experiment with this at home too, just use a 100W audio amp and a slew controlled square wave at whatever their frequency is and feed it flat out into a speaker through a long piece of CAT6 for a long time. Now tell me the results. Did it get warm? What was the distortion? |
| PlainName:
--- Quote --- and turn off the power faster than you can feel it --- End quote --- Wrong end of stick. The power is turned ON unless the previous pulse was determined to be 'safe'. That's the point of the pulses - individually they are safe and it only takes one bad one to bring the system to a complete halt. --- Quote ---which means a max rating about 0.6 Amp --- End quote --- At 300V is 180W --- Quote ---use a 100W audio amp --- End quote --- I suspect your average audio amp isn't going to put out 300V, so the current will be enough to damage the wire. Testing with the wrong tool gives misleading results. |
| Cyberdragon:
--- Quote from: dunkemhigh on February 17, 2018, 11:07:11 pm --- --- Quote --- and turn off the power faster than you can feel it --- End quote --- Wrong end of stick. The power is turned ON unless the previous pulse was determined to be 'safe'. That's the point of the pulses - individually they are safe and it only takes one bad one to bring the system to a complete halt. --- End quote --- But HOW are you determining if it's safe? Also, again, it would still have to react within a millisecond! 100W over 180W absulute max rated wire (IE it burns out past this), is going to get hot and is quite a dodgy thing to do. |
| ogden:
--- Quote from: Cyberdragon on February 17, 2018, 10:19:08 pm ---So it's pulsing at about 900 something hertz (or whatever they actually use) --- End quote --- You can't even do elementary math for 1.5ms period :palm: --- Quote ---You're still using capacitors (where DC wouldn't, or would be even smaller just for voltage drop suppression), and as you even said you'd need slew control and other complex EMI solutions over normal power (especially at high power). It doesn't have to do with the frequency of the power either, it's the sharp edges that have to be suppressed (hence the above). Normal DC also does not experience inductive losses, which pulsed DC will --- End quote --- :blah: Your offer to use unprotected >= 350V DC is uneducated to say it politely. --- Quote ---As NiHaoMike said about transmitting between packets, this isn't very efficient for bandwidth. There are normal systems that use data over top of power, which have much higher bandwidth and can do all you described while using normal DC or AC power. Like I said, you'd never have to pulse the power (even to send data in between)! --- End quote --- Oh, geez :palm: Efficient for bandwidth? How much bandwidth is needed to tell LED it's dimmer setting? --- Quote ---And I won't be satisfied until SOMEONE puts their hands across it and PROVES it's safe. --- End quote --- It's shown in the video which you refused to watch :-DD --- Quote ---"They state that" I don't care what the marketing dept says, I care about science! --- End quote --- Science? How about pilot installations which are working well? --- Quote ---Over 100W over CAT6?! First of all, is CAT6 even rated for 300V? --- End quote --- Yes, it is. Geez, how many times I have to counter your ignorance/stupidity/whatever? |
| Navigation |
| Message Index |
| Next page |
| Previous page |