Our group sets up at convention centers and besides all the other safeguards I was wondering if we should also include an AC filter between house power and any/all equipment. This question stems from the twisted wire recommendation to reduce RF and any other possible line noise. http://en.wikipedia.org/wiki/Line_filter
John, It would help, if you could describe exactly what you are trying to protect from RF interference (like RF remote controllers?). But from what I understand from you post, I would not add complexity when there is no apparent existing problem. Bob
My question is more around any noise in the supplied power from the convention center or house on large layouts. Maybe this will help explain where I am coming from. https://sites.google.com/site/markg...ning/twisted-pair-wiring/technical-discussion
John, from: https://sites.google.com/site/markg...iscussions/wiring-planing/twisted-pair-wiring “Where can you use Twisted Pair Wiring? Any where a pair of wires need to carry power or information in the form of an AC current that needs to run long distances with minimal loss of signal integrity and maintain high speed. In other words, where reliable communication and control must be established over long wire runs. A common example of twisted pair wiring is found in ethernet cables used to connect computers together.” So unless the AC lines are also carrying a signal that requires reliable communication and control over long wire runs, there is no good "RF interference" reason that I know of to twist them or add an add an AC power filter. Bob
Thanks for your responses Bob. I am not real savvy on how electricity can behave so my questions come from the end user perspective. Let me give an example of what motivates my question. I have stood on the supply cord between the outlet and power supplies for the DCC system (command station plus 5 boosters) and it feels like water running. It seems like there was excessive power running about, and it makes me think it may need some kind of regulator of sorts. Since our DCC bus has a signal in it I thought maybe if there was a solid base power that was clean to start with would better help us have a reliable system. Outside any connection issues. I hope this better explains where I am coming from.
It is probably a good idea to isolate the DCC equipment from the "house power' at convention or other sites. The noise on the power from the venue will find its way into the DCC controller and possibly affect the purity of the signal. Noise is a nasty thing to deal with in electrical systems, and if you feel that the power is dirty, you could easily get an Uninterruptable Power Supply from APC or similar that isolates the venue power and regenerates clean power. I have been to shows where we did use an APC unit because the power was historically bad. As for RF resistance, using just Zip Cord is about as much as is needed for any suppression. In order for twisted pairs to really be effective, the DCC pulse repetition frequency would need to be a great deal higher in frequency, and you would also need to know what RF frequencies you were trying to protect from because that is a part of the calculation of the twist rate of the wires. he reason Zip wire is fine is because at the DCC frequencies, 80% of the power lies between the conductors with a very substantial power density that helps resist the RF interference.
Thanks David, would something like one of these do? http://www.newegg.com/Product/Product.aspx?Item=12-220-095 Or is the UPS the only type that will do the job. Just trying to keep the costs down, but if a UPS is the only real protection I will buy one.
Hi John, A normal surge suppressor does little or no real noise filtering. What works best is a battery backup unit that uses line in from the event to charge the battery, and then uses battery power to generate a crisp clear and clean power. This also helps to regulate the power in case of spikes and over-voltages as well as adding power back if the voltage drops low like a faint brownout. A unit like this is the best insurance policy to protect the DCC electronics: http://www.bestbuy.com/site/back-ups-xs-1500-va-tower-ups/9307831.p?id=1218081367518&skuId=9307831&st=categoryid$abcat0515042&cp=1&lp=10#tab=overview This is just a random selection to use as a guide. The key is to find one that will generate the power, not just pass it through. I hope this helps with your question.
Understood David. Thanks much. I am not sure I have everyone in the group on board with this so will likely have to find a way to fund it myself.
