Is this mains filter safe? - Page 1
Forum section: electronics / projects

author: justinjja
author_rank: Regular Contributor
timestamp: January 07, 2017, 05:22:01 am
content: EDIT::Just incase google sends anyone here, I would recommend buying this filter instead:https://www.amazon.com/Tripp-Lite-IBR-12-TRIPPLITE/dp/B017O2XGWU/ref=sr_1_1?ie=UTF8&qid=1484360162&sr=8-1&keywords=ibr+12picked one up on ebay for about $40 shipped, and it works much better:Speed test results:Everything turned off in garage speed: 20mbpsEverything turned on in garage, no filter: 0mpbs (fail to connect)Everything turned on in garage, Smarthome filter: 3mbpsEverything turned on in garage, Tripplite filter: 15mbps/EDITI blew the fuse in this filter, so I decided to take it apart.Seems like that 2.2uF cap could be charged anywhere up to 170V when this device is unplugged right?There doesn't appear to be anything to discharge it,its a metalized polyester film capacitor.https://www.amazon.com/Smarthome-1626-10-FilterLinc-10-Amp-Filter/dp/B003ICY1S4/ref=sr_1_1?ie=UTF8&qid=1483766221&sr=8-1&keywords=insteon+filter

author: BradC
author_rank: Super Contributor
timestamp: January 07, 2017, 05:59:30 am
content: I've had a belt or two over the years from similarly designed filters. The old Epson fx-80 had a particularly nasty one that resulted in it being involuntarily thrown across a room. It survived. They don't build them like that anymore.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 07, 2017, 06:11:26 am
content: A 2.2uF cap charged to 170V stores too little energy to be a real hazard. Not much more than ESD. Some high power multisection mains filters like those used on shielded test rooms can store enough energy to be hazardous and have warning labels regarding that.What I would be concerned about is that it could be a fire hazard if the cap is not X rated. Also, the neutral passing straight through and no Y rated caps to ground would likely limit the effectiveness of the filter.

author: justinjja
author_rank: Regular Contributor
timestamp: January 07, 2017, 07:06:09 am
content: It actually does work for me.I have a Powerline adapter that doesn't work at all with my server turned on.Plugged in the server through that adapter and problem solved.I replaced the fuse and plugged it in for a second then unplugged it, and measured 100v across the leads of it.Considering how strict most electric codes seem to be, I would have expected a warning label or something.

author: SeanB
author_rank: Super Contributor
timestamp: January 07, 2017, 09:54:04 am
content: Should have a 1M 1W 500v rated resistor across it, and really is a third harmonic mains filter, designed to reduce the distortion sent back up the mains from diodes on the secondary side ( or the primary side on a SMPS) conducting at near the peak of the mains cycle.Was a common add on to solve third harmonic distortion requirements before they introduced the lower power standby requirements on power supplies in IT equipment. Seen plenty of computer power supplies with this done, and a fair number of cheap fakes where the inductors are merely a loop of wire through a former and wrapped with tape as well.

author: German_EE
author_rank: Super Contributor
timestamp: January 07, 2017, 01:51:52 pm
content: Just add a 1M ohm 1W resistor across the mains output, after the power is removed the capacitor will discharge through the resistor and the inductor.