Dumpster dive transformer less inverters - teardowns to come later - Page 1
Forum section: electronics / general

author: station240
author_rank: Unknown
timestamp: October 05, 2015, 09:22:14 am
content: My area doesn't have hard rubbish collection, but I still managed to get things this past month.First thing I got was a Sunny Roo 5000, 5000w Solar Inverter.Apparently dead, but so far I've not found faults. General thoughts are it's just got some minor design issues related to software/monitoring and throws errors/disconnects easily. Also smells of cheap crappy caps after my last test where I fed 375V DC into the solar PV inputs.Being a grid interactive inverter, I really need a fake grid to connect it to, or a better output stage.Then I got a second bigger inverter.MGE Comet S31 20Kva UPSActive power: 16KwInput: 3 phase 415V ACBattery voltage: 288V DC nominalOutput: single phase 240V ACNet weight without battery: 210 KgThe solar inverter is 28Kg and wall mountable, the huge UPS is fridge sized and probably heavier than a dumpster.Neither have anything more than a very basic block diagram, so I'm making my own. At a basic level both have a Boost Inverter and an output inverter, the only transformers are tiny ones confined to the LV supplies to the electronics.UPS teardown, testing, etc is up to day 4 now.

author: necessaryevil
author_rank: Regular Contributor
timestamp: October 05, 2015, 10:01:26 am
content: Can't wait to see this one! I love the bigger stuff, I started my hobby with tearing down industrial stuff from my uncle's company when I was a kid. In the mean while, watch this one (no not me):

author: station240
author_rank: Unknown
timestamp: October 31, 2015, 01:21:40 pm
content: Still working on this, want to have proper block diagrams, as the company supplied ones are very basic.Discovered some technical info not present in the published info.Main DC bus: +199V 0V -199VAlso the inverter won't sync until the grid is functioning. So if you turn it off during a blackout, it won't restart.The Battery charger is easily disabled by unplugging a 12 pin plug with thick cables.Seems it will take any suitable voltage as an input on the battery terminals, could be the same for the 3 phase inputs.Below is the battery cable I got with it, ran to an external battery cabinet. Batteries use the same 0V center tap arrangement as the main capacitor bank, +144V earth -144V.

author: AF6LJ
author_rank: Unknown
timestamp: October 31, 2015, 03:09:47 pm
content: Thanks for Sharing.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: October 31, 2015, 06:46:35 pm
content: Quote from: station240 on October 05, 2015, 09:22:14 amWelcome to the club !I have a similar one that I still need to move.It is so heavy that I will have to take it in parts, so I will be looking for your teardown.I have just moved the batteries, but the remaining part is still too heavy.How did you manage to get it from the dumpster ?

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 01, 2015, 03:48:49 pm
content: Open it up and remove the big transformers (noting where they connected if you intend to reassemble and use it) and that will considerably reduce the weight.

author: station240
author_rank: Unknown
timestamp: November 01, 2015, 04:46:40 pm
content: Quote from: JacquesBBB on October 31, 2015, 06:46:35 pmYes it's still 150Kg without batteries, as for how I managed to get it home.Well two men got in into a trailer by using the wheels to move it, then used a makeshift ramp (timber and bits of timber packing crates) to load it onto a trailer. It arrived on it's side as they tipped it over to get it loaded. Not sure exactly how they did it, not recommended.Jacques mind if I use your photo, I don't have any of the internal batteries installed, as mine came sans batteries.@NiHaoMike It's transformerless, would be far heavier if it wasn't.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: November 01, 2015, 06:21:01 pm
content: Quote from: station240 on November 01, 2015, 04:46:40 pmNow I understand. It was not so easy. As I want to transport it in my car (sedan), this is why I willtry to dismount it as much as possible.QuoteNo problem, be my guest !I had about 200 kg of batteries. I intend to revitalise them. I found that most, if not all have lost a lot of water.Just adding some water already revive them to decent voltage.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 02, 2015, 05:12:17 am
content: From the picture, there appears to be a big transformer or transformer-like object (inductor?) behind the vent.