Looking for recommendations on 110V/60Hz in 220V/60Hz out transformer ~ 2k Watts - Page 1
Forum section: electronics / general

author: Electro Fan
author_rank: Super Contributor
timestamp: February 27, 2018, 11:21:40 pm
content: Anyone have any recommendations on a 110V/60Hz input 220V/60Hz output transformer in the 1500 - 2500 Watt range?Other than meeting the voltage, frequency, and wattage specs, and providing good reliability, the next best attributes would be light weight and compact size. First choice would be from a supplier in the US but sources in Europe or elsewhere would be ok too.Thanks for any suggested manufacturers/models or suppliers.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 28, 2018, 01:47:42 am
content: The laws of physics dictate how small a 2kW 60Hz transformer can be. Which is to say not small or light by common definitions. Additionally, 1800W is the limit of a common 15A circuit so such a device is going to require a 20A outlet.That said, there is a trick that can be done with power electronics. Rectify the 120V AC to get +-170V. Then put that through a simple 2 transistor inverter to get 120V AC of the opposite phase. Connect the load between the output of the inverter and the incoming hot to get 240V differential.

author: Gregg
author_rank: Super Contributor
timestamp: February 28, 2018, 03:38:52 am
content: Does the transformer need to be isolated and does the 220V secondary need to be center tapped? There are a number of step up auto-transformers on Amazon of reasonable quality with nice enclosures. If you are looking for isolation look into industrial control transformers, they are quite common for 480 / 240 volt primaries to 120V secondaries for controls, relays etc on large machines and should be available used (old school heavy laminations, real copper windings and rugged reliability.

author: Electro Fan
author_rank: Super Contributor
timestamp: February 28, 2018, 04:18:59 am
content: Thanks for the replies.I've been looking through the Amazon auto transformers - a couple models that look like they meet the requirements are these:https://www.amazon.com/dp/B008GQTW7W/ref=psdc_10967761_t3_B00ER52DMW?th=1https://www.amazon.com/ELC-T-3000-3000-Watt-Converter-Transformer/dp/B00ER52DMW20 Amps will be available. It's going to occasionally run a small combination washing machine/dryer. Not sure how important or preferable a fully isolated design would be for this situation. I think an auto transformer will be ok.One of the Amazon models should do it but Thx for any further advice.

author: tooki
author_rank: Super Contributor
timestamp: February 28, 2018, 05:37:07 pm
content: Quote from: Electro Fan on February 28, 2018, 04:18:59 amWhy not just get a proper voltage appliance?!?If you can't be talked into replacing it, is the appliance made for 230V single-phase (for example, for a normal European outlet), or American 240V split-phase (like an American clothes dryer)?

author: Shock
author_rank: Super Contributor
timestamp: February 28, 2018, 08:08:12 pm
content: I use an auto transformer, mine is step up and down. If you decide to go the auto transformer route a few tips I can offer:Good to assume that unless you get a datasheet saying otherwise an auto transformer will need to be rated 2-3 times above the max power of the device. Obviously you can do your own tests, but just putting it out there. e.g.http://www.sevenstar.com/transformer-guide.htmMine is Seven Star branded and "rated" at 3000W, I wouldn't recommend this brand (though it may be better than others). The socket contacts where really cheap (soldered) and needed tightening, I also tested and traced out the wiring and importantly earthing to make sure it was safe. That said, it was dirt cheap secondhand and does the job.Not sure what device you're powering but some have a selectable input like mine, it may allow you to tweak between 220V-240V. I wanted the option of between 110V-120V output, so I'm running mine a little "hot" to get a nice 120V. The device I'm currently powering would be lucky to draw 100W but I brought it to cover most situations.If you want as small as possible go for (or make) one that has the bare transformer with end covers. A transformer in a box increases the size substantially.

author: tooki
author_rank: Super Contributor
timestamp: February 28, 2018, 10:20:37 pm
content: 120V isn't "hot", it's the nominal value. It hasn't been nominal 110V for something like 70 years…

author: Shock
author_rank: Super Contributor
timestamp: February 28, 2018, 11:12:00 pm
content: Quote from: tooki on February 28, 2018, 10:20:37 pmHot is a common term for over driving an input to get a desired output.

author: tooki
author_rank: Super Contributor
timestamp: March 01, 2018, 12:28:07 am
content: Why would you need to overdrive the input to get 120V out, unless the thing is poorly designed, following the electrical standards of my grandparents' era?

author: Shock
author_rank: Super Contributor
timestamp: March 01, 2018, 03:14:16 am
content: Quote from: tooki on March 01, 2018, 12:28:07 amBecause it's not a variable auto transformer it's a selectable input auto transformer with a 110V output.I'm not sure if it follows the standards of your grandparents era. Do you have a history of teenage pregnancies in your family? If so, you could be onto something.

author: tooki
author_rank: Super Contributor
timestamp: March 01, 2018, 06:47:55 pm
content: Quote from: Shock on March 01, 2018, 03:14:16 amThe nominal voltage was raised from 110 (to 115)in the 1930s. So yeah, I think my statement stands. If anything, my original “something like 70 years” was on the short side...The bump to 120V nominal didn’t happen until 1984, granted.