240v Vacuum Oven in the USA at 110v - Page 1
Forum section: electronics / general

author: Jaxmoto
author_rank: Contributor
timestamp: March 08, 2014, 08:26:12 pm
content: So I lucked out and picked up a vacuum oven at a local outdoor market fairly cheap. Came out of a large lot of lab equipment.However there were no obvious markings on it to say it was Australian. So when I got home I realized it is an Australian 240v oven, a Semsa VAC30D.http://www.semsa.com.au/vacuum%20ovens/vacuum%20ovens.htmsecond model down.Bought it to resell as it is in immaculate condition but not sure how to even test the thing. 1250w is far too much for a reasonable step up and nothing I can find in industrial or medical uses 240v. I've got 220v at the house, but I'm worried I'll burn up something running 220v/60hz through a 240v/50hz machine at this high a wattage.So is there any way to make proper use of this thing in the US on 110v? There is just one plate on the side that shows 240v/1250w and the serial number, so it doesn't look to be dual voltage.I also have no idea why it is here. It weighs about 70-80 lbs and to ship from AU would be ridiculously expensive, so I have no idea why someone brought it here.Any advice is appreciated.

author: IanB
author_rank: Super Contributor
timestamp: March 08, 2014, 08:55:06 pm
content: If you put your meter on it, I suspect you will find the "220 V" at your house is actually 240 V.But the different mains frequency may not always be a problem. It is no problem for heaters, and rarely a problem for transformers. It could be a problem for AC motors (which will run at a different speed). However, if this oven is already in the USA it is likely that the previous owner was running it from a local 240 V 60 Hz supply and therefore it will probably work.

author: Jaxmoto
author_rank: Contributor
timestamp: March 08, 2014, 09:35:38 pm
content: Thanks, I'll give it a shot. Now I just have to find a 220v appliance plug adapter to a AU plug.

author: Monkeh
author_rank: Super Contributor
timestamp: March 08, 2014, 09:39:08 pm
content: Why use an adapter?Cut the plug off and put the right one on!

author: Jaxmoto
author_rank: Contributor
timestamp: March 08, 2014, 10:24:39 pm
content: The only 220v (runs about 240v) I have is an appliance line. In the US appliance lines run hot/hot/neutral (110v/110v/neutral). The AU plug is hot/neutral/ground. Can't just swap the plug.

author: Monkeh
author_rank: Super Contributor
timestamp: March 08, 2014, 10:27:00 pm
content: Quote from: Jaxmoto on March 08, 2014, 10:24:39 pm...So what, exactly, is an adapter going to do that the correct plug can't? You have three wires in the cable, that won't change. But you only need three.The only thing to consider is fusing.

author: IanB
author_rank: Super Contributor
timestamp: March 08, 2014, 11:34:43 pm
content: Quote from: Jaxmoto on March 08, 2014, 10:24:39 pmOf course you can.I have an electric kettle imported from Europe. In Europe the wires in the power cord are designated live-neutral-earth. However, the designers of the kettle cannot guarantee that the mains will be correctly wired (or even that the mains plug will be polarized, e.g. Schuko), so both live and neutral wires are equally and fully insulated. When I cut off the European plug and fitted an American NEMA 6-15 plug in its place, I wired live and neutral to the two 240 V hot pins and wired earth to the ground pin. It works fine.

author: Jaxmoto
author_rank: Contributor
timestamp: March 09, 2014, 01:52:08 am
content: If I had a Nema 6 style plug it wouldn't be an issue, I could just swap it over. All I have is a dryer plug which is like a Nema 15, 3 wire and ground. It doesn't actually have 240 on it, it has 110/110/Neutral/ground.I can wire in one but that is a lot of work with putting in a new breaker and wiring it to a temporary recepticle and swapping out the plug.

author: Monkeh
author_rank: Super Contributor
timestamp: March 09, 2014, 02:25:18 am
content: Quote from: Jaxmoto on March 09, 2014, 01:52:08 amMeasure the voltage between the two 'hot' contacts. You may make a remarkable discovery.

author: SeanB
author_rank: Super Contributor
timestamp: March 09, 2014, 06:56:24 am
content: Live (brown) to the one 110V, neutral (blue) to the other and ground ( green/yellow) to ground. That will work.

author: Jaxmoto
author_rank: Contributor
timestamp: March 10, 2014, 08:42:38 pm
content: Thanks all, I got it going. The transformer in it is rated 50/60hz so I think it will be fine running on American 240.Sorry if the questions were basic stuff, I just never mess with AC and my mind always wants to think in terms of DC.

author: tsmith35
author_rank: Frequent Contributor
timestamp: March 10, 2014, 09:02:22 pm
content: Just to throw this out... normal US household voltage was often referred to by some as being 110V, while others referred to it as 115V or 120V. Modern wiring tends to be less lossy than older wiring, so what you get in your house is probably closer to 120V than 110V. My service tends to run at around 121-122V, so my "240V" actually runs somewhere around 242-244V.A plant I worked at in the past had about 108V available at office receptacles, while the voltage at my last previous house tended to run a bit hot: 123-124V depending on the day. Once I discovered that, I understood why my 120V GE incandescent lamps burned out quickly, while the contractor-installed lamps (rated at 130V) seemed to last forever.Anyway, here's some interesting reading:http://en.wikipedia.org/wiki/Mains_electricity#Standardization

author: electronics man
author_rank: Frequent Contributor
timestamp: March 13, 2014, 06:35:50 pm
content: This may be different to in the us but in the uk everything is rated to be 230v - 250v so it doesn't realy matter.