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Aussie style electrical plug in 1915 US patent
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Location: Oradell, US
Member since 2 April 2010
Member #: 643
Postcount: 833
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This dates back to 1915, don't know if this patent came out before, or after, this 3 prong plug became the Australian standard.
Seems that these crowfoot connectors have existed as far back as 1916, as seen at the US Patent office http://patft.uspto.gov/netahtml/PTO/srchnum.htm, look for patent number 1179728 (type this number in the search box, and on the next screen click "images" and look at figures 3 and 4. You may need the plug in from http://www.alternatiff.com/.
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7444
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Being at work I don't have access to any of my material on Australia's adoption of electrical accessories. Along with a lot of other things, with Australia's electrical supply we tended to do one of three things:-
1. Invent or develop our own products.
2. Adopt the best the best of British.
3. Adopt the best of American.
... pretty much in that order.
Australia invented things like the humble BP (Blue Point) connector and conduit fittings that clip onto split seam pipe, hence the later adoption of the brand "Clipsal", a play on the "clips all" functionality of such conduit fittings.
On the other hand, the adoption of the British 415/240 volt three phase AC supply and a modified version of the US Hubbel three pin plug came to suppliment local developments. I think the pins on the Australian version of this plug are slightly longer.
The three pin plug came into widespread use much later than was probably planned though. For a long time we survived with bayonet lamp sockets and matching plugs and double adaptors, all of which can still be obtained, although no longer used for their original purpose.
I am fairly sure that the product in Figure 2 would not have been sold here though. Chances are it wouldn't have met local standards,even if it was made to suit our bayonet sockets.
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A valve a day keeps the transistor away...
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Location: Oradell, US
Member since 2 April 2010
Member #: 643
Postcount: 833
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More electrical history: Way back when, they also had combo outlets like this
Idea looks like being that one could use the same electrical circuit to power grounded equipment, or regular 2 prong plug equipped equipment. To get around the fact that the crawfoot 3 pin outlet didn't accept our parallel pin plugs.
More common were these:
Which I've used to power my Aussie radios here in the USA, feed the slanted pins with both phases of our 120VAC, to get 240V. These radios don't mind it being 60Hz, and because the radios use power transformers, they don't care that both lines are hot with 120V. Of course ground is earthed.  Clock radios would be a different issue, especially the older Telechron drive ones. Digital clocks can usually be reconfigured by grounding or ungrounding a pin on the clock chip.
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7444
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Which I've used to power my Aussie radios here in the USA, feed the slanted pins with both phases of our 120VAC, to get 240V. These radios don't mind it being 60Hz, and because the radios use power transformers, they don't care that both lines are hot with 120V.
This is how most 12v volt to 240 volt inverters are configured. In fact, if the neutral wire in our electrical system wasn't bonded to earth it'd be the same for that too.
A transformer designed for a given frequency will most often accept being run at higher frequencies but could overheat if subject to lower frequencies. You should be right with 60Hz. AWA made lots of radios for markets here that had 40Hz AC supplies and these should be fine too. Such radios had huge transformers in them and were often stencilled "40~" as the Hertz unit of measurement wasn't commonplace at the time.
It's amazing how many countries ended up adopting this pin pattern as its universal socket. Australia, New Zealand, Papua New Guinea, Nauru, China and Uraguay to name several. In Australia there's quite a few variations where pins take on new shapes or get larger. 15 amp sockets, 20 amp sockets, 25 amp sockets, 32 amp sockets, round earth pin for specialist lighting circuits and process heat (off-peak heat bank) tariffs, fourth pin above the angled pins for emergency lighting and a four pin plug with straight active and neutral pins also for emergency lighting. I'll see if I can do some drawings tonight.
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A valve a day keeps the transistor away...
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