[GreenKeys] 2 1/2A SCREW IN FUSE

[Bruce Gentry]

Power voltages in the USA have risen over the past 50-60 years. In the 
first half of the twentieth century, 110/220 volts was standard for 
residential and small business DC, so AC was the same so light bulbs and 
universal motors could be used on either.  With the widespread 
installation of and conversion to three phase in the 1950s, 120/208 
volts four wire became the standard in medium and large buildings. Later 
appliances and bulbs were rated for 120 so they could be used in 
apartment buildings, and single phase service was raised so motors would 
not be run undervoltage and the bulbs would be bright. Unfortunately, 
many window air conditioners rated for 240 were plugged into 208, and 
the compressor motors overheated to early destruction unless an auto 
transformer to raise it to 240 was used. The transformers were once very 
easy to find at junk stores when  208 volt air conditioners became  
available.  I measured about 232 give or take a little in England and 
Israel within the past few years.

       Bruce Gentry

On 8/12/17 6:57 PM, Dave Horsfall wrote:
> On Sat, 12 Aug 2017, Bruce Gentry wrote:
>
>> If the synchronous motors are designed for 110 or 115 volts at 60 
>> cycles, the common 120-125 seen today in many places can certainly 
>> cause over current and overheating.
>
> That's interesting; I've always assumed that USA was 110-115v; is it 
> now actually 120-125v, or nominally so?
>
> Trivia: Australia is officially 230v in line with Europe, yet I still 
> regularly measure 240v or so (which is within tolerance). And at one 
> time, Western Australia was 250v, until they joined the national grid...
>