View Single Post
  #16   Report Post  
Posted to alt.home.repair
Smarty Smarty is offline
external usenet poster
 
Posts: 625
Default Will a 1kw genny start my fridge *update*

Tony,

Peak to peak means one thing and "peak" means another. "Peak" music power as
mis-used by stereo salesmen (until the FTC forced the industry to adopt
correct and standardized terms) was a term used to exaggerate the true
average/RMS power which an amplifier could deliver. This has absolutely
nothing whatsoever to do with "peak to peak", the term you originally
mis-used.

Peak-to-peak, as the reference in Wikipedia correct states, merely indicates
the size of a waveform from its lowest (negative) peak to its highest
(positive) peak. If you have a scope in front of you, looking at a waveform,
the peak to peak voltage is nothing more than the height of the signal in
volts.

Generators make electricity, and one could describe the waveform they
produce by saying it has a peak to peak voltage of 336 volts (assuming a
sine wave and 120 volt RMS generator) but this is not a description of the
surge capacity of the generator.

When specifying / characterizing the ability of a generator to provide
transient, brief additional power, the term which electricians and
electrical engineers use is "peak" or "surge" or "transient", but never
"peak to peak". It may seem or sound similar, but is not the same thing.

Smarty



"Tony Hwang" wrote in message
news:7_2ci.21342$NV3.15737@pd7urf2no...
Smarty wrote:

There is no such thing as "peak-to-peak" ratings for a generator measured
in "fractional seconds".

You might be thinking of "peak", "surge", "maximum inrush" or other such
terms which describe the brief maximum current which the generator (and
its' associated fuse/breaker) can deliver.

"Peak-to-peak" is used in electrical engineering to describe the
amplitude / height of an analog waveform when measuring from the maximum
negative to positive swing. For a sine wave (the most common form of
alternating current), it represents a value which is about 2.8 times the
average / RMS value.

http://en.wikipedia.org/wiki/Peak-to-peak

Smarty


"Tony Hwang" wrote in message
news:HWTbi.21076$1i1.8301@pd7urf3no...

Toller wrote:

A month or two go I asked here if a Yamaha EF1000, which will produce
8a, will start my refrigerator that draws 13a at startup.
The majority opinion was probably; the fridge probably doesn't need 13a
to start and the genny will probably produce more than 8a for a short
time; so between the two...

As it happens, one retailer claimed that Yamaha told them the EF1000
will produce 3500w for 3 seconds, which is not supported on the Yamaha
website. I called Yamaha and was told that their website says it will
produce 1000w, so that is all it will produce. Eventually I got to the
supervisor's supervisor, who said that it will do 3500w, but they are
not making that claim anymore. (presumably they got complaints from
people who didn't understand what "3 seconds" meant.)

So I bought the EF1000. It will actually start my shopvac, which draws
16a at startup. I haven't pushed it any harder, so I can't actually
verify the 3500w, but it is good enough.
Alls well that ends well.

Incidentally, Honda told me the absolute max on their EU1000 is 1000w
and it will not start my fridge; I don't know if someone higher up would
say otherwise.

Hi,
If you think in terms of peak to peak rating. But that is measured is
fractional seconds.




Hi,
You just explained what I said in plain language.
Yup, peak to peak, average, rms three terms commonly used.
Remember stereo salesman used to use peak music power to sell El Cheapo
amps? Kikewise! Marketing gimmicks are many and confusing to gemeral
consumers.