"RichardS" noaccess@invalid wrote in message
. ..
"IMM" wrote in message
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"G&M" wrote in message
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"Andy Hall" wrote in message
...
On 7 Jun 2004 17:53:55 -0700, (cisco
kid)
wrote:

Hi All - My problems with power tools is that the manufacturers
seems
to have redefined the enginnering term power and do not quote
torque
or impact values very often. I mean brake horse power - which I
believe should mean the actual delivered power at the tool bit when
when all the other losses such as bad internal design limitations,
gearing, friction etc have been taken into account. So if my Bosch
is
delivering 500 watts bhp then with the same drill piece it should
be
worse than a 1000 watt NU tool. Of course it is'nt!! So maybe the
trades description boys should get in here. Or redefine a proper
unit
of power tool measurement.

I completely agree. Input power is largely irrelevant, with motors
ranging from good and decent in quality tools to diabolical at the
bottom end.

It's relatively easy to measure input power and can also mean that
seemingly impressive specs can be written. The Precision
Performance
Power Pro (or whatever they are called this week) routers from B&Q
are
the epitome of this, with a 2000W input power (allegedly) but with a
performance equivalent to about half that at best.


It is a legal requirement to quote input power for electrical items
and
it
may just be that the manufacturers don't want to confuse everybody too
much.

Input power? ENERGY in input, and POWER is outputted.

You pay for kW-hr of electricity (ENERGY), yet the electric fire is
rated
in
kW (POWER)
A boiler uses 50,000 BTUs of ENERGY and outputs BTU/hr (POWER) The
boiler
may output 25,000 BTU/hr, hence making it 50% efficient.

Don't confuse energy and power.


Excellent.

So, perhaps a 1000W diy tool rated for 3 hours continuous use should be
sold
as a 10.8MJ tool, whereas a 1000W industrial tool rated for 10 hours
continuous use would be sold as a 36MJ tool?

That'd help (confuse).

Mo more helpful or confusing than it already is.