Re: Generator Cart

[Scott Hull <ScottHull@compuserve.com>]

Grant Wallace wrote:

>HP= Torque X Speed

>To double HP you may either double the torque or the RPM.

>Doubling torque doubles the stress on the engine.

>Doubling RPM quadruples the stress on the engine.

Increasing the HP by increasing torque or RPM causes different areas to be
stressed. If you increase the combustion pressure to increase torque for
more HP at a given RPM, you could blow the head gasket for instance. If you
keep pressure the same but double the RPM to get more HP, there is no
increase in stress caused by combustion but you could throw a rod if it
can't handle the increased stress resulting from trying to accelerate and
deccelerate the piston at twice the normal rate.

It depends on the design of the engine. Some can withstand increased
pressure (high compression or turbocharge or supercharge) while some can
withstand higher RPM. Most of the industrial engines used on generators
cannot reliably produce double the power without structural modifications.
Inreasing the RPM a little is usually just a matter of adjusting the
governor so it is the easiest thing to do.

It's similar to electric motors. Some can withstand higher current
(torque). Others can't, while higher voltage (RPM) might not cause a
problem. If the current (torque) is too high, it burns up, if the voltage
(RPM) is too high, it flies apart.

SAH