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Ken Heaton & Anne Tobin
 
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Default On-board generators

Comments below:

"Chris Newport" wrote in message
news:3120722.S4CdkZmr6U@callisto...
On Thursday 27 May 2004 7:26 pm in rec.boats.cruising Jeff Morris wrote:

I have a follow-on question:
What will happen if I hook a Honda EU1000 to a Heart 2000 charger, which
would
like to charge at 100 Amps? Will it settle at some compromise charge
rate, or will it roll over and die?


100 amps at 12 volts is 1200 watts, but add some ineffiency and the load
will probably be about 1400 watts. This type of overload is nasty - it is
too small to blow a fuse or trip a breaker.

What happens will depend on the actual available power of the engine.
If the engine is only just good enough for 1000 watts it will slow down
and may eventually stall, but it will almost certainly overheat.

If the engine has power in reserve the generator becomes the weak point.
Once again a sustained overload will cause overheating, in this case
the enamel insulation in the windings will be damaged causing internal
shorts. This leads to the escape of the magic smoke, requiring expensive
repairs or consignment to the rubbish heap.


First I'd better say I don't know what will happen to the Honda if you
overload it, probably trip a breaker, but I thought you might be interested
to know the Honda EU1000 isn't a normal genset. The Honda EU1000 uses a gas
powered motor to drive an alternator (AC generator) like all gensets. All
normal gensets run at a constant speed if they have any connected load, with
a governor trying to maintain that speed as the electrical load changes.
This is necessary so that the genset produces 60 Hz because the frequency of
the AC is dependant on generator speed. But, in the Honda, the AC power
produced is then rectified to DC and then run through a true sine wave
inverter to produce 60 Hz AC. The motor in the Honda can run at any speed
it wants to match the load as the frequency is set at the inverter. That's
why the Honda can still be producing AC (though less of it) when the genset
is running just above idle speed. Neat rig.

Ken H.