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Topics - scott p

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Generators / A hypothetical generator application
« on: December 26, 2019, 05:29:50 PM »
 
Two AC generators, one 25000 watt 104 amp at 220 volts and one 6500 watt 30 amp at 220 volt, diesel powered with mechanical governors.
Both generators altered to DC through appropriate heavy-duty high PIV diodes.
One 30 hp DC motor, 220 volt, separately excited, 100 amp draw fully loaded. Draw at no load unknown.
The generators are paralleled to produce 134 amps at 220 volt DC.
1.   The major generator is variable speed so as to idle in no load situations.
2.   The minor generator is set to constant speed.
The theory
The minor generator is set to 220 volts thereabouts (perhaps slightly over) via the governor. The major generator is set to 220 volt via the governor when pulled up to full speed.
When a full load is coming on the major generator is brought up to speed. When the load hits, the minor generator will droop and fall back to 220 volts thereby allowing the major generator to share the load.
When paralleled, because of the PIV of the diodes the generators cannot catastrophically interfere with each other in the usual ways as when paralleling straight DC or straight AC generators. 
QUESTIONS
Under normal paralleling operations the two generators will lock up and become one as long as both are producing. Will these two hypothetical generators have a tendency to lockup in spite of the diodes??
Will a 100-amp normally AC circuit breaker work under these DC conditions??
Two mechanical governors might be a problem??

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Engines / Lister SL1
« on: August 27, 2019, 07:31:03 PM »
Looking to rebuild a Lister SL1. I sent the crank off to the shop. They say the crank is off  by .002.  They couldn't find the tolerance limit for this engine and suggested that being off that much would kill the oil pressure. I wonder if with a new bearing that .002 would be acceptable.as far as the  oil pressure is concerned.

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Engines / HR2
« on: October 29, 2018, 06:36:49 PM »
Any body familiar with these engines? Finishing a rebuild and have it setup as  per the manual. Will run at 1800 rpm until loaded then the rpm falls off on account the pump rack coming up against the overload trip.

The spill is correct. The fuel pump and governor settings are correct to the last step,which is setting engine load.

This involves turning the overload stop downwards or upwards for various speeds. Not sure what they mean by that.

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