Closed center system... oil circulation stops when there's no demand... pump "goes out of stroke" and pumps only enough oil to keep system at "standby pressure" saving power and reducing heat.
The way it was taught to me in JD tech school. When pressure stabilizes above set stand-by pressure(2250 psi is factory setting),trapped oil in crankcase of hyd pump(caused by stroke control valve closing) forces pistons away from pump crankshaft causing no oil to be pumped and psi is trapped in lines. When crankcase pressure drops pistons are pushed by springs back against turning crankshaft and pumping commences.
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Today's Featured Article - A City Guy's First Tractor - by Fred Hambrecht. After living in apartments in Atlanta for more years than I care to remember, the wife and I decided to move to the country. Humming "Green Acres is the place for me..." we purchased a 29 acre tract about 60 miles south of Atlanta. Next came the house, I could talk about that ordeal for another two weeks... But, I want to talk about my tractor! We didn't even own a lawnmower, and all of a sudden we had enough grass to feed all the starving children of the bovine world. Naturally, I talked
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