Question about Danfoss Sundstrand-sauer-danfoss Sundstrand Hydraulic Pump

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Should you have charge pump pressure when unit is engaged 25-2012model 12-xd-31981 ser. what should charge pump pressure be

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Anytime the pump is running, there should be charge pump pressure present. When the pump is in nuetral, the hot oil shuttle will usually block flow, so the the charge pump builds up pressure untill the charge pump relief opens up, the pressure setting this occurs at depends on the what the OEM wanted. When the pump strokes up, there is a pressure differential between the two work ports, which shifts the hot oil shuttle spool, allowing oil to flow across the hot oil shuttle relief valve which will have a lower setting than the charge pump relief. So in Nuetral you will generally have a higher charge pump pressure and when on stroke, you will see charge pump pressure drop 50 to 100 psi.
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Posted on Mar 15, 2009



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2 Answers

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1 Answer

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