Machinery Lubrication

Machinery Lubrication Jan-Feb 2018

Machinery Lubrication magazine published by Noria Corporation

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14 | January - February 2018 | www . When a hydraulic issue occurs, the pump usually is one of the first components changed out, but it actually should be the last. Why? Because a pump is the most time-consuming part to replace and the most expensive. It should never be changed before several tests are conducted. e easiest tests and checks should be made first. Visual Tests Is the electric motor running? is sounds like a no-brainer, but it should not be overlooked. I was teaching a class at a plant in Kentucky a few years ago when a student came in one morning and said they had an overheating problem on the press the previous night. He said they changed the filtering and cooling pump to only find out later that the motor had been turned off. Is the pump shaft rotating? Many times this is difficult to tell because of coupling guards and C-face mounts. I know of one plant where the pressure at the pump outlet port was fluctuating. ey changed the pump and found that the worn key on the shaft had damaged the keyway on the coupling. Check the oil level. is also should be obvious, as it often is the only thing checked before the pump is changed. e oil level should be 3 inches above the pump suction. Otherwise, a vortex can form in the reservoir, allowing air into the pump. Troubleshooting Hydraulic Pumps HYDRAULICS Al Smiley | GPM Hydraulic Consulting Inlet line unrestricted - Full flow into pump suction port Inlet line restricted - Air is "pulled" out of hydraulic oil High vacuum pressure occurs when a pump does not receive adequate oil volume at its suction port.

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