Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/1005929
18 | July - August 2018 | www . machinerylubrication.com HYDRAULICS a loose wire was found in the cabinet. e intermittent stopping of the motor was a volume problem. When the power supply voltage dropped below the acceptable level, the pump was de-stroked to a zero flow output. 2. Gather Information Once you've identified the type of problem, the next step is to gather information. More than likely when you arrive at the problematic hydraulic system, some things have already been done. Have any pressure or electrical adjustments been made? Have any hydraulic components been changed out? If so, do the new components have the exact part number as the components that were replaced? One number or letter difference in the part number may mean that the valve will not work in the system. Several years ago, a positioning problem was identi- fied on an oriented strand-board press in Georgia. e position of the platen was controlled at four different points with linear-displacement transducers. e pressure in the ram that controlled one of the corner rams was fluctuating excessively. After 11 hours, it was determined that the replacement position-control valve had one letter different than the original valve. Once the correct valve was installed, the press operated normally. Visual checks must be made during this process to assess the oil level, filter condition, leakage, pump coupling condition, etc. Also, ask for the latest oil anal- ysis report to verify the oil's cleanliness level. I was recently called to troubleshoot an issue at an automotive plant where five pumps had been changed in 24 hours. When I arrived, I asked if anything had been done prior to the repeated failure of the pumps. e supervisor said that a hose failed in the system and that the reservoir was refilled with fluid during the shift change. Shortly after that, the issues with the pumps started. After inspecting the system, I did not see a breather cap on the reservoir. Apparently, when the first-shift oiler refilled the tank, he did so by removing the breather cap. Once filling was completed, the second-shift oiler installed a pipe plug on the threads where the breather was originally mounted. Now there was no place for air to enter the reservoir, which resulted in the failure of the pumps. Machine operators can provide some of the best information as to what is occurring. While main- tenance workers may only show up when a machine Reading a hydraulic schematic can identify a problem before the first part is replaced. A blown fuse on a solenoid-operated valve resulted in unnecessary downtime at a plant in Arkansas. START YOUR FREE SUBSCRIPTION www.machinerylubrication.com