Another failure that you sometimes see or condition that you can see in the pump is related to the bearings running hot. In this particular condition, the pump is operating again, the valves are open. In this scenario, the flow and the system are near the rated point and so there’s no apparent hydraulic performance issue, but in fact, the bearing temperature is higher than desired. This is causing the bearings to run hot.
The first thing you’re going to want to look at here is improper alignment because if you’ve got a misalignment happening between the pump and the motor you can see excessive vibration and also loading on the bearings and this can cause the bearing temperatures to be higher or elevated. In this case, we’re going to check your alignment between your pump and your driver. You can also have improper lubrication and many pumps have an oil sump. We need to make sure that the correct oil is being used, and that the oil level is at the correct height. Make sure that the bearings are getting proper lubrication. One of the characteristics of an oil that you need to be what you need to watch out for is the oil needs to be non-foaming oil or lubricant. In some cases, the oil can generate a foam and if that happens then the lubrication is not directly lubricating the bearings. You have to have the right lubricant at the right level. Most pumps are going to have a sight glass or some other means to determine the appropriate lubricant level.
Finally, in some situations, this is typically an elevated service you may need to have a bearing cooler. These are for a typical ANSI pump or a Griswold pump. If you’re operating a system at over 250 degrees Fahrenheit then you may need to have a bearing cooler because the fluid temperature is elevated enough that it will actually increase the temperature at the bearings and bearings do need to remain cool. In this case, you may need to install a bearing cooler and those typically a power frame has the opportunity or is designed in a way that a bearing cooler can be added. This means you also have to make sure that the cooling water lines are operating as expected. They provide the correct cooling to the bearings.
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