Taking into account the type of equipment, installation method and driving method (rigid connection, belt drive, gear drive, etc.), it is not specifically designed to establish standards for overhaul or newly installed equipment, but is used to evaluate the entire status of installed or operating equipment. Through these, a state maintenance plan can be established. Although there is a lack of experience and historical data, this table will still effectively guide the implementation of the maintenance plan.

Things to note

The equipment speed is between 500rpm and 600000rpm;

The measurement points of bearing vibration speed and acceleration are as close as possible to the bearing requirements;

The equipment is not equipped with a vibration isolation device (for equipment with a vibration isolation device installed, the alarm value must be increased by 30% ~ 50%);

The alarm values set for the motor are also applicable to other special equipment, unless otherwise specified;

The alarm value set for the independent external gearbox is higher than 25% for other special equipment.

Smooth:

The frequency vibration speed of the equipment is within a safe range, and only regular (weekly, monthly, etc.) inspections are needed to determine whether the vibration has increased significantly. At this time, spectrum analysis should be performed on these devices to establish the baseline spectrum characteristics of the equipment under normal conditions. This information has no practical value for faults in the incubation period.

Alarm:

In the absence of historical records, the warning area given in the table is the actual starting point for the start of the predictive maintenance plan. When the equipment is in this state, a comprehensive analysis must be carried out to find the cause of the vibration, and it must be shut down for maintenance as soon as possible according to the plan.

Before scheduled downtime for maintenance, equipment vibration should be checked much more frequently than under normal conditions. Especially for key equipment that is running in the factory, vibration inspections must be carried out every day to prevent catastrophic accidents. A vibration expert once said: "Once the condition of the equipment starts to deteriorate, it will deteriorate rapidly."

When the vibration speed value of the equipment exceeds the alarm value, a comprehensive analysis should be conducted to determine the cause of the failure and consideration should be given to shutting down the equipment directly for repairs. Lessons have taught us that if equipment continues to operate at such a high vibration level, the end result will be a catastrophic accident, causing heavy losses. Although some equipment may still operate beyond the limit under the instruction of a few people, this is a risky behavior.

For equipment that is not within the above range, the following table can provide the corresponding vibration evaluation method.

Speed standard for frequency vibration intensity

It is impossible to establish an absolute vibration standard. In other words, there is no absolutely accurate vibration limit that demarcates normal operation and emergency shutdown. The purpose of predictive maintenance is to detect problems so that faults can be identified and eliminated before an accident occurs, rather than to see how much vibration the equipment can tolerate before a fault occurs.

Source: Pump Steward

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