Common causes of excessive current in the motor of the boiler's high-pressure feed pump
1. Operating under off-design conditions for head and flow values
1. Excessive head setting: If the head setting value of the boiler water supply pump is higher than the actual demand, the excess head energy will be converted into flow rate, resulting in an excessive flow rate, which in turn increases the energy consumption of the pump, raises the motor current, and in severe cases, may trigger the overload protection mechanism.
2. Flow over limit: When the actual flow rate of the pump exceeds its designed rated value, the motor needs to exert additional power to keep the pump running, resulting in the current exceeding the normal range.
II. Factors at the Level of the Entire Boiler System
1. Insufficient system backpressure establishment: During the initial operation or debugging phase of the system, if the backpressure is not properly established, and the pump outlet valves are opened rapidly or to a large extent, it may cause a sudden increase in flow rate, putting excessive load on the motor.
2. Variation in pipeline resistance: Changes in resistance caused by obstacles and sharp turns within the pipeline directly affect the pump's head and flow rate. A sudden decrease in resistance (such as when a valve opens completely in an instant) may temporarily increase the flow rate, leading to overload of the motor current.
III. Internal Factors of Pump Body and Motor
1. Pump shaft bending or bearing wear: These problems increase the friction during the operation of the pump. The motor needs to increase its output to overcome the resistance, and the current subsequently rises.
2. Excessive compression of the packing: An overly tight packing seal will increase the friction of the water pump, and also cause the motor current to rise.
3. Incorrect motor selection: If the motor power is insufficient to support the pump in its rated operation conditions, it is prone to current overload.
IV. Other Potential Factors
1. Gases entering the pump: When air enters the water pump, it will reduce the drainage efficiency, increase the operating resistance, impose additional burden on the motor, and potentially cause the current to exceed the limit.
2. Motor moisture: If the motor is exposed to a humid environment for a long time or is submerged in water, its insulation performance will be compromised, which may lead to current leakage or overload.
Countermeasures for Overload of Boiler High-Pressure Feed Pump Motor
1. Optimize the setting of head and flow rate: Adjust the pump's head and flow rate according to actual needs, ensuring they are compatible with the rated power of the motor.
2. Gradually establish system backpressure: During the initial stage of system commissioning and operation, the opening speed of the valves should be carefully controlled to gradually build up the system backpressure.
3. Strengthen maintenance of the pump body and motor: Regularly inspect the pump shaft, bearings, packing, etc., and replace worn parts in time. Keep the motor dry and clean, and maintain its insulation performance.
4. Upgrade motor configuration: In cases where the motor power is insufficient, replace it with a motor of greater power to ensure that the water pump operates stably under the rated conditions.
In conclusion, the reasons for the excessive current of the boiler high-pressure feed pump motor are complex and diverse. Comprehensive consideration is required and targeted measures should be taken to solve the problem.
