Basic Wastewater Operator Practice Exam

What would most likely cause a submersible pump to have an AMP reading that is above the optimum level?

1. Nothing, pumps normally run high AMPs

2. Clogged impeller

3. Low voltage at power supply

4. Low flow to pump station

The correct answer is: Clogged impeller

A submersible pump typically shows an AMP reading that is indicative of its operational efficiency. When the AMP reading is above the optimum level, it often suggests that the pump is experiencing an abnormal condition. One common cause for this deviation is a clogged impeller. When the impeller, which is responsible for moving water through the pump, becomes obstructed by debris, sediment, or other materials, it puts additional strain on the motor. This obstruction makes it harder for the pump to perform its function, resulting in increased current draw to maintain the necessary flow and pressure. Consequently, this increase in current translates to a higher AMP reading, signaling that maintenance or intervention may be needed to resolve the clog and restore the pump to its normal operating level. The other options do relate to pump operation but do not directly explain the scenario of increased AMP readings as effectively as a clogged impeller does. For instance, while low voltage at the power supply can cause performance issues too, it would typically lower the pump's efficiency rather than raise the AMP reading. Similarly, low flow to the pump station and the premise that nothing is wrong are less likely explanations for an increase in the AMP reading compared to the well-established relationship between pump blockages and motor strain.