What Failures Affect Electric Pumps and How to Prevent Them?

Electric pumps are essential in a wide range of applications. However, their operation is exposed to conditions that can cause serious damage if not detected in time. In this article, we cover the most common failures that affect these systems and why it’s critical to have proper protection to prevent them.

The Most Common Failures in Electric Pumps (Including Submersible Pumps)

Pumps operate under variable conditions that, if left unchecked, can severely damage the motor and lead to unexpected shutdowns. These are some of the most frequent failures:

• Overload: Occurs when the motor runs above its rated capacity for an extended period, causing overheating and potential internal damage.
• Dry run or underload: Happens when the pump runs without water, due to an empty tank or a closed valve. This causes heat and friction without fluid, which accelerates mechanical wear and quickly damages the pump.
• Rapid cycling: Frequent start-stop cycles caused by pressure fluctuations or control issues can damage the pump. Motors have a limit on how many starts per hour they can handle, and each start generates heat. If not enough time is allowed for this heat to dissipate, damage can occur.
• Phase loss (in three-phase systems): The loss of one phase causes imbalance, torque loss, and immediate risk of motor failure.
• Overvoltage or undervoltage: Variations in supply voltage directly affect motor performance, shortening its lifespan or even causing immediate failure.
• Seal leakage: In submersible pumps, a leak in the mechanical seal allows water to enter and mix with the motor oil. This moisture can cause insulation failure and damage the motor if not detected in time.
• Overtemperature: Motor overheating, caused by excessive workload or cooling system failures, can result in serious damage if the pump isn’t disconnected promptly.

Why Is It Important to Protect a Pump?

A pump operating without proper protection is vulnerable to failures that can cause anything from unexpected shutdowns to irreversible damage. In industrial, commercial, and even residential applications, a pump failure can lead to financial losses, service interruptions, or collateral damage to other equipment.

Traditional protection using thermal overload relays or basic circuit breakers is often limited—they don’t detect all critical operating conditions in real time, nor do they prevent situations like dry run without additional sensors.

Conclusion and Available Solutions

Having a reliable protection system for electric pumps is not a luxury—it’s a necessity. Early detection of overload, dry run, voltage anomalies, phase loss, seal leakage, and overheating allows you to intervene before serious damage occurs. This results in greater safety, less corrective maintenance, and more operational uptime.

At Nassar Electronics, we offer a line of specialized protection devices that comprehensively safeguard your pumping systems:

• The Pump Monitor is a smart protection device that monitors the motor’s electrical behavior in real time. It detects faults such as overload, underload (dry run), rapid cycling, voltage anomalies, and—on the three-phase version—phase loss. The single-phase version is self-calibrating and also protects against overvoltage and undervoltage. Both models feature an LCD screen, fault memory, and are easy to configure.
  • Pump Monitor PM‑2: For single-phase pumps from ¼ to 15 HP. Self-calibrating.
    Learn more about the Pump Monitor PM‑2 for single-phase pumps
  • Pump Monitor PM‑3: For three-phase pumps from 1 to 300 HP.
    Learn more about the Pump Monitor PM‑3 for three-phase pumps
• The Seal Leakage and Overtemperature Detector DFS‑12 is designed for submersible pumps equipped with internal humidity and temperature sensors. This device monitors seal integrity and motor temperature, automatically disconnecting the pump if moisture or overheating is detected. It features adjustable sensitivity, fault memory, and manual or automatic reset options. Compatible with pumps of any size.
  Learn more about the DFS‑12 Detector for submersible pumps