Electric motors can increase equipment promptness and uptime while reducing operating costs. Of course, when cutting on operational costs, electric motor testing is the first thing to sacrifice. But companies need proper maintenance programs to avoid losing revenue. Loss of revenue happens when there are increased motor repair costs, downtime, and waste in industrial and commercial enterprises.
What is electric motor testing?
It refers to assessing a motor using computerised equipment or tools. You perform motor testing to disclose hidden issues and prevent unnecessary failure. For example, an electric motor evaluates static parameters like wire damage, electrical current leakage, and insulation. Also, it helps take care of other parameters such as temperature fluctuations, distortions, and balance. But mechanical motor testing includes looking at cracks of a motor rotor and lamination sheet makeup. Each motor applies alternating current (AC) or direct current (DC). However, the testing method depends on the design and application of the motor. Hence, organisations partner with electric motor companies t get the best results during the testing.
Why is Electric Motor Testing Done?
Electrical faults are the most common modes of motor failure. You can divide the faults into rotor and winding issues. So, it’s important to have a proper electrical testing scheme to ensure plant reliability. You can use diagnostic tools such as temperature sensors, Megger or clamp-on ammeters to diagnose these problems.
Winding issues occur due to insulation ageing, power surges, damaged wires, contamination, thermal overload, and other causes. These problems start as energy crossing an insulation fault such as moisture, which sets apart at least one turn. It creates stress and raises the temperature across the fault until the winding falls.
What are some of the winding faults?
The faults occur between:
- The coil in a phase
- turns in a coil
- coils in different phases
- A coil or phase and ground
Finding one of these faults will save your plant lots of hours of shutdown and money in savings.
Common Motor tests you can perform on electric motors.
There are various kinds of testing done on motors by electrical motor companies. They include:
Electric Motor Impulse Testing
These tests help you understand how an electrical system can withstand sudden overvoltage due to weather. It also applies in normal situations like when low or high voltage equipment changes operation or in case of high voltage variations.
Wound rotor electric motor testing:
Using a wound rotor enables you to separate the 3 basic components. They include the stator, rotor, and resistor bank to identify the main cause quicker. If any issues occur in the rotor circuit, it affects the stator. In contrast, any problems on the stator reflect on the rotor circuit.
Electric motor rotation testing:
It’s crucial to test for rotational direction before you connect a motor to its load. It helps avoid damaging the load or confusing the operator. Proper rotational testing is done using a phase rotation meter. For instance, when installing a three-phase motor, the meter will have 6 leads. Three will be on the lead side (motor side) and three on the line side (supply side).
Megger testing:
It’s the most popular method to test the insulation resistance of an electrical motor due to its simplicity. A megohmmeter can provide high DC voltage at a current capacity to test insulation strength. However, it’s advisable to use this test with other testing methods. It’s because it’s not capable of identifying all potential faults inside a motor winding.
Insulation resistance testing:
In electric motor insulation, temperature increases as resistance decreases. It’s referred to as a negative temperature coefficient. The reason to test the insulation is to ensure the insulation resistance of a de-energized motor that decreases when you start the motor. It’s not common for temperature to increase at the start as moisture evaporates from the rising temperature of the winding. Therefore, the test needs a temperature rectification to 104 degrees Fahrenheit (40 Celsius). This is one of the best ways to test a single phase motor.
What are the benefits of motor testing?
Saves cost: Motor testing gives a clear picture of the motor condition. As a result, it helps limit potential collateral damage due to failures and reduces maintenance costs. In addition, it helps identify the type of maintenance a motor requires, whether it needs replacement or if a critical decision is needed.
Conservation of energy: Motor current analysis helps identify conditions in a motor that causes increased power consumption. This can affect the motor’s overall power quality and speed asset wear and becomes costly due to energy consumption increase.
Increased uptime: Pointing out faulty motors before they fail ensures your system stays up and running. In addition, this makes it easier to do planned maintenance to correct the issues discovered.
Improved safety: Testing motors reduces the frequency and urgency of breakdowns. It gives the maintenance team more time to shift their attention to scheduled downtimes. Motor testing also can help detect faulty electrical connections, reducing the risk of a fire.
Generally, motor testing is vital in any plant. It will help identify problems that will reduce downtime, increase productivity, and conserve energy.
