How to test an electric motor

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The Basics of Motor Testing

how to test an electric motor

When an electric motor fails to start, runs intermittently, runs hot, or continually trips its overcurrent device, there my be a variety of causes.

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Knowledge of the basics together with powerful new test equipment vastly simplifies the job. Electric motors have had a reputation for being a mix of science and magic. So when a motor fails to operate it may not be obvious what the problem is. Knowing some basic methods and techniques along with having a few test instruments handy helps detect and diagnose problems with ease. When an electric motor fails to start, runs intermittently or hot, or continually trips its overcurrent device, there my be a variety of causes. Sometimes the trouble lies within the power supply, including branch circuit conductors or a motor controller. Another possibility is that the driven load is jammed, binding or mismatched.

When an electric motor fails to start, runs intermittently, runs hot, or continually trips its overcurrent device, there my be a variety of causes. Sometimes the trouble lies within the power supply, including branch circuit conductors or motor controller. Another possibility is that the driven load is jammed, binding or mismatched. If the motor itself has developed a fault, the fault may be a burnt wire or connection, a winding failure including insulation deterioration, or a deteriorating bearing. A number of diagnostic tools a clamp-on ammeter, temperature sensor, Megger, or oscilloscope may help illuminate the problem. Preliminary often definitive tests generally take place using the ubiquitous multimeter.

To measure the health of an electric motor, engineers must consider several key factors , including performance, energy use, operating costs, equipment durability, and overall system reliability. These are all integral components of motor health , which depends on regular monitoring and diagnostic testing. When evaluating the health of a motor, the following aspects should be carefully analyzed: alignment, ventilation, lubrication, consistency of operation, and heat output. Proper testing, therefore, is a crucial step in motor upkeep. Below are a couple of the most common motor tests available, which can allow for significant time and cost savings thereby reducing the need for maintenance, repairs, and extra labor.

The goal here is to describe the testing at a level above the physical attributes, such as temperature, pressure, force, and so on, but below the level of a final assembly inside of which the electric motor resides. This region is bounded by murky lines, but staying at this level enables tangible comments. A motor needs to be given electrical power to turn the motor. The rate at which a motor moves is dependent on the signal that drives the motor. Two major components are utilized: the motor controller and the motor drive. The former translates position, speed, or force acceleration or torque commands to the signal s needed to move the motor.



Basic motor testing with multimeters and ammeters

3 phase motor test

Electric Motor Testing

Electrical maintenance programs are designed to increase equipment promptness and uptime while decreasing capital operating cost. Electric Motor Testing is usually the first thing to be sacrificed when cutting back on operational expenses. But smart companies, understands that without proper maintenance programs, there is billions of dollars of lost revenue through increased motor repair costs, downtime, and waste in industrial and commercial companies. After bearing failure, electrical faults are the most common mode of motor failure, so in addition, a properly planned electrical testing scheme is important for making sure of the plant reliability. Many diagnostic tools, such as clamp-on ammeters, temperature sensors, a Megger or oscilloscope, can help illuminate these issues.

Show less When a motor fails, it is often difficult to see why it failed just by looking at it. A motor placed in storage may or may not work, regardless of its physical appearance. A quick check-out can be done with a simple ohm meter, but there's a lot more information to collect and weigh before actually putting it to use. At no time during the motor check out is power required. If it is connected - disconnect it before attempting the steps below. To check an electric motor to see why it failed, look at the outside for signs of debris that has been sucked into the motor windings, as well as broken mounting holes or feet, and darkened paint that could indicate excessive heat.

There are several types of single phase motors. What is however common to them all is that they have a Start Winding, a Run Winding, and a Common connection between them as shown below:. Testing of single phase motors is pretty easy if certain basic steps are followed. The objective of any AC motor test is to determine the health status of the motor. General Inspections For the single phase motor, do the following: 1 Check the appearance of the motor. Check for burnt, damage to body or cooling fan or shaft.

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2 thoughts on “How to test an electric motor

  1. by Miles Budimir, Senior Editor Testing electric motors doesn't have to be a mystery. Knowledge of the basics together with powerful new test.

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