Maximizing Your Electric Motor Replacement

March 22, 2023

An electric motor operated correctly can provide excellent and reliable service for many years, sometimes up to several decades. When it fails, you have to quickly find and install a motor replacement as fast as possible to reduce the impact on your productivity. But what if you had already chosen the ideal replacement – one that not only does the job but provides better efficiency and saves you money?

Why Choose an Electric Motor Replacement Now?

It can take quite a bit of time and attention to match your old motor's characteristics to brand new replacement options. Even when your current motor is still running, it's essential to go through the steps for selecting a replacement that will perform flawlessly at your site. This enables you to purchase a new one beforehand and have it ready to go or to have the information you need on hand when a breakdown occurs.

As you'll see throughout the rest of the article, there are several key motor characteristics you must pay attention to that have the potential to save you a lot of money. You may even want to replace your motor now to take advantage of them.

A Word on Motor Energy Efficiency

Electric motors use a lot of power. According to some estimates, applications driven by electric motors account for up to half of worldwide electricity consumption, making efficiency a prime factor in reducing your operating costs and meeting energy efficiency regulations in your area.

Higher efficiency motors typically cost more, as they usually have a more complex design that utilizes higher-quality manufacturing processes and materials. But the purchase price is not the whole story. Over a 10-year lifespan, a high duty cycle motor's purchase price may account for only a small percent of the total cost of ownership. This makes it even more important to know your most efficient options so that your next motor will optimize your expenses in the long term.

Governments and regulating bodies have been rapidly developing MEPS (Minimum Energy Performance Standards) that impact all kinds of applications that use electric motors. Besides what is required by law, these standards are backed by various types of financial rebates and incentives from which you may benefit.

Finding a Replacement Motor and What to Look For

Matching Nameplate Information

When searching for a replacement motor, the first thing is to look at the motor nameplate and any additional documentation provided by the manufacturer or supplier. The type of information on a nameplate is defined by NEMA standards (in North America) and IEC standards (in Europe and the rest of the world). Although these standards are not the same, they share most key information. They can be matched to one another with a basic understanding of their respective letters and codes.

The nameplate offers the most critical information about the motor, including the type, speed and torque characteristics, service factor and more. When selecting a new motor, the easiest approach is simply using the nameplate information to find a good match if the previous one performed well.

To speed up this process, you can leverage the eMotors cross-reference tool within each product listing, which will automatically suggest motor replacement options when you type in your current model. This tool matches every detail about your current motor with our extensive product database to find the very best choice and save you time and effort.

Suppose your old motor still works and you have some time. In that case, it may be of great benefit to you to make a thorough assessment of the ideal performance characteristics you need from a new motor, especially during start-up, so that it can better match the requirements of your application. This can save you in maintenance bills and reduce your operational costs.

Speed Control

If your application requires speed control of the motor, you will need to find a replacement that offers this capability. Most motors can be speed controlled, but different motor designs have tradeoffs in the controllers' cost and performance. You may be able to use your current speed controller if a new motor is compatible.

Speed controllers come with a range of performance characteristics. Typical VFDs (Variable Frequency Drives) used with AC motors provide a marginal level of control around the base RPM. In contrast, Vector Control VFDs can give reasonable control over the entire speed range. For exact control, especially at low speeds, a DC motor and speed controller is usually the best option. Evaluate your requirements so that your new motor gives you the speed control you need.

If your motor starts under load, equipping it with a soft starter is a great way to ramp up the motor speed slowly, preventing shock loads and damaging inrush currents that can overheat your motor and reduce its service life.

Check Your Connections

Different types of motors have different power supply requirements and connection types. DC motors require a DC power controller, and AC motors require either a single-phase or three-phase AC supply. You will need to know which kind of power you have available to determine what type of motor will fit in.

Standard three-phase AC motors use three connections, but larger motors may have a star-delta connection type that requires six connections instead of the standard three. This allows the motor to start up under less power and reduces the stress on the windings and the load. Ensure you have these connections available if you would like to purchase a star-delta motor as a replacement.

Motor Mounting

When selecting a new motor, make sure that it will fit in the required space and that it is compatible with the mounting configuration you have available. Some applications are compact and have strict requirements, while others may offer some leg room as to the motor's possible dimensions and how it may be positioned.

It's essential to check how the motor will connect to the gearbox or driven load so that the shaft size is not too big or small, and it can easily fit into the current configuration.

Motor Enclosure Type

When a motor operates in an unsheltered or polluted environment, you should try to attempt to prevent contaminants such as dirt and water from entering inside and damaging the windings and internal components.

If the motor is kept indoors in a clean, dry, climate-controlled environment, an ODP (Open Drip Proof) enclosure may be sufficient, but motors operated outdoors or in dusty and dirty environments will fare much better with a TEFC (Totally Enclosed Fan Cooled) enclosure type.

There is a range of motor enclosure types with different tradeoffs in protection and cooling. Some are mandated by law in specific applications (such as explosion-proof enclosures in the petroleum industry and washdown enclosures in food processing). Ensure you know what type of enclosure you need to maximize your motor's service life and protect your infrastructure and personnel.


This is a brief overview of the steps you need to take and what you need to focus on when selecting a new motor to replace your legacy one. Take a look at the motors we can offer to you that will improve your productivity and minimize your costs and get in touch with one of our experienced engineers to find out more.

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