Since the invention of the AC electric motor, motor manufacturers have been innovating to make the motor more resilient, more capable, and more energy efficient. Some industries have benefitted from these innovations more than others, especially where a standard efficiency motor just doesn’t quite cut it. Heavy, harsh, contaminated, severe-duty environments need higher reliability and better efficiency from their electric motors.
Industries like Oil & Gas, Chemical, and Pulp & Paper, face the problem of excessive unplanned downtime due to early motor failures. That is, until the release of the IEEE-841 motor standards in 1986.
Who is IEEE?
The Institute of Electrical and Electronic Engineers (or IEEE) is the world’s largest technical professional society. It leads the development of industrial standards for telecommunication, electric power, and consumer electronics.
History of IEEE
Though electricity had technically been around for a while already, it wasn’t widely adopted by society until the late 1800s. And in 1884, in the state of New York, the IEEE was founded to encourage the innovation and development of electrical products and components. The early leaders of the professional organization include some major names like Thomas Edison and Alexander Graham Bell.
The membership of IEEE consists of Engineers and Scientists at its core, however, it also encompasses Computer Scientists, Software Developers, IT Professionals, Physicists, and even Medical Doctors.
Now, in 2021, the organization has a portfolio of almost 1200 electrical standards for various industries, with many more currently under development. Included in these standards is the IEEE-841 standard.
What is IEEE-841?
The IEEE-841 standard was developed in 1986 for the continuous and severe-duty operations of the Petroleum and Chemical industries. The environments and processes found within this industry place great mechanical stress on equipment and are often full of contaminants like dirt, dust, water, ice, etc. A standard efficiency electric motor will fail long before its expected lifespan due to stress and contamination, with bearing failure due to lubricant contamination being the number one cause.
The goal of the IEEE-841 motor standard was created to improve the reliability, efficiency, and performance of severe duty motors in this industry, effectively helping to prolong the life of the motors and decrease unwanted and costly downtime.
The standard has now been widely adopted by other industries, such as Pulp & Paper, and has been globally accepted for electric motors used in the most extreme conditions.
What Type of Motors Does IEEE-841 Cover?
The IEEE-841 electric motor standard covers “premium-efficiency totally enclosed fan-cooled (TEFC) and totally enclosed nonventilated (TENV), horizontal and vertical, single-speed, squirrel cage polyphase induction motors, 0.75 kW to 370 kW (1 hp to 500 hp), and up to 4000 V nominal, in National Electrical Manufacturers Association (NEMA) frame sizes 143T and larger, for petroleum, chemical, and other severe-duty applications (commonly referred to as premium-efficiency severe-duty motors).” (https://standards.ieee.org/standard/841-2021.html) However, it does exclude sleeve bearings and some additional features which are specific to explosion-proof electric motors.
No matter the manufacturer, every single motor advertised as IEEE-841 must meet the specs set out by the standard, with many of them featuring designs and testing that goes above and beyond what is set out by the standard. Additionally, there is a standardization of motor sizes across manufacturers. This allows for easy interchangeability which is convenient when you have difficulties sourcing a certain brand.
As of the most recent update published on May 28th, 2021, these are the most notable specifications set out by the IEEE-841 standard:
- Service conditions must be:
- -25°C to 40°C ambient temperature
- A maximum altitude of up to 1000m
- Humid, corrosive, or salty environments
- Full voltage starting
- Class I Division II hazardous locations
- Standard 5-year warranty
- Totally enclosed fan cooled (TEFC) or totally enclosed non ventilated (TENV) enclosure
- IP55 protection rating
- NEMA Design B torque and current characteristics and starting capabilities
- A minimum of a Class F insulation system
- Not to exceed a service factor of 1.0
- Allows for long-term reliability
- A short-term overload of no more than 15% is still allowed
- Stainless steel nameplate
- Specialized bearings
- Inner bearing cap
- L-10 lifespan
- Cast iron frames, end shields, fan covers, and terminal boxes (corrosion resistant)
- Specified efficiency ratings based on motor size/guaranteed minimum efficiency
- Improved seals
- Corrosion-resistant paint and internals such as stator, rotor, and shaft surfaces
- Reduced system vibration (.08 ips)
- Non-sparking fan
- Must contact the manufacturer when pairing with a speed drive – issues with harmonics and voltage spikes
It’s important to note that even if the motor meets and exceeds these specifications, regular maintenance is required to meet the premium efficiency standards.
The Dollars and Cents of It
When searching for your IEEE-841 electric motor, you may find that the initial purchase cost is higher than that of a similar motor at standard efficiency. So, why invest? When switching to IEEE-841 motors, there is an up to 50% decrease in early motor failures. This equals cost savings due to less unplanned downtime, spoiled product, and wasted employee resources. Less maintenance budget will be directed to motor repair and replacement costs. And an increase in power efficiency equals large cost savings on power consumption over the motor’s lifetime.
So, should you consider an IEEE-841 electric motor for your application? If your electric motors will be operating in harsh and contaminated environments and placed under significant mechanical stress, then yes, you should. You’ll benefit from reduced downtime, increased reliability, low noise levels, and high efficiency, all resulting in cost savings for your business.