You’ll notice that an IEC metric motor nameplate looks different than a NEMA nameplate. We’ve outlined how to read an IEC motor nameplate below. This article also includes considerations for:
- IEC Duty Cycle
- Metric Motor Frame Sizes
- Mounting Types
- ATEX Certification
- Connection Box Orientation
- How to Cross Reference an IEC Motor to a NEMA Motor
What is an IEC Motor
IEC metric motors are used around the world whereas NEMA motors are primarily used within North America. IEC (International Electrotechnical Commission) motors leverage the metric system whereas NEMA (National Electrical Manufacturers Assocation) motors use the imperial system. The functionality of these motors is comparable however, the measurements are different. If a machine is built with an IEC motor, typically, only an IEC motor will be a suitable drop-in replacement.
For a full overview of the difference between IEC and NEMA, check out our article here.
IEC Motor Nameplate
You may not see all these specifications on an IEC metric motor nameplate. The manufacturer data package should include the full details of the motor.
- Model Number or Product ID: This may be indicated as ‘type’ on the nameplate. This is the number you’ll use to find a replacement.
- Serial Number: This number is unique to your motor and can be used by the manufacturer to locate the motor in their database.
- Output Mechanical Power: NEMA motors will indicate ‘Horsepower’ or ‘HP’, whereas IEC motors will typically indicate ‘kW’. (1 horsepower = 0.74 KW). kW is more commonly used around the world.
- Line Voltage: this is indicated with a ‘V’.
- Full Load Current: this will be denoted with an ‘A’.
- Power Supply Frequency: this will be denoted with ‘Hz’.
- Power Factor at Full Load: this will be denoted as ‘cos’. This is an expression of energy efficiency and is often expressed as a percentage.
- RPM: this will be denoted as ‘RPM’, which indicates how many times the shaft will turn per minute.
- Insulation Class: this describes the ability of the motor windings to handle heat. This impacts the motor insulation lifetime. There are four classes for insulation factor. We typically deal with F and H.
|Class||Max Ambient Temp (°C)||Max Temp Rise (°C)||Hot-Spot Over Temp (°C)||Max Winding Temp (Tmax) (°C)|
- Ingress Protection: this is denoted as ‘IP’. The first number indicates the ability to protect against solids entering and the second number indicates the ability to protect against liquids entering. Check out our article on IP ratings for all the details.
- Motor weight: This will be indicated in kilograms and denoted as ‘kg’.
- International Efficiency Classes: this will be denoted as IE1, IE2, IE3, or IE4 and is a classification system to determine the minim energy performance standards (MEPS). Each government will indicate their MEPS. The nominal efficiency may also be indicated as a percentage.
- Frame size: This describes the dimensions of the motor. The motor frame size is often indicated in the model number or ‘type’. See below for more details.
- Mounting: see below for details.
- Bearing: This will be indicated as ‘DE’ for drive end and ‘NE’ for non-drive end.
- Greasing Amount and Frequency: This is often indicated within the motor manual but may also be on the motor nameplate. You may see a number followed by the letter ‘h’, which indicates that you should grease the motor after a set amount of running hours. For example, ‘3000 h’ means you should grease the motor after it’s been running for 3000 hours. You'll also see another number followed by cm3. This indicates how many grams to inject at the ‘h’ frequency.
- Duty Cycle: This is equivalent to ‘Service Factor’ in NEMA motors . Duty cycle will be denoted as S1-S10 which denotes if the motor can be used continuously or for shorter periods. It also takes into account starting, braking, no-load, and rest de-energized periods. Applications where the motor is used intermittently can use smaller motors, as they have less heat to dissipate. If the motor is running at all times, it will need to be oversized to properly dissipate the heat without damaging the motor windings.
|Continuous Running Duty||S1||The motor works at a constant load for enough time to reach temperature equilibrium.|
|Short Time Duty||S2||The motor works at a constant load, but not long enough to reach temperature equilibrium. The rest periods are long enough for the motor to reach ambient temperature.|
|Intermittent Periodic Duty||S3||Sequential, identical run and rest cycles with constant load. Temperature equilibrium is never reached. Starting current has little effect on temperature rise.|
|Intermittent Periodic Duty with Starting||S4||Sequential, identical start, run and rest cycles with constant load. Temperature equilibrium is not reached but starting current affects temperature rise.|
|Intermittent Periodic Duty with Electric Braking||S5||Sequential, identical cycles of starting, running at constant load and running with no load. No rest periods.|
|Continuous operation with intermittent load||S6||Sequential, identical cycles of running with constant load and running with no load. No rest periods.|
|Continuous operation with electric braking||S7||Sequential identical cycles of starting, running at constant load and electric braking. No rest periods.|
|Continuous operation with periodic changes in load and speed||S8||Sequential, identical duty cycles run at constant loads and given speed, then run at other constant loads and speeds. No rest periods.|
|Non-Periodic Duty||S9||The load and speed vary non-periodically.|
|Duty with Discrete Constant Loads (and speeds)||S10||The motor may be operated with a specific number of discrete loads for a sufficient time to allow the machine to reach thermal equilibrium is specified.|
The frame size number indicates height from the base of the motor to the centre of the shaft. For example, if your motor frame size is ‘80’, the centre of the shaft is 80 millimeters from the base of the motor.
This measurement can often be found in the ‘type’ or catalogue number of a metric motor nameplate.
An ‘S’, ‘M’ or ‘L’ will denote the motors length. Whether the motor is long or short, the frame size, shaft diameter, shaft length, and foot mounting holes will stay the same.
For example, take this Lafert LME71L4-230-C. The frame size on this motor is ‘71L’. The center of its shaft is 71 millimeters from the base of the motor.
Download the full IEC motor frame chart here.
Metric motors are commonly flange or face mounted, vs NEMA motors are more commonly foot mounted-pully driven and close-coupled mounted.
We see B5 and B14 used most often. An IEC B5 is equivalent to a NEMA D flange. An IEC B14 is equivalent to a NEMA C face.
Below are the most common shaft arrangements for IEC motors:
- Horizontal shaft arrangements:
- B3: foot mounted
- B5: ‘D’ type flange at drive end, no feet
- B6: foot wall mounted with feet on left hand side when viewed from the drive end
- B7: foot wall mounted with feet on right hand side when viewed from the drive end
- B8: ceiling mounted with feet above motor
- B14: ‘C’ type face at drive end, no feet
- B17: two ‘C’ or ‘D’ type flanges, foot mounted
- Vertical shaft arrangements:
- V1: ‘D’ type flange at drive end, shaft down, no feet
- V3: ‘D’ type flange at drive end, shaft up, no feet
- V5: vertical foot, wall mounted, shaft down
- V6: vertical foot, wall mounted, shaft up
- V18: ‘C’ type face at drive end, shaft down, no feet
- V19: ‘C’ type face at drive end, shaft up, no feet
- V22: skirt mounting, shaft down, no feet
Source: Baldor Motors (Baldor.com)
ATEX (Appareils destinés à être utilisés en Atmosphère Explosive) certifications refer to devices intended for us in explosion atmospheres. You may see ‘Ex’ indicated on a metric motor nameplate. This is comparable to NEMA hazardous locations ratings.
ATEX ratings are used internationally, however, they are not commonly used in North America. Keep in mind, some motors made for use in European equipment may come with an ATEX rating instead of a NEMA hazardous location rating.
Another feature to keep in mind with IEC motors is the connection box. Typically, NEMA motors will have an F-1 connection box by default, meaning, the conduit box is on the left-hand side of the frame when facing the front of the motor. Whereas the IEC motors typically come in an F-3/F-0 or F-2 mounting. An F-3/F-0 mounting has a connection box at the top of the motor.
This will factor in if replacing a NEMA motor with an IEC, or vice versa. Ensure the connection box arrangement will fit within your application.
F-3/F-0 Connection Box Orientation:
F-1 Connection Box Orientation:
It depends. Because IEC motors are less common in North America, it isn’t unheard of to cross reference an IEC motor to a NEMA model. This would typically be done if the IEC motor is out of stock or has a long delivery time.
When cross referencing an IEC to a NEMA model, the shaft sizes will be different. If the motor is pully driven, the swap is much easier. If the motor is mounted with a flange, you cannot cross reference between a NEMA motor and IEC motor because the flanges are not the same size.
Where to Buy IEC Motors in Canada
Several manufacturers have ample stock in Canadian warehouses.
WEG offers both a cast-aluminum and cast-iron option. The cast iron motors are more robust and will be able to withstand harsher applications.
Other trusted brands include Lafert, Brook Crompton, Baldor, Leeson, Marathon, Max Motion, and Nidec.
Visit eMotorsDirect.ca/motors/iec-metric-motor for a full inventory of metric motors. Our inventory is stocked across the country and most models will be delivered within 1-5 business days.