Electric Motor Nameplate: How to Read Technical Data?

Many customers often ask me how to correctly read the data on asynchronous electric motor nameplates. Therefore, I have decided to summarize some key indications regarding the motor data contained in the various boxes of the plate.

First of all, the following image shows a CE single-phase motor plate.

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Please note that the three-phase version only differs by the number in the bottom left, showing “3-M” instead of “1-M”.

Understanding the Meaning of the Numbered Boxes

Let’s look together at the meaning of the data in each numbered section:

1. Motor Type: (T: three-phase, AT: brake motor, DP: dual polarity, ME: single-phase with electronic capacitor). Frame Size: (ranging from 56 to 355). Number of Poles: (2-4-6-8-4/6-4/8…). For example, DP112B4/6 indicates a dual polarity motor, frame size 112B, with 4 and 6 poles.

2. Serial Number: Assigned by the manufacturer.

3. Protection Grade: IP 55 is the industrial standard.

4. Insulation Class: Cl.F (max temp 155°C) or Cl.H (max temp 180°C).

5. Duty Cycle: S1 (continuous), S2 (limited duration), S3 (periodic intermittent).

6. Power Factor: (cos φ).

7. Brake Data (if present): DC (direct current brake) or AC (alternating current brake).

8. Supply Voltage: Variable voltages depending on the country of use.

9. Frequency: Usually 50 or 60Hz.

10. Motor Power: Expressed in hp.

11. Motor Power: Expressed in kW.

12. RPM: Revolutions per minute.

13. Nominal Current: Current absorption in Amps.

14. Capacitor Data: (for 14 and 15, specifically for single-phase motors).

In addition, you may find other specific motor data such as:

• C3: C3 bearings.

• T: Tropicalized motor.

• 1S: Motor with 1 anti-condensation heater.

• VL: Motor with flywheel.

• A: Motor with anti-condensation holes.

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Nameplates of Certified Motors

Furthermore, nameplates of certified motors also follow the scheme proposed above. However, the certification is officially attested by a special stamp in the top left of the plate.

Below are some examples:

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Motor with UL CSA Certification

On the one hand, motors for the North American market must show the UL and CSA logos. These certifications ensure compliance with safety standards in the USA and Canada.

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ATEX Certification of the Electric Motor

On the other hand, for environments with a risk of explosion, the ATEX certification is required. In conclusion, knowing how to interpret these data is essential to avoid connection errors and ensure the safe operation of your equipment.