Motor Nameplate: Understanding the information on your electric motor

Do you have questions about the information on your electric motor's nameplate? We'll explain everything.

We've all stood in front of an electric motor's motor nameplate without understanding all the information on it. We wanted to explain all the information to you. Let's start from the beginning:

What is an asynchronous motor?

A three-phase asynchronous motor is equipment that converts electrical energy into mechanical energy. The operation is simple: this energy allows it to rotate.

Approximately 8 billion asynchronous motors are installed in the European Union, consuming about 50% of Europe's energy.

Identify the correct information on your motor nameplate.

All electric motors have a nameplate that provides the user with all necessary information. We find a lot of information such as the brand, efficiency class, serial number, type, voltage, rated current, bearing type, wiring diagram, power, speed, service, standard, country of manufacture, power factor, and IP rating. Let's review each item in detail.

1. Efficiency:

Efficiency is essential information for determining the energy consumption of your asynchronous motor. We also refer to it as efficiency class. Several efficiency classes exist, such as IE1, IE2, IE3, IE4, and IE5.

The higher the efficiency, the lower the absorbed power. Knowing that 97% of the costs generated by your electric motors are related to energy, it is wise to replace your old motors with energy-saving motors with a minimum IE2 efficiency. This way, you save energy costs sustainably. You will find our article on why to prefer an IE3 motor here.

2. Rated Power:

The rated power "Pn" of your asynchronous motor can be expressed in horsepower "HP" or in kilowatts "kW". We mainly find the power in kW on the motor nameplate. Rated power is the mechanical power exerted on the shaft. However, this is not the power consumed by your motor.

Active power "P1" is the power the motor obtains by taking into account losses generated by the electrical grid and friction. It is greater than the power exerted on the shaft.

The power indicated on your asynchronous motor will always be rated power in accordance with standard IEC 60 034–2–1:2014.

This information will be necessary to determine its size and torque depending on the speed or number of poles.

3. Serial Number:

The serial number is a sequence of numbers and sometimes letters, necessary for knowing the year of manufacture, technical information, and options. It will be requested if the customer wishes to reorder the same three-phase asynchronous motor.

4. Type of your asynchronous motor:

The type of your three-phase asynchronous motor is represented by letters and numbers. It is extremely important for finding the useful information for preparing a commercial offer. In this type, we find the efficiency, size, shaft height, and number of poles. This information will be used by your supplier.

It will be necessary to know the type of motor. There are synchronous motors, DC motors, and asynchronous motors.

5. Voltage:

Voltage is extremely important information in the choice of your electric motors. There are two types of voltage: single-phase voltage and three-phase voltage. Single-phase voltage is used for domestic applications, it will be preferable to order a 220V electric motor.

Three-phase voltage is used for industrial applications. It will always be indicated with a frequency of 50 Hz. It will be different if the motor is installed in a country that powers its installations at 60Hz.

In France, the rated voltage will always be indicated at 50Hz. The values indicated will vary depending on your network voltage, it can be:

• 230/400V or 400/690V at 50Hz
• 275/480V or 480V at 60Hz.

This information will be important depending on the starting type of your asynchronous motor.

It is also important to note that there are two types of voltage: AC voltage and DC voltage.

6. Rated Current:

The rated current is calculated based on your power and voltage (at a frequency of 50Hz). In normal operation, the rated current should not exceed the values indicated on your motor nameplate.

This current is expressed in amperes "A". It can be measured at no-load and under load to detect any potential faults in your application.

Caution: overcurrent can cause many faults in your electric motors, such as destruction of the winding and the magnetic circuit. The rated current indicated on the nameplate will be necessary for setting your motor circuit breaker and your frequency inverter.

7. Frequency:

There may sometimes be different frequencies indicated on your motor's nameplate. In France, the nominal frequency is 50Hz. However, the 60Hz frequency is regularly indicated on nameplates, which is completely normal because motor manufacturers do not only produce electric motors for the French market. The voltage 60Hz will be used mainly for other countries and continents such as Africa, Russia... Keep in mind to take all information at 50Hz.

This frequency can be modified using a frequency inverter, this type of equipment will be necessary to vary the speed of your application.

8. Speed:

The speed will always be indicated on the nameplate; it can be single or multiple depending on your application. Three-phase asynchronous motors and single-phase asynchronous motors often have a single speed. This speed will be determined based on the number of poles of your equipment.

• 2 Poles = 3000 RPM
• 4 Poles = 1500 RPM
• 6 Poles = 1000 RPM
• 8 Poles = 750 RPM
• 10 Poles = 500 RPM

However, there are electric motors with dual polarity or sometimes even triple polarity. This type of motor is often installed on old applications and will often need to be rewound.

Nevertheless, it will be possible to vary the speed of a 380V electric motor using a frequency inverter.

Bearing type:

The bearing type is interesting information on the nameplate. Not all industrial electric motors have the same types of bearings. The size, application, and power supply type will allow us to select the appropriate bearings for your asynchronous electric motor. They can be ball, roller, or angular contact bearings. It will sometimes be necessary to install bearings insulated from the harmonics of your frequency inverters. This option is recommended from size 280.

In Gamak brand electric motors, deep groove single-row ball bearings are directly included as standard.

This information is not always indicated on electric motor nameplates.

9. Wiring diagram (Motor coupling):

The wiring diagram will not always be indicated on your motor's nameplate; it may sometimes be found inside the terminal box cover. This diagram will show the different star or delta connections. This type of connection will be different depending on the supply voltage of your application.

Please note that the coupling depends on your power supply (230 V or 400 V three-phase); dual polarity motors and motors that start in star/delta will not have coupling bars.

- If your network voltage is 230/400 V and the nameplate indicates a nominal voltage of 230/400, then the star connection is highly recommended. This star connection, called star coupling, is preferred when the indicated motor voltage is similar to your network's supply voltage.

- If your network voltage is 230/400 V and the nameplate indicates a nominal voltage of 400/690 V, then the delta coupling is preferable. This delta connection is preferred when the higher supply voltage of your network (in our example, 400 V) is equal to the lower nominal voltage of your electric motor (in our example, 400 V).

10. Construction type:

There are different construction types for an asynchronous motor. The mounting will be different if your motor will be installed on a gearbox, pump, fan, or compressor.

We explain everything to you:

- The foot-mounted construction B3 "IM 1001" is very common; the B3 mounting is mainly used for applications with direct coupling, chain, or belt drive.

- The flange-mounted with through holes B5 "IM 3001" will be preferred for mounting on pumps, gearboxes, or fans. The flange sizes are often standardized.

- The flange-mounted with tapped holes B14 "IM 3601". We regularly find this type of mounting on gearboxes, pumps, and fans. It is used to reduce the overall size of your installation.

- The foot- and flange-mounted with through holes B35 "IM 2002", it combines B3 and B5 mounting.

- The foot- and flange-mounted with tapped holes B34 "IM 2101", it combines B3 and B14 mounting.

We advise you to measure the outer diameter of the flange; this is essential information when requesting a price.

11. Service:

Three-phase asynchronous motors have different operating services; the most common services are S1 and S3, but you can find other services for specific applications. You will find the list of all services.

- S1: Continuous service.

S1 service is continuous operation. Indeed, the load is constant for an indefinite duration and is equal to the motor's rated power.

- S2: Temporary service

S2 service is operation at constant load for a defined period, less than that required to reach thermal equilibrium, followed by a rest period to cool to ambient temperature.

- S3: Intermittent periodic service

S3 service is intermittent periodic service. It is a series of identical service cycles comprising a period of operation at constant load and a period of rest. The starting current does not affect heating or temperature rise.

- S4: Intermittent periodic service with starting

S4 service is intermittent periodic service with starting. Like S3 service, S4 service has a period of operation at constant load and a period of rest. It also has a starting period.

- S5: Intermittent periodic service with electric braking

S5 service is intermittent periodic service with electric braking. It is characterized by a series of service cycles comprising: a starting period, a period of operation at constant load, a period of rapid electric braking, and a period of rest.

- S6: Uninterrupted periodic service with intermittent load

S6 service is uninterrupted periodic service with intermittent load. It is a series of identical service cycles. These cycles each include a period of operation at constant load and a period of no-load operation. For this type of service, there will be no rest period.

- S7: Uninterrupted periodic service with electric starts and brakes.

S7 service is uninterrupted periodic service with electric braking. It is a series of service cycles with a starting period, a period of operation at constant load, and a period of electric braking. There will be no rest period for this type of service.

- S8: Uninterrupted periodic service with speed change

S8 service is uninterrupted periodic service with speed change. It is a series of service cycles that include a period of operation at constant load at a predetermined rotational speed, then operating under one or more other loads at different rotational speeds. There will be no rest period for this type of service.

- S9: Non-periodic speed change service

S9 service is non-periodic speed change service. In this type of service, the load and speed generally have non-periodic variation within the operating range.

12. Brand or manufacturer:

Many electric motor brands exist on the French and international markets. It is important to know the manufacturing origin and the reputation of the brand or manufacturer of your asynchronous motor to guarantee the reliability of your equipment. The most well-known brands are Gamak, Leroy-Somer, Siemens, Abb, Nidec, Vem, Almo, Cemer, SEW, and Weg.

13. European standard:

Your electric motor's nameplate indicates which standards regulate it. Depending on the country, standards may differ and will have a different name.

For example, there is:

• The CE mark - European Conformity: the manufacturer commits and is responsible for ensuring the conformity of its product according to the requirements of European Union laws.
• The IEC standard, or CEI in French, of European origin - International Electrotechnical Commission: it is an international standardization organization whose purpose is to deal with the fields of electronics, electricity, and related technologies.

You can find these standards on our diagram at No. 14: CE standard and IEC 60034, which corresponds to the standard concerning the rotation of electrical machines.

14. Country of manufacture:

On this nameplate, you can find the country where your electric motor was manufactured. For Gamak brand electric motors, they are all entirely designed in Turkey in a single factory.

15. Power factor (Cos Phi):

Cos Phi, meaning Cosine Phi, is a necessary characteristic for calculating your motor's electrical consumption.

16. IP rating:

This characteristic corresponds to the level of protection your electric motor provides against liquid or solid bodies and the risks present in your professional environments.

It is followed by 2 digits: IPXX :

• The first corresponds to protection against liquid bodies. It can range from digit 0 to digit 6.
• The second corresponds to protection against solid bodies. As for it, it can range from digit 0 to digit 9.

Thus, it should not be understood as an index followed by a number but by 2 distinct digits.

For example, the IP55 protection rating at No. 16 of our nameplate corresponds to protection against dust and water jets.

17. 3~MOT:

3~MOT means that your electric motor is a three-phase AC motor. In other cases, your motor may be single-phase for domestic applications.

 

We hope this article helps you understand all the information on your asynchronous motor's nameplate.