Content:
- Modern designation and interpretation of parameters of electric motors
- Connection diagram and decoding of terminal designations in the box
- Imported engine marking
- Determination of motor parameters in the absence of a nameplate
- Motor marking for radio-controlled models
Modern designation and interpretation of parameters of electric motors
The marking has several basic positions:
- brand (type) of electric motors;
- execution option;
- working length of the axis of rotation;
- mounting dimensions of the mount;
- core length;
- number of pole pairs;
- modification of the structure;
- Climatic performance.
Below is a decoding of the designations of modern engines.
Below you can see an example of the complete marking of induction motors and its decoding.
The degree of protection of the electric motor against dust and moisture according to the IP class is also indicated, in numbers from 0 to 8. Here, the first number is dust protection, and the second is moisture protection.
In this case, the name indicates the mounting design. Using the mounting design code, you can determine how the motors are mounted - on feet or using a flange. For example, IM 1081 speaks of foot mounting, and that it can be installed with the shaft up, down or horizontally.
For an electric actuator in an explosion-proof design, the package of accompanying documents must contain a certificate, which indicates the marking according to the degree of explosion protection, according to its type and scope. Also, in the marking of the engine, if the letter B is indicated at the beginning, it is explosion-proof, for example BA07A (M) -450-710.
In this case, the designation of DC motors differs from AC and has the form shown in the figure.
The figure below provides information on traction motors mounted on cranes.
Similar data can be found on the nameplates of electric motors.
The information on the plate says that:
- AIR - a type of asynchronous machine;
- 80 - shaft length;
- A-mounting dimension;
- 4-number of poles;
- U- designed to work in temperate climates;
- 3-installed indoors.
The power is 1.1 kW, the rotational speed is 1420 rpm. It can operate on AC 220 or 380 volts when the windings are turned on triangle or star.
The consumption current will be 4.9 / 2.8A, respectively. Protection degree IP54. Produced in the Republic of Belarus.
Connection diagram and decoding of terminal designations in the box
The electric motor has a terminal box, it is also called "brno". Where the terminals of the beginning and end of the stator windings are attached to the bolts.
The above figure shows the terminal box, and the figure below shows designation of the terminals of the windings, by bridging which in a certain way, you can get a delta connection or star:
- U1 is the end of the first winding, and W2 is the beginning of the third;
- V1 is the end of the second, and U2 is the beginning of the first;
- W1 is the end of the third, and V2 is the beginning of the second.
By jumpering the contacts U1, V1, W1 we get a star connection of the windings, and by jumpering the pairs of contacts U1 with W2, V1 with U2, W1 with V2 - the windings are connected by a triangle.
Imported engine marking
The same markings are used on imported electric motors.
The picture shows the nameplate of an electric motor made in Italy. Where the markings are similar to domestic engines, but according to European standards. According to these data, you can pick up a domestic analogue.
The German firm Siemens produces electric motors for various purposes. In this case, the designation on the nameplate is applied to the data for the standard voltage, but for different frequencies of the supply voltage. The figure below shows the decoding of the information from the Siemens engine nameplate.
A similar marking of electric motors is placed on the nameplates of Chinese manufacturers. Often they produce products under well-known brands, such as the same Siemens.
Determination of motor parameters in the absence of a nameplate
If there is no nameplate on the engine, and there is no passport, the question arises of how to determine its power. There are several ways to do this:
- Having measured the diameter and length of the shaft, its parameters are calculated according to the table.
- Knowing the overall and mounting dimensions, you can use this information to select electric motors, according to the tables that you will find at the link below.
- Having measured the resistance of the windings, the power is determined by the formula. To do this, measure the resistance when connected with a star. Divide the result by 2. We substitute the obtained data into the formula: P = (220v * 220v) / R, multiply the resulting figure by 3, this will be the required power. When connecting with a star, the calculation is performed according to the same formula, the result is multiplied by 6. We get the required power.
- Having connected the motor to the network, the idle current is measured with an ammeter. After that, according to the data in the table, the selection of engines is made.
This situation often occurs in production. Therefore, electricians must understand how to find out the power of the engines in the absence of a nameplate.
When connecting an electrician, it is necessary to take into account the direction of rotation of the drive shaft connected to the pumps. This applies to both three-phase and single-phase motors. Some motors have an arrow on the body to indicate the direction of rotation.
We wrote about this in detail in a separate article published earlier - https://samelectrik.ru/kak-opredelit-moshhnost-elektrodvigatelya.html.
Motor marking for radio-controlled models
The marking of brushless motors on the model has two indicators: stator dimensions, diameter / height or external dimensions. They are indicated by a four-digit numerical value, for example, 2212. The first two digits define the diameter and the second the length of the stator in millimeters.
Please note that the dimensions are not indicated for the housing, but for the stator. The above motor type 2212 is an outrunner by design, that is brushless motor with an external rotor. The dimensions of its case will differ from 22 and 12 mm.
However, the external dimensions of the stator are a marketing ploy of sales managers, because there can be any winding in it.
So we examined what kind of marking of electric motors is and their decoding. If you have any questions, ask them in the comments below the article!
Related materials:
- Decoding of marking of wires and cables
- What are the brushes for electric motors and how are they marked
- Conventional designation of motors on the diagram
