Buke servo motor - what are the main components of the motor?

The main components of the motor include: 1. a frame; 2. an iron core; 3. a winding; 4. an end cover; 5. a bearing; 6. Centrifugal switch or starting relay and PTC starter; 7. a nameplate.

1 frame

The frame structure varies depending on the motor cooling method, protection type, installation method, and purpose. According to its material classification, there are several types of cast iron, cast aluminum and steel plate structures. Cast iron frame with ribs. The base is connected to the end cap and fastened with bolts. Cast aluminum machine bases generally do not have heat dissipation ribs. The steel plate structure base is made of thin steel plate with a thickness of 1.5-2.5 mm, which is rolled and welded, and then welded to the foot of the steel plate stamping part. Some special motors have a rather special base, such as the motor of a refrigerator, which is usually packed in a sealed jar with the compressor. The motor of the washing machine, including the motor of the dryer, has no base, and the end cover is directly fixed on the stator core.

2 iron hearts

The core includes a stator core and a rotor core, which acts like a three-phase asynchronous motor and is used to form a magnetic circuit for the motor.

3 windings

The stator winding of a single-phase asynchronous motor is often made into two phases: the main winding (working winding) and the secondary winding (starting winding). The central axis of the two windings is staggered by a certain electrical angle. The aim is to improve start-up performance and operational performance. The stator windings are mostly wound with high-strength polyester enameled wire.

The rotor winding generally adopts a cage winding. It is commonly used for aluminum die-casting.

4. End caps

There are also iron castings, aluminum castings and steel plate stamping parts corresponding to different base materials and end covers.

5 bearings

Bearings include ball bearings and oil-impregnated bearings.

6. Centrifugal switch or starter relay and PTC starter

(1) Centrifugal switch

In single-phase asynchronous motors, in addition to the capacitive running motor, in the starting process, when the rotor speed reaches about 70% of the synchronous speed, the starting windings of the single-phase resistive starting asynchronous motor and the capacitor starting asynchronous motor are often cut off with the help of centrifugal switches, or the starting capacitors of the capacitor starting and running asynchronous motor are cut off. Centrifugal switches are generally installed on the inside of the shaft extension end cover.

(2) Starting relay

Some motors, such as refrigerator motors, are replaced by starter relays because they are assembled with the compressor and placed in a sealed jar that is not convenient for installing centrifugal switches. The suction coil of the relay is connected in series in the main winding circuit, and when starting, the main winding current is very large, and the armature action makes the dynamic contact connected in series in the secondary winding circuit closed. So the secondary winding is turned on, and the motor is in the two-phase winding running state. As the rotor speed increases, the main winding current decreases and the suction power of the suction coil decreases. When a certain speed is reached, the suction force of the electromagnet is less than the tension of the reaction spring of the contact, the contact is opened, and the secondary winding is disengaged from the power supply.

(3) PTC starter

The latest actuating element is the "PTC", which is a thermistor that can be "turned on" or "off". PTC thermistors are a new type of semiconductor element that can be used as delay-type starter switches. When used, the PTC element is connected in series with the secondary windings of a capacitive-started or resistive-started motor. At the beginning of starting, because the PTC thermistor has not yet been heated, the resistance value is very low, the auxiliary winding is in the path state, and the motor starts to start. With the passage of time, the speed of the motor increases, and the temperature of the PTC element rises due to its own Joule heating, and when it exceeds the Curie point Tc (that is, the temperature point where the resistance increases sharply), the resistance increases dramatically, and the secondary winding circuit is equivalent to disconnecting, but there is a small maintenance current, and there is a loss of 2-3 watts, so that the temperature of the PTC element is maintained above the Curie point Tc value. When the motor stops running, the temperature of the PTC element continues to drop, and its resistance value drops below the Tc point for about 2-3 minutes, at which point it can be restarted, which is exactly the downtime between the refrigerator and the air conditioner.

Advantages of PTC starter: no contact, reliable operation, no noise and no electric spark, good fire and explosion resistance. And vibration resistance, shock resistance, small size, light weight, low price.

7 nameplates

Including: motor name, model, standard number, manufacturer name, factory number, rated voltage, rated power, rated current, rated speed, winding connection, insulation grade, etc.

Buke servo motor - what are the main components of the motor?

Buke servo motor - what are the main components of the motor?

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