Talking about motor stator lead and electrical fault
The stator lead is a problem that every motor will involve. In the design process, the parameters related to product design performance, such as lead cross-section and lead insulation, are generally considered. In the manufacturing process, not only the lead cable parameters are required to meet the design requirements, but also more details need to be controlled, a little careless. This can lead to catastrophic failure of the motor. Ms. Participated in a joint exchange with the work today to talk with everyone about the control points of the motor lead wire in the motor manufacturing process.
Conductor cross section and diameter control
In the product design process, not only the lead cross-section conformity should be considered, but also the operability of the motor production and processing process should be fully considered. Especially for large-size motors, it is necessary to have a large flow guiding area, and usually there is no need to consider the problem at all. Serious mistakes will occur due to habitual thinking patterns. If the single lead section is too large, the lead wire welding is unreliable, the casing cannot be led out, the lead wire and the terminal block are not connected at all, and the like. The usual practice of this problem is mostly solved by selecting a small-area lead in parallel, but the total number of leads is increased, and there is always a small episode and a big error in the wiring link.
Ms. See a low-voltage high-power motor with 24 leads of a motor. The motor is a delta connection, and each lead has 4 leads. The motor customer is very careful when maintaining the motor. The A, B and C labels are very clear. The connection fastening link did not know how to make the wiring wrong, which caused the motor to start, and was later fixed by the service personnel of the manufacturer.
The lead wire is connected to the wire with a weak or missing wire
This is the most problematic part of a large-size product. Especially when the stator is in a lot of lines, the problem will be more serious. In order to ensure the reliability of welding, the motor manufacturer will improve the final welding effect through argon arc welding and medium frequency welding. However, due to the uncleanness of the paint on the wire welding head, the effect is greatly reduced; some motor factories use the connection tube. In the cold pressing process, the lead wire and the wire are crimped together by the connecting pipe, and the matching relationship between the pipe diameter and the wire core is not well grasped, and the reliability of the connection is still highly volatile.
Hard lead problem
The VPI dipping process greatly improves the insulation level of the motor, but the lead wire cores are also filled with lacquer, which leads to hard wires and no flexibility. Leading and wiring are difficult, core breakage, insulation cracking and other defects frequently occur. . For this reason, many motor manufacturers adopt the process of first dipping and then drawing the lead wire, but the process is relatively cumbersome, and the stator winding of the soldered lead after immersion paint has poor overall curing effect and low reliability.
Lead and terminal connection
According to the connection process of the current motor manufacturers, most of them are fixed by cold pressing, and are completed before dipping, which basically ensures the reliability of the connection. However, it should be emphasized here that the material of the joint end must meet the design requirements, otherwise the inferior joint end will cause the joint end to break during the cold pressing process and the later wiring.
Lead outlet control
If the lead wire outlet has a casting flash, a sharp edge of the junction box, etc., it will lead to electrical failure caused by damage to the wire during the lead-out process and when it is put into operation.
Lead protection and fixing
In the manufacturing process, the protection of the lead wire during the operation of the motor should be fully considered. Appropriate fixing measures should be taken according to the actual condition of the lead wire to prevent the insulation damage caused by the vibration of the lead wire and the repeated friction of the related components. Especially for high-voltage motors, the protection of the leads is more important due to the inherent characteristics of the core and the base.
Reprinted from the network