Open circuit of the winding machine is one of the common faults of the winding machine. If the winding machine breaks, it needs to be stopped immediately and then inspected and repaired.

Firstly, let's take a look at what causes a broken circuit in the winding machine and its impact. When a wire breakage fault occurs in the winding machine, it is called a wire breakage in the winding machine, which is a situation of internal phase loss in the motor. When there is a circuit break in the winding machine, the motor will experience a series of faults, ranging from difficulty in starting, unbalanced three-phase current, abnormal vibration, to temperature rise exceeding the controllable range, smoking, and burning of the winding machine.

（1） Cause of occurrence

The main reasons for the circuit breaker of the winding machine include that the circuit was torn during maintenance; Manufacturing process issues; Poor welding of wire ends in various components of the winding machine, overheating and desoldering; The winding machine is damaged by external force; Short circuit and grounding of the winding machine, resulting in burning, etc.

（2） Detection method

1. Observation method. The most common location for breakpoints is usually at the end of the winding machine, and it can be visually checked to see if there is any desoldering at both ends of the winding machine.

2. Multimeter or shake meter detection method. Measure the front and rear ends of each winding machine separately, and the infinite phase is the open circuit phase.

3. Power on detection method. When the motor is running normally, clamp ammeters are used to measure the three-phase current. If the three-phase current is unbalanced and the short circuit fault can be eliminated, the winding machine with the minimum current has an open circuit fault.

（3） Handling repair methods

When the circuit breaker is at the end, it should be reconnected and re soldered, wrapped with appropriate insulation and soaked in insulation paint to dry, and then covered with insulation sleeve for use.

2. The internal winding machine has a broken circuit, which cannot be repaired and the winding machine coil must be replaced.

Misconnection of the winding machine is one of the common faults of the winding machine. Misconnection of the winding machine can form an asymmetric magnetic field, which can cause difficulty in starting the motor, unbalanced three-phase current, and even burn out the winding machine.

Several situations of incorrect connection: coil insertion reversed, winding machine connection reversed; △, Y connection errors, etc.

（1） Cause of occurrence

Misconnecting △ to Y or Y to △; Reverse connection of a certain phase; Internal wiring error of the winding machine; Misjudgment of terminal output, etc.

（2） Detection method

1. Ball rolling method. It can be confirmed whether the winding machine is connected correctly based on whether the small steel balls can roll along the inner surface of the stator.

2. Multimeter detection method. Use a multimeter to check according to the wiring diagram. If there is no reading from the multimeter once, it indicates that the wire winding machine has a reverse connection.

（3） Handling method

1. It can be determined whether individual coils or coil groups are inverted based on whether the no-load current is imbalanced over a large range. At this time, the coils must be replaced, immersed in insulation paint, and finally dried.

If the judgment of the leading end is incorrect, it should be correctly judged before connecting.

3. Based on the characteristics of the surge in reverse phase current, the wrong phase of the winding machine can be identified for processing.

If Y is connected as △, the no-load current will be very high, and it needs to be corrected in a timely manner.