What are the common electrical faults and solutions for series excitation motor motor stator press end plate machine?
1、Short circuit fault
Fault phenomenon
The motor runs with abnormal heat and may even smoke. This is because the short-circuit leads to excessive current, according to Joule's law (Q = I²Rt), the current increases so that the heat generated increases dramatically.
The motor may rotate at an erratic speed or may not start properly. Since the short-circuited portion of the motor will change the electromagnetic characteristics of the motor, it will affect the normal distribution of the stator magnetic field, which in turn will interfere with the torque output and speed control of the motor.
Solution
Use an insulation resistance meter to check the insulation resistance of the stator windings. If the insulation resistance value is too low, it indicates a possible short circuit point. For minor short circuits, try to restore the insulation by drying, e.g. place the stator in a thermostat and dry it for a few hours at a suitable temperature (e.g. 100 - 120°C) to remove moisture from the windings.
If the short circuit is more serious, e.g. a short circuit between turns within the windings, it may be necessary to replace the damaged stator windings. In the replacement of the winding, to ensure that the new winding turns, wire diameter and material and the original winding of the same, and in accordance with the correct winding process for the operation, including the winding of the winding direction, embedded wire way.
2、Break fault
Fault phenomenon
The motor can not start at all. Because the current path is disconnected, there is no current through the stator winding, can not establish a magnetic field, the motor naturally can not run.
Sometimes the motor suddenly stops during operation and there is no response when it starts again. This is due to vibration, overheating and other factors during operation that cause the connection points of the windings or the wires themselves to break, causing the motor circuit to be disconnected.
Solution
Firstly, use the ohm gear of the multimeter to check whether the stator winding is disconnected or not. Connect the pens of the multimeter to the two ends of the winding, if the reading is infinite, it means the winding is disconnected. For cases where the break is at the end of the winding, try reconnecting the break, using soldering or crimping to ensure a good connection and good insulation.
If the break is inside the winding, it is usually necessary to replace the entire stator winding. After replacement, the winding should be connected to the correctness of the inspection and insulation test to ensure that the motor can work properly.
3, overload protection device action fault
Fault phenomenon
The motor stops soon after starting, and the overload protection device (such as thermal relay) operates frequently. This may be due to the actual load of the motor exceeds its rated load, or overload protection device parameters are set incorrectly.
The overload protective device operates incorrectly even if the motor load is normal. This may be due to a fault in the protective device itself, such as aging or damage to internal components or external interference.
Solution
Check the load on the motor to determine if there are any overload factors. For example, check whether the driven mechanical parts are jammed or have excessive friction. If it is a load problem, you need to eliminate mechanical problems or adjust the load so that it is within the rated range of the motor.
For overload protection device parameter setting problems, check whether the parameter settings such as the rated current of the thermal relay match the rated current of the motor. If it does not match, readjust the parameters of the protective device according to the rated current of the motor. If you suspect that the protective device itself is faulty, you can use the replacement method, replace a new overload protection device of the same type for testing.
4, poor electrical connection fault
Fault phenomenon
Sparks or arcs appear when the motor is running, especially near the electrical connection point. This is because the poor connection leads to increased contact resistance, according to Ohm's law (U = IR), in the current through the connection will produce a higher voltage drop, thus triggering a spark or arc.
The motor runs erratically, with high and low speeds or intermittent stalls. This is due to the unstable resistance of the circuit due to poor connections, which affects the supply voltage and current to the motor, resulting in fluctuations in torque and speed.
Solution
Check the connection points between the motor stator winding and the power supply, controller and other components. Check to see if the connection bolts are loose, the terminals are oxidized or the crimping is secure. For loose bolts, re-tighten them; for oxidized terminals, sandpaper can be used to remove the oxidized layer, then reconnect them and ensure good contact.
If the crimp connection is poor, consider re-crimping or replacing the connection terminal. After reconnecting, you can use infrared thermography and other tools to check the temperature of the connection point to ensure that the connection is good and will not be overheated and fail again.
5, controller failure (if any)
Failure phenomenon
The motor does not run at the set speed and direction. This may be because the controller's output signal is abnormal, such as control voltage, frequency, etc. does not meet the requirements.
The motor shows abnormal vibration or noise, which may be due to the distortion of the current waveform output from the controller, resulting in an unstable magnetic field of the motor, generating additional vibration and noise.
Solution
Use an oscilloscope or other equipment to check the output signal of the controller. Observe whether the voltage and current waveforms are normal, and whether the frequency and amplitude meet the operating requirements of the motor. If abnormal signals are found, first check whether the parameter settings of the controller are correct, such as speed given, torque compensation and other parameters.
If the parameters are set correctly, the electronic components inside the controller (such as power transistors, integrated circuits, etc.) may be damaged. For damaged components, you can try to replace the same type of components to repair. After replacing the components, carry out all the tests to ensure that the controller can normally output signals to drive the motor operation.
※ If the above ways and means still can not solve the equipment failure, please contact Xinhui Electromechanical Equipment Co., Ltd. through the page chat tool to seek help.
