What are the common electrical faults and solutions for series excitation motor motor stator winding machine?
1、Short circuit fault
Fault phenomenon
Motor overheating: Due to the short circuit will make the current increase abnormally, according to Joule's law (Q = I²Rt), excessive heat is generated, resulting in a sharp rise in motor temperature.
Blown fuse: Excessive current may cause the fuse to blow, causing the unit to stop working.
Burnt Winding Odor: The high temperatures generated by a short circuit may cause the winding insulation to burn, emitting a pungent odor.
Solution
Insulation resistance test: Use an insulation resistance meter to check the insulation resistance of the windings. If the insulation resistance value is too low, it indicates a possible short circuit. For minor short circuits, try drying the motor to remove moisture and restore insulation. For example, place the motor in a drying oven at 100 - 120°C for several hours.
Winding Inspection and Repair: If the fault persists after drying, it is necessary to check whether there is a turn-to-turn short circuit in the winding. This can be initially determined by observing whether there are burn marks on the appearance of the winding. For the identified short-circuit point, if at the end of the winding, you can carefully peel off the insulation to repair the short-circuit part; if inside the winding, you may need to replace the entire stator winding. Replacement to ensure that the number of turns of the new winding, wire diameter and material and the original winding of the same, and in accordance with the correct winding process.
2、Disconnection fault
Fault phenomenon
The motor can not start: because the circuit is disconnected, there is no current through the winding, can not establish a magnetic field to drive the motor, so the motor can not run.
Sudden stop during operation: If the winding is disconnected during the operation of the motor, it will suddenly stop running and there is no response when it is started again.
Solution
Multimeter test: Use the ohm gear of the multimeter to check whether the winding is disconnected. Connect the pens of the multimeter to the two ends of the winding, if the reading is infinity, it means that 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.
Replacement of the winding: If the break is inside the winding, it is usually necessary to replace the entire stator winding. After replacement, the correct connection of the winding should be checked and insulation test to ensure that the motor can work properly.
3、Overload protection failure
Fault phenomenon
Frequent tripping: During the operation of the motor, the overload protection device (such as thermal relay) operates frequently, resulting in frequent stopping of the motor.
Unable to start: Even if the motor load is normal, the overload protection device may operate incorrectly, making the motor unable to start.
Solution
Check the load: Determine if the actual load on the motor exceeds the rated load. 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.
Check the protection device: check whether the parameter settings of the overload protection device are correct, such as whether the parameters of 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、Grounding fault
Fault phenomenon
Leakage phenomenon: the motor shell is electrified, the operator will feel electrocuted when touching, which is a very dangerous situation.
Grounding protection device action: If the installation of grounding protection device (such as leakage circuit breaker), there will be frequent action of the device.
Solution
Insulation check: Use an insulation resistance meter to check the insulation resistance between the motor windings and the shell. If the insulation resistance value is too low, it means there is a grounding fault. Check that the insulation of the motor's lead wires is not damaged and that the windings inside the motor are not in contact with the housing.
Repair insulation: For the parts with damaged insulation, re-insulate them. For example, replace the insulation sleeve of the lead wires, isolate and repair the insulation of the part of the winding in contact with the shell. If the ground fault is caused by water or moisture inside the motor, the motor should be dried to remove moisture and then check whether the insulation resistance is back to normal.
5, poor electrical connection failure
Fault phenomenon
Unstable motor operation: poor connection will lead to increased resistance, so that the motor supply voltage and current is unstable, thus leading to motor speed fluctuations, torque instability.
Contact point heating: Due to the increase of contact resistance, according to P = I²R, excessive heat will be generated at the contact point, resulting in sparks or burnt contact point.
Solution
Check the connection points: Check the connection points between the stator winding of the motor 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, use sandpaper to remove the oxidized layer, then reconnect them to ensure good contact.
Replacement of connecting parts: If the crimp connection is poor, consider re-crimping or replacing the connecting terminals. After reconnection, 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.
6, controller failure (if any)
Failure phenomenon
Motor speed out of control: the controller output speed control signal is abnormal, resulting in motor speed does not meet the set value, may be too high or too low.
Motor steering error: the controller's steering control signal problem, so that the motor's steering is opposite to the expected.
Solution
Signal check: 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 motor's operating requirements. 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.
Component inspection and replacement: If the parameter settings are correct, 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, all the tests should be carried out 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.
