What are the common electrical faults and solutions for DC motor motor automatic oven machine?
DC motor motor automatic oven machine common electrical faults and solutions are as follows:
1, power failure
Failure phenomenon: the power indicator does not light, the motor can not start.
Possible causes: the power plug is not plugged in, power switch damage, fuse blown, power cord breakage.
Solution: Check whether the power plug is plugged in tightly, try to replace the power switch, check whether the fuse is blown and replace it, use a multimeter to check whether the power cord is broken and repair or replace 123.
2, motor failure
l can not start
Failure phenomenon: the motor does not rotate after power on.
Possible causes: the power supply is not connected, the motor lead wire short circuit or touch the shell ground, brush and commutator contact is poor, motor overload, excitation winding there is a short-circuit or disconnection fault, part of the main magnetic pole polarity is reversed, armature winding line there is a disconnection fault and so on.
Solution: Use a multimeter to check the connection and contact of power supply lines and electrical switches, etc., so that they are connected and in good contact; check and deal with the short circuit between the lead wires and grounding faults on the chassis; check the contact between the brushes and commutator, and observe whether the brushes are stuck inside the brush grip and can't slide freely, or whether the contact surface is too small, etc., and deal with them accordingly if there are any problems; lighten the load of the motor; check the excitation winding, and find out whether there is a short circuit or a broken circuit. Check the excitation winding, find out the short circuit or broken point for repair; check the polarity of the main pole coil of the excitation winding, find out the wiring error and correct it; use a multimeter or resistance meter to measure the resistance of the armature winding circuit, as well as the resistance of the commutation winding and the compensation winding, find out the fault point and repair it.
l Running speed is too low or uneven
Fault phenomenon: the motor speed does not reach the rated speed, or the speed fluctuates greatly during operation.
Possible causes: short-circuit fault in armature winding, short-circuit fault between commutator pieces of armature, incorrect position of brushes, wrong polarity of stator commutator winding, low voltage of power supply etc.
Solution: Check and measure to find out the short-circuit point of armature winding, repair or replace the armature winding; check the whole commutator piece between the situation, carefully clean up the commutator piece between the solder, copper, burrs and other residues, eliminate potential short-circuit failure point; adjust the brush position; check and confirm the commutator winding polarity is connected wrongly to rectify the wiring; adjust the power supply voltage, so that it reaches the rated value.
The speed is too high and accompanied by violent sparks2 :
Fault phenomenon: motor speed is obviously higher than the rated speed, and the commutator produces violent sparks.
Possible causes: excessive resistance of excitation winding or broken circuit, short circuit between turns of excitation winding, wrong polarity of parallel excitation winding, short circuit or broken circuit faults in armature winding, series excitation motor load is too light, wrong polarity of series excitation winding of re-excitation motor, brush deviation from the original normal position, and so on.
Solution: use the resistance of the multimeter to carefully detect all the wiring terminals in the excitation winding circuit with or without poor contact due to oxidation, so that the resistance of the excitation circuit is restored and reaches the normal resistance value; check and measure to confirm the scope of the short-circuit fault, and repair or replace the excitation winding depending on the specific circumstances; find out and confirm that the excitation winding polarity wiring errors and rewire the winding in accordance with the correct method; check and measure the point of the short-circuit or disconnection, and repair or replace the armature winding depending on the specific circumstances. Repair or replace the armature winding according to the specific situation; after checking the series excitation motor is indeed too light load, increase the load appropriately to facilitate the start; carefully check the wiring of the series excitation winding, find out the error and rewire it according to the correct method; after checking the position of the brushes is indeed a shift in the fault, the brushes can be reconfigured according to the original marking, or use the inductive method to find out the correct position of the brushes, and reconfigure the brushes.
l Armature overheating during operation
Fault phenomenon: The armature temperature is too high after the motor has been running for a period of time.
Possible reasons: motor overload or over the provisions of frequent starting, armature winding short circuit or grounding fault, short circuit between the commutator piece, brush spring pressure is too large commutator abnormal heat, armature and stator pole friction, stator main pole air gap is not uniform, motor cooling conditions deteriorate, parallel excitation or re-excitation of the motor's power supply voltage is too low, and so on.
Solution: reduce the load or reduce the frequent start; check and measure the exact position of the short circuit or grounding of the winding, repair or replace the armature winding as appropriate; clear away the solder, copper chips and burrs between the commutator pieces; adjust the brush spring pressure; check whether the motor large and small end caps and the core of the magnetic pole have loose bolts or fastening is not in place, find out the fault and repair; check the main magnetic pole of the stator and to be adjusted evenly; Clean the dust filter, air duct, check the fan for defects; use a voltmeter to measure the power supply voltage, find out why the voltage is low and restore it to the rated value.
3、Failure of frequency converter
l overcurrent fault
Failure phenomenon: The frequency converter shows overcurrent alarm, and the motor may shake or fail to run normally.
Possible reasons: the acceleration and deceleration time of the frequency converter is set too short, sudden change of load, uneven distribution of load, short circuit of output, motor and cable failure.
Solution: Extend the acceleration and deceleration time, reduce the sudden change of load, apply energy-consuming braking components, design the load distribution, check the wiring; check the insulation of the motor and cable to make sure that there is no short-circuit or ground fault.
l Overvoltage fault
Fault phenomenon: The frequency converter displays over-voltage alarm and the motor may stop running.
Possible reasons: over-voltage of input AC power supply, over-voltage of power generation.
Solution: When the input AC power supply is over-voltage, disconnect the power supply, check and deal with it; if the over-voltage of power generation is caused by the small deceleration time setting of the frequency converter when dragging the large inertia load, install the regenerative braking unit or modify the parameters of the frequency converter and set the deceleration time of the frequency converter to be longer; if it is caused by the lack of load distribution when multiple electric actuators are loaded with the same load, it is necessary to carry out the adjustment of the load distribution.
l Overload fault
Failure phenomenon: the frequency converter shows overload alarm and the motor may be overheated.
Possible causes: overload of the inverter itself and motor overload, overload of the inverter is caused by too short acceleration and deceleration time and too much DC braking capacity, motor overload may be caused by too low voltage of the power grid, overload, poor mechanical lubrication and other reasons.
Solution: Extend the braking time by changing the internal parameters of the frequency converter; check the grid voltage and load conditions, choose the right motor and frequency converter, check the mechanical lubrication and deal with it accordingly.
※ If you still can't solve the equipment failure by the above ways and means, please contact the technical specialist of Xinhui Electromechanical Equipment Co.
