Dc motor is analyzed. studying common fault analysis and active maintenance technology solutions

Dc motor is analyzed. studying common fault analysis and active maintenance technology solutions - 2019 11 - 21 Beijing letter or sharp wind new energy co. , LTD. , lee chin-long ( Technology department minister) In large wind power generators, dc variable propeller system in system failure, can use dc for electricity emergency feathering, provides the high reliability of emergency stop protection, get the favour of a lot variable propeller system manufacturers. In the early days of 1. 5 mw wind turbine, LUST is analyzed. studying ( 穆格公司) , SSB change OARS, can build the oar is analyzed. studying adopts dc motor. Along with the increasing length of run, a lot of wind farms is analyzed. studying dc system frequent malfunction problems, bring many inconvenience to operation maintenance, increase the operational cost. Combined with our company under the variable propeller system maintenance case experience actively, introduce is analyzed. studying dc motor maintenance notice: 1, the principle of dc variable propeller system introduced the structure of the dc motor should be composed of stator and rotor of two parts. Direct current (dc) during stationary part called the stator, the stator's main function is to produce magnetic fields, composed of frame, main pole, commutating pole, end cover, bearing and electric brush device, etc. Runtime called rotor rotating part, its main function is to produce electromagnetic torque and induction electromotive force, is the hub of dc motor for energy conversion, so often referred to as the armature, the shaft, the armature iron core, the armature winding, commutator and fan, etc. Figure 1 - Chart 1: dc motor working principle of dc motor is the commutator with brush commutation function, make the dc electromotive force, introduced from the brush, the armature coil produces alternating electromotive force, resulting in a rotating electromagnetic torque. Common technical problems (2, dc motor 1) Sparking commutator normally between brush and commutator is' slide 'structure, the commutation generates a slight electric spark, will not cause harm to the equipment. If the commutator surface severe wear and form serious carbon brush wear, brush abnormal pressure, brush position is not in the physical the abnormal state such as bank of China online, will cause severe edm, causing further damage to the commutator, severe cases commutator insulation breakdown caused by damage, caused the entire motor damage. Figure 2 - 1: commutator discharge diagram ( 2) Breakdown armature winding and armature winding excitation winding winding short circuit breakdown occurs, winding burned down. By motor teardown found that the winding burned, generally due to motor overload high temperature for a long time, cause the winding insulation damage. Motor overload causes include electromagnetic brake can't normal open, variable propeller system mechanical stuck fault. Figure 2 - 2: the excitation winding insulation breakdown diagram ( 3) Reported for other fault is analyzed. studying the system the speed comparison, overrun faults, generally for motor speed or speed encoder damage, speed motor and speed encoder is high precision electronic devices and need to pay attention to in the operation of the harting plugs, sealing ring and encoder to tighten and inspection, to ensure reliable contact. At the same time to change speed motor carbon brush on a regular basis. Figure 2 - 3:3 variable propeller speed motor, dc motor, active maintenance content according to the characteristics of dc motor, on the active maintenance is particularly important. The following share (the main points of the dc motor active maintenance technology 1) Screw is analyzed. studying motor shell and the main place marking line, easy to maintenance after the completion of the installation. To tighten the encoder haring head. Figure 3 - 1: haring tighten checks (head and encoder 2) Of variable propeller motor armature and field winding insulation test, ensure insulation than 50 m & Omega; Above, the use of dc resistance tester measuring winding dc resistance, and record. Using the multimeter measure PT100 temperature resistance tolerance ( 20 ℃ under the resistance of 108 & Omega; Or so) 。 Testing PTC thermistor resistance in 180 & Omega; - 200Ω (between Different types of thermistor may be little different, according to the actual value judgment) 。 （ 3) Commutator for cleaning maintenance, maintenance tools in use as far as possible big cloth, cotton swabs, small brush, good to wear masks in the process of cleaning, prevent the powder into the respiratory tract, it is important to note that when carbon powder and clearing commutator small groove, the bearing inner cleaning, need to use the anhydrous ethanol in the process of cleaning. When the carbon brush for maintenance need to measure the carbon brush wear degree, if there is a severe worn, existence of mark of burning need to be replaced immediately. Figure 3 - 2: commutator maintenance cleaning ( 4) Taking pictures in the process of maintenance, in the inside of the appropriate location marking ( Such as flight number + blade) In the next maintenance well. After the maintenance, in accordance with the original disassembly steps backward installed motor, using a multimeter measuring circuit with variable propeller to coincide with the electric principle drawing, can undertake to electricity, according to the requirements of electricity is analyzed. studying do manual test, observation is analyzed. studying the direction and speed is normal.