Transducer injures the secret that electric machinery must know

Time:2023-06-14 12:05:28
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source:MOMEYER CNC Machining

Introduction: Transducer includes two fields to the injury of electric machinery, the injury of the injury of stator winding and bearing, if pursue,1 is shown. This kind of loss occurs in a few weeks to come commonly inside ten months, a lot of element such as temperature of the cable length between the carrier wave frequency of the power of the brand of specific time and transducer, brand of electric machinery, electric machinery, transducer, transducer and electric machinery, environment is concerned. The secret transducer that transducer injury electric machinery must know is right the injury of electric machinery: Transducer includes two fields to the injury of electric machinery, the injury of the injury of stator winding and bearing, if pursue,1 is shown. This kind of loss occurs in a few weeks to come commonly inside ten months, a lot of element such as temperature of the cable length between the carrier wave frequency of the power of the brand of specific time and transducer, brand of electric machinery, electric machinery, transducer, transducer and electric machinery, environment is concerned. The inchoate accident of electric machinery damages the production of the enterprise brings huge pecuniary loss. This kind of loss is electric machinery not only maintain and change brought charge, mainer is the pecuniary loss that accident stop production brings. Accordingly, when electric machinery of use transducer drive, the problem that must injure to electric machinery has enough attention. The transducer injury to electric machinery the distinction of transducer drive and labour frequency drive: The mechanism that should understand labour frequency electric machinery to damage more easily below transducer drive condition, the voltage that understands transducer drive electric machinery above all and labour frequency voltage have what distinction. How don't understanding this differentia again next produce undesirable effect to electric machinery. The basic construction of transducer is shown 2 times like the graph, include rectification circuit and inversion circuit two parts. The volts d.c. that rectification circuit forms for common diode and filter wave capacitance outputs circuit, the voltage that inversion circuit becomes volts d.c. commutation wide modulation of arteries and veins is undee (PWM voltage) . Accordingly, the voltage weaveform of transducer drive electric machinery is the pulse weaveform of broad change of arteries and veins, is not weaveform of sine wave voltage. Cause the prime cause that electric machinery damages easily namely with electric machinery of pulse voltage drive. Transducer injures the mechanism of winding of electric machinery stator: Pulse voltage is transmitted on cable when, if the impedance of cable and laden impedance do not match, in load end can produce reflection. Catoptric result is, incident wave and reflection wave overlay, form taller voltage, its extent can achieve 2 times of dc generatrix voltage greatly most, be equivalent to transducer inputting 3 times of voltage about, if pursue,3 are shown. Exorbitant aiguille voltage is added on the coil of electric machinery stator, cause voltage impact to coil, frequent overvoltage concussion can cause electric machinery premature invalidation. The electric machinery of transducer drive gets after the concussion of aiguille voltage, its real life and very much element, include, the element such as the craft of frequency of temperature, pollution, oscillatory, voltage, carrier wave and coil insulation is concerned. The carrier wave frequency of transducer is taller, weaveform of output electric current is close to sine wave more, this meeting drops the moving temperature of electric machinery, prolong the life of insulation thereby. But, taller carrier wave frequency means the more of aiguille voltage amount that per sec. produces, more to the percussive frequency of electric machinery. Graph 4 gave out the insulation life change as cable length and carrier wave frequency. From inside the graph knowable, to 200 feet long cable, raise 12kHz from 3kHz when carrier wave frequency (change 4 times) when, the life of insulation is reduced from about 80 thousand hours (differ 4 times) . Carrier wave frequency is taller to the affects electric machinery temperature of insulation, the life of insulation is briefer, if the graph is shown 5 times, lift when temperature 75 degrees when, the life of electric machinery has 50 ％ only. The electric machinery of transducer drive, because PWM voltage includes more high frequency component, electric machinery temperature is met the circumstance of drive of voltage of outclass labour frequency. Transducer injures the mechanism of electric machinery bearing: The reason that transducer injures electric machinery bearing is, have the electricity that has shed bearing, and this is planted electric current is in intermittent connecting condition, intermittent connecting circuit can produce electric arc, electric arc burn down bearing. The matter that the bearing midstream that causes alternating current engine lives electric current basically has two, the first, in-house electromagnetism field is lopsided the inductive voltage of generation, the 2nd, the access of high frequency electric current that stray capacitance causes. The magnetic field of interior of electric machinery of ideal communication induction is symmetrical, the electric current when three-phase winding is equal, and phasic differ 120? When, voltage won't go out in the induction on the axial lever of electric machinery. When the PWM voltage that transducer outputs brings about the magnetic field asymmetry of electric machinery interior, can give voltage in the induction on axial lever, the extent of voltage is in 10 ～ 30V, this and driving voltage are concerned, driving voltage is taller, the voltage on axial lever is taller. When the insulation intensity of the lube in exceeding bearing when the numerical value of this voltage, can form access of an electric current. Axial lever rotates in the process, in a certain hour, the insulation of lube block broke electric current. This process is similar to mechanical switch open a process, the meeting in this process produces electric arc, the surface of bowl of ablation axis lever, ball, axis, form indentation. If do not have exterior vibration, small indentation won't have produced big effect, but if have exterior vibration when, can produce groove, this is very big to the locomotive influence of electric machinery. Additional, the experiment makes clear, the voltage on axial lever still outputs voltage with transducer base wave frequency is concerned, base wave frequency is lower, the voltage on axial lever is taller, bearing injury is more serious. In the initial stage of motor job, when lube temperature is inferior, voltaic extent is in 5 - 200mA, so small electric current won't produce any damage to bearing. But, after motor moving period of time, lift as lube temperature, peak value electric current can be achieved 5 - 10A, this meeting produces flying arc, small hole is formed in the surface of bearing component. The protection of winding of electric machinery electron: When the length of cable exceeds 30 meters, contemporary transducer can carry generation aiguille voltage in electric machinery necessarily, shorten the life of electric machinery. Avoid electric machinery occurrence loss, have two train of thought, one is to use winding insulation to fight the electric machinery with electric higher intensity (call frequency conversion electric machinery commonly) , another is to adopt measure to reduce aiguille tension. Before one kind of measure agrees with newly-built project, a kind of measure agrees with after right already some electric machinery undertake transforming. At present method of commonly used electric machinery protection has the following 4 kinds: 1) in the output of transducer end installs reactor: This measure is the most commonly used, but those who need an attention is, this method to shorter cable (30 meters the following) have certain effect, but sometimes the effect is not quite ideal, if pursue 6 (C) be shown. 2) in the output of transducer end installs filter of Dv ／ Dt: This measure applies to cable length to be less than 300 meters circumstance, the price reactor of summary prep above, but the effect had clear improvement. 3) in the output of transducer end installs sine wave filter: This measure is optimal. Because be here, turned PWM pulse voltage into sine wave voltage, it is electric machinery the job falls in as same as labour frequency voltage condition, the problem of aiguille voltage got complete settlement (cable is again long, also won't appear aiguille voltage) . 4) in the position of cable and electric machinery interface installation aiguille voltage absorbs implement: The defect of a few measure is in front when the power when electric machinery is greater, the bulk of reactor or filter, weight is very great, the price is higher, additional, reactor and filter can cause certain voltage drop, affect the output moment of force of electric machinery, use transducer aiguille voltage to absorb implement can overcome these weakness. The reason that electromotor damage still has laden side (1) overload of dynamoelectric pilot time moves. (2) the electromotor Yu Pin that start is numerous, the time that start grows too or start time interval too short. (3) be procrastinated to use mechanical failure, make electromotor exerts oneself increase, or be lived not to turn by card or rotate speed drops quickly, make electromotor electric current jumps and overheat. (4) the duty type of electromotor and laden duty do not match, for example short when the load that the electromotor of periodic duty uses at driving successive permanent worker to make. Other returns some is not very common cause, be like: Too low or voltage is exorbitant, shake cause wiring column pine to take off alternate with short circuit, voltage of electric machinery of bug rat harm, entrance and domestic voltage do not cooperate (like Japanese electric machinery) . Starting loop breakdown causes all sorts of decompression to be not changed, job of low pressure of electric pilot time. Electromotor burns the overhaul method of caustic: Electromotor changes winding coil, undertake dry drying is handled after dip insulating varnish; Change bearing; Rebuild rotor core. Transducer injures the mechanism of electric machinery bearing to have the electricity that has shed bearing, and this is planted electric current is in intermittent connecting condition, intermittent connecting circuit can produce electric arc, electric arc burn down bearing. The matter that the bearing midstream that causes alternating current engine lives electric current basically has two, the first, in-house electromagnetism field is lopsided the inductive voltage of generation, the 2nd, the access of high frequency electric current that stray capacitance causes. The magnetic field of interior of electric machinery of ideal communication induction is symmetrical, the electric current when three-phase winding is equal, and phasic differ 120 when, voltage won't go out in the induction on the axial lever of electric machinery. When the PWM voltage that transducer outputs brings about the magnetic field asymmetry of electric machinery interior, can give voltage in the induction on axial lever, the extent of voltage is in 10 ～ 30V, this and driving voltage are concerned, driving voltage is taller, the voltage on axial lever is taller. When the insulation intensity of the lube in exceeding bearing when the numerical value of this voltage, can form access of an electric current. Axial lever rotates in the process, in a certain hour, the insulation of lube block broke electric current. This process is similar to mechanical switch open a process, the meeting in this process produces electric arc, the surface of bowl of ablation axis lever, ball, axis, form indentation. If do not have exterior vibration, small indentation won't have produced big effect, but if have exterior vibration when, can produce groove, this is very big to the locomotive influence of electric machinery. Additional, the experiment makes clear, the voltage on axial lever still outputs voltage with transducer base wave frequency is concerned, base wave frequency is lower, the voltage on axial lever is taller, bearing injury is more serious. In the initial stage of motor job, when lube temperature is inferior, voltaic extent is in 5 - 200mA, so small electric current won't produce any damage to bearing. But, after motor moving period of time, lift as lube temperature, peak value electric current can be achieved 5 - 10A, this meeting produces flying arc, small hole is formed in the surface of bearing component. CNC Milling