Transducer timing device uses shallow analyse

Increase the impedance inside transducer power supply source to connect general reason condition to fall, the internal resistance of power source equipment fights what can have electric capacity of wave of filter of amortize transducer dc not to have the action of result power. This kind of internal resistance fights the short circuit impedance that is transformer. When power source capacity opposite transducer capacity is jumped over small, impedance value is jumped over relatively inside big, harmonic content is smaller; Power source capacity is jumped over relative to transducer capacity big, criterion internal resistance fights a value to be jumped over relatively small, harmonic content is bigger. When choosing transformer of transducer power supply source so, had better choose the transformer of the Chinese People's Anti-Japanese Military and Political College of short circuit block. B.

Reactor of installation reactor installation is actual be from exterior the internal resistance that increases transducer power supply source is fought. In the communicates side or transducer dc of transducer side installs reactor or install at the same time, can restrain harmonic electric current. C.

Transformer heterogeneous moves normally the rectification part of transducer is 6 pulse commutator, the harmonic that arises so is bigger. The heterogeneous that applies transformer moves, if make phase angle each other differs the Y of 30 ° - △ , △ - 2 transformer that △ combines are formed be equivalent to 12 pulse commutator, can reduce harmonic electric current, remove harmonic inhibition. D.

Adjust the carrier wave of transducer is compared than raising transducer carrier wave, can restrain effectively low second harmonic. E.

Applied filter filter can detect the amplitude of transducer harmonic electric current and phasic, produce phasic and as identical as amplitude of harmonic electric current, contrary electricity, be absorbed effectively thereby and eliminate harmonic electric current. Of 3 load match 3.

Fan of load of 1 square torsion kind, pump kind load is the equipment with industrial most field application, the transducer application on this kind of load is most. It is load of torsion of a kind of square. Usually, the transducer that has U/f ＝ Const to control mode can satisfy this kind of laden requirement basically, below the problem that notes according to the need when the main characteristic of this kind of transducer introduces type selecting. 3.

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1 avoid overload fan and water pump general not easy overload, the capacity that make sure its are more than a bit when the capacity that chooses transducer or is equal to electromotor can; The overload capacity demand of the transducer that chooses at the same time is inferior also, achieve 120 ％ commonly, 1min can. But choose in transducer function parameter and should notice when buy beforehand, because the square of laden block torsion and rotate speed becomes direct ratio, when the rated frequency of electromotor of working frequency prep above, laden block torsion can exceed rated torsion, make electromotor overload. So, want to control top job frequency strictly to cannot exceed electric machinery rated frequency. 3.

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2 open / the transducer when stopping quickens time and slowdown time because the laden moment of inertia of fan and pump is bigger,match, when its are started and stopping, with the acceleration of transducer time is mixed slowdown time matchs is a very serious problem. When transducer type selecting and application, should according to the acceleration of transducer of bear parameter computation time and slowdown time choose the shortest time, so that had not happened when transducer is started,shed the situation that overvoltage tripping operation does not produce when tripping operation and transducer decelerate. But in manufacturing technology sometimes, very strict to the requirement of the time that start of fan and pump, if afore-mentioned calculative time cannot satisfy requirement when, should undertake redesigning type selecting to transducer. 3.

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The 3 power source frequency that because transducer is to pass change electromotor,avoid resonance will change electric machinery rotate speed to achieve energy-saving result, coincide of frequency of the resonance dot with bear shafting, resonance falls likely in rotate speed of some electric machinery, cause the vibration with bear flagrant shafting, can cause equipment to stop carry or equipment breakdown sometimes, choose in transducer function parameter so and beforehand when buy, should the resonance frequency according to bear shafting, through set bouncing frequency is nodded and width, avoid appearance of systematic happening resonance. 3.

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4 hold back are pressed with pump of water hammer effect kind load is running a course actually in, incidental hold back is pressed and water hammer effect, so when transducer type selecting, want to have separate set in the light of this problem when functional set. A.

Hold back presses pump kind load moves in low speed when, because shut exit door to make pressure elevatory, cause pump cavitation thereby. When transducer function set, the lowermost frequency that passes demarcate transducer comes the rotate speed of critical point lowest of demarcate pump discharge, can avoid the happening of this kind of phenomenon. B.

Pump of water hammer effect kind load is in when cutting off the power suddenly, flow backwards as a result of the liquid gravity in pump conduit. If go against,stop a powerful person lax or did not go against stop a powerful person, will bring about electric machinery to invert, generate electricity because of electric machinery and make transducer malfunctions or burn out. When transducer system is designed, should make transducer stops by decelerate curve, disconnect again after electric machinery dead stop main circuit, or set " cut off the power decelerate stops " function, can avoid the happening of this phenomenon. 3.

Conveyer of belt of load of 2 constant torsion is the typical case of constant torsion load. The basic characteristic of constant torsion load is, in bear particular case falls, laden block torsion depends on the friction between leather belt and platen the radius of obstruction and platen. The speed of this kind of laden torsion and rotate speed has nothing to do, adjusting so in rotate speed process, laden block torsion keeps changeless. When constant torsion load is selecting frequency control system, besides asking by convention, the control way that answers transducer undertakes choosing. A.

The timing scope of bear. In timing scope not big case falls, choose relatively simple and easy V/F to control the transducer of means. When timing when range is very big, lv of take an examination uses the vector that has feedback to control fashion. B.

It is changeless that constant torsion load just issues laden block torsion in the circumstance with fixed negative charge, but when changing to bear, its turn be apart from still change along with bear. Change when torsion when range is not big, the V/F with optional relatively simple and easy choose controls the transducer of means, but the load with fluctuant to torsion bigger range, lv of take an examination uses the vector that does not have feedback to control fashion. C.

If load is right the demand of physical characteristic is not high, can consider to choose relatively simple and easy V/F to control the transducer of means, and asking taller circumstance, must use the vector that has feedback to control fashion. Above of 4 last words is an author the experience in transducer type selecting and application, consult when transducer choose and buy and application for concerning personnel. Change as the tall intelligence of transducer, case of high reliability, low and maintenance-free, transducer is energy-saving fall the effect of bad news will be more apparent. CNC Milling