High-pressured transducer is basic intellectual introduction

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The source of Com1, voltage distinction with transducer of current source high pressure. The main circuit substantially of transducer can divide it is two kinds: Voltage source with current source model. Voltage source it is the transducer that is the dc commutation of voltage source communication, the filter wave component of dc loop is capacitance; Current source it is the transducer that is the dc commutation of current source communication, its spread cell of loop filter wave continuously is inductance. 2, why the output voltage of transducer and frequency proportionate change? Between the electric current that has flowed inside the magnetic flux that the torsion of asynchronous electromotor is electric machinery and rotor interaction and of generation, below rated frequency, if tension is constant and reduce frequency only, so magnetic flux is too big, magnetism loop is saturated, electric machinery electric current increases, serious when burn down electric machinery. Accordingly, frequency and voltage want to be changed into scale ground, change the output voltage that transducer controls while frequency conversion is led namely, make the magnetic flux of electromotor keeps certain, avoid the generation of magnetism saturation phenomenon. This is the definition of VVVF. The line voltage that what the voltage here points to is electric machinery or the virtual value of phase voltage. 3, when electromotor uses drive of labour frequency power source, voltage drops an electric current increase; To transducer drive, if frequency drops when voltage also drops, so whether does electric current increase? Frequency drops (low speed) when, if output same power, criterion electric current increases, but in torsion certain condition falls, electric current is almost constant. 4, when using transducer to run, the starting electric current of electric machinery, starting torsion how? Use transducer movement, heighten frequency and tension accordingly as the acceleration of electric machinery, starting electric current is by limitation under 150% rated electric current (basis machine kind different, for 125% ～ 200%) . When power source of the frequency that use worker worker starts directly, starting electric current is 6 ～ 7 times, accordingly, will produce machine electric the concussion that go up. Use transducer drive to start smoothly (starting time lengthens) . 1 what starting electric current is rated electric current.

2 ～ 1.

5 times, starting torsion is 70% ～ 120% rated torsion; Enhance functional transducer automatically to containing torsion, starting torsion is 100% above, can take full load to start. 5, what meaning is V/f mode? V of the voltage when frequency drops also drops into scale, this problem already was answering 4 specifications. Maintain V/f to compare constant the most fundamental control pattern that control is frequency control of asynchronous electric machinery, it controls the voltage that transducer outputs while the power source frequency that dominates electric machinery changes, make of both it is than V/f constant, make the magnetic flux of electric machinery keeps constant thereby. In electric machinery rated moving circumstance falls, the voltage drop that the stator resistor of electric machinery and leakage resist is smaller, the carries voltage and electric machinery reaction electromotive force of electric machinery is approximate and equal. V/f comparing is constant the main problem that controls existence is low speed function poorer. Its reason is what voltage drop of resistor of stator of electric machinery of the asynchronous when low speed occupies scale to greaten, already cannot oversight, cannot think stator voltage and electromotive force of electric machinery reaction are approximate and equal again, still control magnetic flux of irretentive already electric machinery certainly by V/f comparing constant. Of electric machinery magnetic flux reduce the electromagnetism torsion that causes electric machinery necessarily; Additionally the dead band time of transducer power parts of an apparatus also is the main reason that affects performance of electric machinery low speed, dead band time causes voltage to drop to still can cause torsion at the same time pulsatile, the oscillation that can cause rotate speed, electric current is returned below certain condition. V/f comparing is constant control is commonly used go up at general transducer. This kind of transducer basically is used at the timing function of fan, water pump, and not tall to timing scope requirement circumstance. V/f comparing is constant pilot stresses a good point is the control of open loop speed that can have electric machinery. 6, when changing V and F in proportion, how does the torsion of electric machinery change? Tension is reduced into scale ground completely when frequency drops, so as a result of communication impedance decrescent resistor is changeless, will cause the torsion that arises below low speed to have reduced liability. Accordingly, v/f is given when low frequency, should make output voltage to rise a few, so that obtain certain starting torsion, this kind of compensation says to increase start. Can use all sorts of method implementation, have the method that has automatically, choice V/f mode or adjust the method such as potentiometer. 7, what meaning is alleged open loop? Give rate of uses electric machinery furnish sensor, actual rotate speed feedback has pilot to control equipment, call " closed circuit " , need not speed sensor runs cry " open loop " , general transducer is open loop means more. 8, the overload of protective function output of high-pressured transducer oneself, output flows too, under-voltage of overvoltage of electrified wire netting, electrified wire netting, electrified wire netting breaks overheat of under-voltage of generatrix of overvoltage of generatrix of report, dc, dc, transformer, be short of power source of photograph, control to drop report, overheat of parts of an apparatus of drive breakdown, power. CNC Milling CNC Machining