③ electric wave disturbs: Accusation makes cable make antenna, electromotive force arises in cable by ab extra electric wave.
measure: Narrate with 2 with 1. Put transducer iron when necessary electric wave screen has inside box, the iron case that screen uses wants ground contact.
④ contacts undesirable interference: The electric contact that shows transducer controls cable and relay touch point contact undesirable, resistor produces the interference that change generates in cable.
measure: To relay contact is contacted undesirable, use shunt-wound contact or aureate contact relay or choose sealed type relay. To cable join dot should be done regularly screw consolidate is handled.
Conducted interference of ⑤ power supply cord: When showing all sorts of electric equipment obtain power supply from system of same power source, produce electromotive force directly in power source system by other equipment.
measure: The control power source of transducer by additional systematic power supply, filter of side furnish circuitry is inputted in what control power supply; Furnish insulation transformer, and screen ground connection.
⑥ ground connection disturbs: Point to airframe ground connection and signal ground connection. The interference that all sorts of expect that reach any unreasonable ground connection to all can be caused to loop of weak voltage electric current are less than, install two above ground connection to nod for instance, ground connection place can produce voltage, generation interference.
measure: Speed is given control cable takes 1 to nod ground connection, the access of signal of ground wire nonfeasance is used. The ground connection of cable undertakes in transducer side, use the earthing terminal that sets only, as not common as other earthing terminal, reduce earthing terminal to cite the resistance of contact as far as possible, do not be more than 100d commonly.
of 3) other note
The ① control of transducer ark, answer to be far from high capacity transformer and electromotor as far as possible. Its control cable road to also should keep away from the facility with these leakage large magnetic flux.
Cable of control of electric current of ② weak voltage is not close to the breaker of easy generation electric arc and contactor.
③ control cable suggests to use 1.25mm × 2 or 2 screen of 2mm × are wrung add up to insulated cable.
The screen of ④ screen cable should grow likewise to cable conductor continuously. Cable is in in terminal box when join, screen terminal wants coadjacent.
4 transducer is common breakdown analyses
1) transducer charges of starting circuit breakdown
general transducer is voltage transducer commonly, use hand in, straight, hand over a completed project makes way, it is the input is alternating current source namely, volts d.c. turns into after commutate of bridge of commutate of alternating voltage three-phase, next commutation of circuit of inversion of bridge-type of three-phase of volts d.c. classics is pressure regulating the three-phase alternating current of frequency modulation outputs load. When transducer firm electrify, the size of smooth wave capacitance as a result of dc side is very large, charging current is very big, use a starting resistor to restrict charging current normally, common frequency conversion starts two kinds of circuit, if pursue, 1 place is shown. Charge after finishing, control circuit passes the contact of relay or brilliant brake is in charge of resistor short circuit, average performance is starting circuit breakdown starting resistor is burned-out, transducer calls the police show for breakdown of dc generatrix voltage, when general architect is designing the starting circuit of transducer, to reduce the volume of transducer the choice starts resistor, choose a few smaller, resistance is in 50 Ω of 10 ～ , power is 10 ～ 50W.
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