Error one: In transducer output loop joins contactor of electromagnetism switch, electromagnetism is in actual application, a few circumstances need to use contactor to undertake transducer switch: If become,the switch when frequency conversion breakdown moves to labour frequency condition, or it is to should use lug 2 means, an electromotor breakdown, transducer changes direction procrastinate change the condition such as another electromotor. So a lot of users can think to output loop to add contactor of outfit electromagnetism switch, electromagnetism in transducer is standard configuration, it is the kind that brings full disconnection power supply, in fact the hidden trouble with bigger presence of this kind of practice. Malpractice: When transducer still is moving, contactor go ahead of the rest disconnects, interrupt load suddenly, surge electric current can have made electric current protects a movement, can produce certain impact to rectification inversion main circuit. Serious, can make transducer outputs module IGBT to cause damage even. In the meantime, when taking perceptual electromotor load, energy of perceptual magnetic field cannot be released quickly, will produce tall tension, injure the insulation of electromotor and join cable. Answer strategy: Output transducer side to be linked together with electromotor cable directly, it is OK to have power cut intention normally through sparking transducer control terminal comes true, achieve soft case soft the effect that stop. If must be in frequency control implement output side uses contactor, must be in frequency control implement between output and contactor movement, try necessary control is interlocking, assure to be in only frequency control implement when having output, contactor ability movement. Error 2: When equipment halts use normally, disconnect when transducer communication inputs power source to halt use normally in equipment, a lot of users are used to disconnecting transducer communication inputs mains switch, think in that way OK also and safer, energy-saving. Malpractice: This kind of practice, can rise to protect transducer not to suffer effect of percussive of power source breakdown it seems that apparently. Actually, transducer is long not electrified, add effect of spot environment humidity, can cause interior circuit board be affected with damp be affected with damp and produce slow oxidation, appear gradually short circuit phenomenon. This cuts off the power in transducer namely after period of time halting use, meet when power transmission again the reason that signs up for soft breakdown often. Answer strategy: Outside be being overhauled except equipment, should make transducer is in electrified condition for long. Besides, still answer the fluctuation fan of ark of control of open frequency conversion, desiccative is placed inside ark or install automatic temperature and humidity to control heating apparatus, keep ventilated with the environment dry. Error 3: The transducer that installs below open air or dust environment controls ark to use sealed type to install use transducer to control ark in partial mining plant, basement, open air, can undergo the astringent test that waits for harsh environment like high temperature, dust, moisture. For this, a lot of users can choose the frequency conversion ark of sealed type. Although can rise on certain level,prevent rain, dustproof effect so, but also brought transducer to come loose at the same time the problem with bad heat. Malpractice: Control ark is sealed tight can make because transducer is ventilated come loose to heat energy force is not worth and cause interior yuan overheat of parts of an apparatus, heat quick component protects a movement, create breakdown tripping operation, equipment is forced to halt use. Answer strategy: In transducer control ark upside is added install the cover preventing rain that breathe freely, and contain dustproof mesh, serve as vent at the same time. Bottom opens groove to install the fan that brings mesh as much, as the mouth that take energy of life. Can form airiness, the dust in the environment filters in the meantime. Cooling air is current direction: Flow to coping from bottom. The transverse installation distance between transducer should not be less than 5mm, the cooling air temperature that enters transducer cannot exceed + 40 Celsius. If environmental temperature is in for long + 40 Celsius above, need to consider to be transducer installation inside air-conditioned closet. In controlling box, transducer should be installed commonly in casing upside, do not allow a calorific component absolutely or easy the bottom installation that calorific component relies on transducer closely. Error 4: To improve voltage quality, in transducer output carries shunt-wound power factor to because be restricted with capacitance,compensate capacitor part company, voltage character cannot get safeguard, especially the large facility that use phone is cast when using, can cause voltage of the generatrix inside plant station to reduce, laden power factor is obvious as drop. To improve voltage quality, the user carries shunt-wound power factor to compensate capacitor in transducer output normally, the hope can improve electromotor power factor. Malpractice: power factor compensation capacitor and surge are absorbed implement join is on electric machinery cable (between drive unit and electric machinery) , their influence can reduce the control precision of electric machinery not only, still can output side to form twinkling to change in drive unit voltage, cause the permanent damage of ACS800 drive unit. If factor of power of the paralell connection on the line is inputted to compensate capacitor in the three-phase of ACS800, must ensure this capacitor and ACS800 won't charge at the same time, in order to avoid transducer of surge voltage attaint. The electric current of transducer flows into the capacitor that improves power factor to use, as a result of its charging current causes transducer to pass electricity (OCT) , cannot start so. Answer strategy: the movement after capacitor is demolished, as to improvement power factor, it is effective that in the input of transducer side receives AC reactor. Error 5: Choose breaker to heat up overload and short circuit protection as transducer, the effect compares fuse good breaker to have relatively perfect protection function, apply extensively already in distribution facilities, have the tendency that replaces traditional fuse greatly. The equipment of whole set frequency control that a lot of manufacturers produce now, basically also configure breaker (air switch) , actually this also is put in a few safe hidden trouble. Malpractice: Short-circuit in power source cable when breakdown, breaker protects behavioral tripping operation to produce delay time as a result of the inherent movement time of breaker itself, transducer interior can introduce short-circuit current during this, cause component damage. Answer strategy: Wanting cable only is a basis of type selecting of rated electric current, transducer drive unit can protect end of oneself, input and electric machinery cable, in order to prevent hot overload, do not need add and additional hot overload to protect facility. Configuration fuse will protection can fall to input cable in short circuit circumstance, decrease to device damages and prevent to be linked together when gearing interior short circuit the attaint of equipment. Check the fuse movement time of configuration to answer under 0. 5 seconds. Behavioral time depends on fuse type (GG or AR) , the cross section of cable of impedance of power supply network, power source is accumulated, material and length. Exceed when use GG fuse 0.
When time of 5 seconds movement, fast frit (AR) an acceptable level can reduce behavioral time below most circumstance. Fuse must is without delay time type. Breaker cannot be offerred to transmission enough fast protection, because their response rate is slower than fuse. When accordingly need is protected quickly, should use fuse and not be breaker. Error 6: Transducer type selecting needs to consider laden power only when a lot of users are purchasing transducer, match transducer capacity normally only according to the power of drive electromotor. Actually, the load that electromotor place drives is different, different also to the requirement of transducer. Malpractice: The difference of load performance existence that takes as a result of electromotor place, if consider integrated factor inadequately, may cause transducer to use undeserved and attaint, because did not deploy necessary apply the brake,at the same time unit is mixed filter, may pose safe risk. Answer strategy: Be aimed at laden character and type, reasonable the capacity that chooses transducer and configuration. 1) fan and water pump are prevailing load: Most simple to the requirement of transducer, want transducer capacity to be equal to electromotor capacity only can (the musical fountain of pump of pneumatics machine, deep water, silt pump, rapid change needs to increase a size) . 2) crane kind laden: This kind of laden characteristic is the concussion when starting very big, because this requirement transducer has certain surplus. In the meantime, in ancon of clog transfer to a lower level, can energy is passed on, because this wants,use unit of apply the brake or use common bus means. 3) all do not go laden: Some load sometimes light, weigh sometimes, the case that should record according to heavy burden right now will choose transducer capacity, for example rolling mill machinery, disintegrator instrument, mixer. 4) big inertial load: The whirl that is like plant of centrifugal, punching machine, cement kiln, this kind of load is inertial very big, when be being started accordingly may oscillation, electromotor decelerate from time to tome energy is passed on... should be accelerated with the transducer with largish capacity start, avoid oscillation. Cooperate unit of apply the brake to eliminate an electric energy of make a present of. 2, epilogue transducer consists other intelligence equipment (system of PLC, DCS) after cooperating, can realize multiple control strategy and closed circuit to adjust, its itself also has relatively perfect protection function. But in applying actually and installing an environment, put in a lot of errors however. Face up to contradictory place, avoid risk, reasonable apply, just be the key that improves transducer efficiency and service life. CNC Milling