High frequency oscillation be close to switch to be magnified by ﹑ of unit of demodulation of detecting element ﹑ unit ﹑ is rectified model the composition such as unit and output unit. The detecting element that interior of this kind of sensor installs is by check line circle and high frequency oscillator are comprised, generation of ring of line of the check after appending report makes the electromagnetism field that change, when metallic object is close to electromagnetism field, the magnetic flux density of metallic surface produces change and generate faradic —— vortex flow. The magnetic flux way that eddy current produces unripe magnetic flux to always measure coil with check is opposite. As a result of the action of eddy current, make check line encircles specific power consumption to increase. Character coefficient drops. Amplitude is reduced, down to oscillator stops brace up. Conversely, be far from this effect zone time when metallic thing. The oscillator begins oscillation again. Detect circuit detects amplitude implement after condition changes, changeover measures question mark for a switch.

 

 

Be operation method must notice when use, the thing that concerns with report after all is more dangerous. The positional sensor that is close to switch to belong to a kind to switch measures output is inductance type and capacitance type according to the different cent of working principle, inductance type is close to switch it is comprised by LC high frequency oscillator and enlarge processing circuit, use metallic object to be when the oscillation induction head that approachs this to be able to produce electromagnetism field, make object interior generates vortex flow. Can need to be made according to the client high temperature resistant model be close to switch, highest temperature 150C.

 

Alternating current source receives rectification module, classics filter affects three-phase becomes dc after complete wave commutator, receive return of high frequency inversion again, dc changeover is high frequency communicating, final classics outputs smooth dc after bridge of high frequency transformer, commutate, filter.

 

Circuit of high frequency switch is main by circuit of rectification filter wave, circuit of complete bridge commutation, PVm is spatio-temporal make circuit, circuit of stabilized voltage, voltage limiting, circuit of steady flow, current limliting, protect circuit, and the composition such as circuit of auxiliary power source.

 

Three-phase electrified wire netting (or single-phase) voltage classics after mains switch, have rectification filter wave, gotten 520Vdc (is single-phase the circuit of inversion of supply of flowing volts d.c. that is 300Vdc) . .

 

Inversion circuit is main by high-power IGBT module (or module of field effect MOSFET) circuit of commutation of compositive complete bridge. Give control signal to part through keeping apart driver when Yu of P make tea drive power module, two groups of diagonally canals guide alternately respectively, in high frequency transformer primary generation is high frequency pulse voltage, sub voltage provides energy to load by commutate of the classics after transformation of high frequency transformer.

 

Output end is received respectively have the feedback circuit such as stabilized voltage, current limliting and steady flow, voltage limiting. When condition of park stabilized voltage, stabilized voltage and current limliting circuit are effective, when when output voltage lifts or dropping, sampling voltage passes comparator of voltage of interior of firm jade circuit to be compared with fiducial voltage, voltage of its error signal adds circuitry of the control when Pw, make PV Yu gives arteries and veins wide make corresponding change, stabilize output voltage thereby, if load current is exorbitant when, current limliting circuit works, make output voltaic limitation to be inside value of current limliting set.

 

Same, below steady flow condition, action of steady flow circuit, make output voltaic stability to be inside set value, and when be pressed too, voltage limiting circuit makes output voltage clamp be worth in voltage limiting. Should have unusual case (if the input passes to press or be owed,press, flow too or overheat) when generation protects signal to add protection to dominate circuit, protective circuit is outputted – a voltage adds PVM circuitry, make PM circuit stops to output, achieve protective goal thereby.