Kemppi Minarc Evo 150 Service Manual

Also see for Minarc Evo 150: Operating manual

Kemppi Minarc Evo 150 Service Manual Manual pdf 12 page image

Service manual Minarc Evo 150 and 180 Version 1.3 30.9.201510Kemppi Oy3.4. Description of operationMinarc Evo 150/180 can be divided to two parts: Z001 main circuit card and A001 control/panel card Z001 main circuit cardo Input rectifier and PFC circuito IGBT moduleo Main transformero Secondary rectifiero Secondary chokeo Auxiliary switching power supplieso Current measuring A001 control cardo Inverter controlo Panel displayo Current set value adjustmento Panel buttons functionso Panel LEDso Remote control functions3.4.1. Z001 Main circuit cardMain circuit card; coil components and their functions: Main transformer turn ratio is 4:1; its primary winding is 20 turns (wire) and secondary5 (foil). Transformer has 140/170°C PTC for over heat protection. While temperaturerises the resistance stays under the 100Ω until the breakdown point (140°C), then thePTC goes to high-resistance mode (>10kΩ). Control logic stops inverter when theresistance value rises over the 1,5kΩ. Secondary choke L3 inductance is 5μH and its winding has13 turns. Choke slows thesecondary voltage changes and works as energy storage in the long short circuits. PFC choke works together with PFC circuit. It has 66 turns.Main circuit card itself provides the following functions: DC-link soft start charging and over voltage protection circuit. It avoids full powerconnection if the primary has a short circuit or main supply voltage rises over thesafety limit. EMC filtering circuit filters EMC disturbances from main supply voltage to machineand vice versa. The single-phase rectifier/PFC module rectifies the mains voltage (nominal 230VAC)to PFC circuit, approx. nominal value of 320VDC. Rectifier holds four power diodes.PFC circuit is integrated in the same module with rectifier diodes. PFC circuit (twoparallel IGBTs, two diodes in series and PFC choke) keeps the primary voltage andcurrent in the same phase. This rises the power factor up to 0,99. PFC is boost typeand raises the DC-link voltage up to 390VDC. Power section is based on dual forward architecture with 63 kHz switching frequency.It has two stages: ON and OFF/demagnetizing. OFF-stage must last longer time thanON-stage because main transformer needs to be demagnetized. Otherwise it goes tosaturation.