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Variable Ratio Transformer Technology in oil cooling


Sub-contract plating workshops, Chrome processes, Special Applications

Product Description:

The enduring oil-cooled variable ratio transformer rectifiers give the best protection possible without the need of any external cooling source. All critical power components are completely submerged in oil, so optimum cooling and protection from the environment is guaranteed. The adjustment of the rectifier can be carried out by means of a motor-driven variable ratio transformer or electronically via analog signals for constant voltage and current control. The rectifiers offer a constant ripple of < 5 %.

Our Variable Ratio Transformer Technology is also available in oil-water-cooling.

Block diagram / Functional Description:

Capacity adjustement is achieved on the primary side. Using fuse elements and a main contactor ensures safe mains separation. Galvanic mains separation is achieved by the main transformer. A 6-pulse rectification meets the requirements which are relevant to the process. The main components (variable ratio transformer, main transformer, diode bridge) are installed in one steel tank.

Customer Benefits:

The oil cooled Variable Ratio Transformer Technology is preferably used for low and medium output ranges (1000 A - ≥ 15000 A)
Easy to handle and perfect for harsh everyday industrial conditions Variable Ratio Transformer Rectifiers are highly regarded worldwide.

Technical Data:

Mains Voltage:3 x 400 V, 50 Hz + N + PE
Output Current> 1000 A - 15000 A
Output Voltage:6 V - 150 V
Ripple:approx. 5 % full range
Duty Factor:100 % (24/7)
Efficiency:80 % - 93 %
Ambient Temperature:+ 35 °C, > 40 °C (Option)
Protection Grade:IP 54 tank / IP 23 cover


Variable Ratio Transformer Rectifiers in oil cooling are available in the following tank sizes:

(Dimensions in mm)

TypeWidthDepthHeightOil requirement
F18104901120160 kg
F29505701210210 kg
F311505801320290 kg
F412706101620440 kg
F513306701620460 kg
F613707101570480 kg
F714307701590500 kg
F815408001590580 kg
F915808801640660 kg
F10170010001640710 kg
F11205011301740930 kg
F122150118018901150 kg
F131920161020601850 kg
F142480148021702750 kg
F152600160021702900 kg
F162700170021702960 kg
F172800210021704100 kg
F182950210024204830 kg


Digital high/low operation commands
Analog voltage values 0-10 VDC
Option: 4..20 mA, Profibus DP, PROFINET, etc.

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