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Variable Ratio Transformer Technology in oil/water cooling


Electrolytic strip galvanizing, Plating Processes, High-current Applications

Product Description:

The robust Variable Ration Transformer Rectifiers in water/oil cooling are designed for reliable operation in the harshest environments. All critical power components are completely submerged in oil so the best protection from the environment is guaranteed.

The complete power unit is integrated in a plain sheet tank filled with insulating oil. The internal heat loss is completely discharged via the customer-provided cooling water by means of a circulation pump and an oil-water-heat exchanger. This concept provides an outstanding basis for energy-efficient approaches.

Due to the high water inlet temperature of up to 45 °C a return temperature of up to approximately 60-65 °C would be possible. With the MUNK oil water cooled Rectifiers waste heat can be sustainably used.

Our Variable Ratio Transformer Technology is also available in oil-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 / water cooled Variable Ratio Transformer Technology is preferably used for output ranges from ≥ 3000 A - 15000 A. Due to the compact design and the high protection grade (IP 54) an installation in direct proximity of the process is possible.
Oil/Water cooled DC Power Supplies in Variable Ratio Transformer Technology are equipped with a sustainable heat recovery system to reduce energy costs.

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


The Variable Ratio Transformer Rectifiers in oil/water cooling are availabe in the following tank sizes:

(Dimensions in mm)

TypWidthDepthHeightOil 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 operating commands
Analog Voltage Values 0-10 VDC
Option: 4..20 mA, Profibus DP, PROFINET, etc.

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