POLARISATION RECTIFIERS

Chemical Processes often have large power rectifiers as their primary source of DC Power. If these rectifiers are turned off, either for maintenance or a malfunction, there is a danger to the hardware of the chemical process. To solve this problem, standby rectifiers are installed in parallel with the main rectifiers. These rectifiers, known as Polarisation Rectifiers, pass electric current through the process and prevent damage. As these rectifiers are used as stand by, they have to be extremely reliable.

During start-up of the electrolyser, as the main rectifier is off, the PR supplies current to the electrolyser, and continues to supply the current as long as the output voltage of the main rectifier is less than the voltage of PR. The moment the main rectifier voltage is equal to the PR, the PR supplies current equal to or less than the set point current During normal operation this unit operates in parallel with the main rectifier supplying rated current each polarisation rectifier consists of 2 rectifiers which are designedto operate in parallel redundant mode, A third rectifier known as the Booster rectifier may also be used.