Maintenance 165 Reduced runA “reduced run” function is available for supply and inverter units consisting of parallel-connected modules. The function makes it possible to continue operation with limitedcurrent even if one (or more) module is out of service, for example, because ofmaintenance work.In principle, reduced run is possible with only one module, but the physical requirements ofoperating the drive still apply; for example, the inverter modules remaining in use must beable to provide the motor with enough magnetizing current.Activation of the reduced run functionWARNING! Obey the instructions in chapter Safety instructions. If youignore them, injury or death, or damage to the equipment can occur.Refer to the drawing below. The drawing represents the inverter unit, but the procedure issimilar for the supply unit.1. Stop the drive and do the steps in section Electrical safety precautions (page 19)before you start the work.2. Remove the shrouding above the module bay.3. Remove the DC busbar assembly (along with fuses) above the module. Store theseparts – they are to be reinstalled only with the module. Make note of the order ofwashers.4. Remove the faulty module from its bay according to section Removing the invertermodule(s) (page 111).5. Install the air baffle (included) to the underside of the top module guide:• Fasten the front edge of the baffle to the module mounting holes using the modulemounting screws (2 × M8). Tighten to 9 N·m (6.6 lbf·ft).• Fasten the left/right sides of the baffle if wherever possible using M4 screws. (Thisdepends on the location of the module in the cubicle.) Tighten to 1…2 N·m(0.7 … 1.5 lbf·ft).
