Cut-off, operation and discharge resistors

Starting and braking resistors are widely used to control motors during starting and/or stopping. The starting current of asynchronous motors may be 4-6 times the nominal current. Starting resistors are used to limit these high currents. Lever control is a very common application for braking resistors. While descending, a load, especially if heavy, may cause the engine to generate power as if it were lifting. Hence resistors are used to avoid unwanted and uncontrolled acceleration. Disturbing large capacitors and inductors should be done with caution to avoid surge currents that could damage them permanently. Discharge resistors limit the peak current and protect the capacitive/inductive device.