6. Braking rheostat

It is widely used when the supply network is not suitable for regenerative braking, and is a natural choice for autonomous traction.

Its characteristic is the ohmic value r, which determines the power to be dissipated:

Commonly achieved values range from 800 kW to 2,400 kW.

Depending on the resistance material chosen, generally a nickel-chromium alloy ribbon, we determine the thermal power not to be exceeded and the ventilation to be provided. There are two main types:

• natural convection, propeller-type rheostats, often roof-mounted. Their operating temperature is between 400 and 600 ˚C, 1,000 ˚C in exceptional overload. They are...