9 5 0 B O P E R A T O R S S T A T I O N
E L E C T R I C A L T R O U B L E S H O O T I N G
I n d u c t a n c e
Damage to a switch can be prevented by the connection of a diode across the
inductance in the reverse direction. This diode does nothing during normal
operation of the coil since it is connected so that its cathode is at a higher voltage
than its anode and no current flows through the diode.
D i o d e P r o t e c t i o n
When the switch suddenly opens, the coil becomes a source of voltage in order to
keep its current flow. At this time, the diode is able to conduct because its anode
is positive in relation to its cathode. Current flows through the coil and diode
until the energy of the inductance (coil) is used up. The switch is not damaged.
F l y w h e e l E f f e c t