Fire control is electrical, using a 27v DC system.

For further information on the DC system, refer to Section 6.

Entry of modules and formal approval must still be performed in the normal way via the DC system.

After arbitration by the Board of Trade the DC system was taken up.

Now, in a DC system, the voltage and current, in the steady state, are not changing, so the power is constant.

In the 3N series, a non-insulated DC three-rail system was used to power the engines.

The DC system incorporated a lead acid battery and operated in a conventional manner.

As is common with DC systems, the negative pole is grounded.

The DC electrical system is attached to the mains via this mechanism.

The DC system is quite simple but it requires thick cables and short distances between feeder stations because of the high currents required.