Preparing the workshop…
This is the British Bombe
During World War II, British codebreakers used the Bombe to find the daily settings of German Enigma machines. It tested rotor positions against a guessed word from an intercepted message, called a crib, and stopped where the crib could fit.
History of breaking Enigma- Chain 1: The top row of 12 scramblers. Each scrambler has three drums that copy the rotors of one Enigma.
- Left rotor: The top drum of each scrambler does the job of the Enigma’s left rotor. A motor turns all 36 top drums together.
- Middle rotor: The middle drums stand for the Enigma’s middle rotor. They move on one letter after each full turn of the top drums.
- Right rotor: The bottom drums stand for the Enigma’s right rotor. They move on one letter after each full turn of the middle drums.
- Chain 3: The bottom row of 12 scramblers. Each of the three rows has its own reflector connector, chain switch and test-current switches.
- Chain switches: One on/off switch for each of the three chains.
- Power switches: Two switches above the letter box. The operator turns both on before a run.
- Letter box display: When the Bombe stops, it shows the plugboard partner of the test letter. The lever on its left restarts the Bombe.
- Indicator drums: Three gold drums that show the drums’ position. When the Bombe stops, the operator reads the rotor positions here.
- Start and stop buttons: The left button starts the Bombe and the right button stops it.
- Current injection switches: One switch per letter for each chain. The operator chooses which of the 26 wires receives the test current.
- Carry options: Switches for the carry, which moves the middle drums on after each full turn of the top drums. Carry home returns every drum to its start.