Harwich Radio Direction Finder (RDF) tower was fitted with this diesel generator when it was built in 1941. This was to ensure an uninterrupted power supply should bombing cut mains power. It also allowed the tower to remain active should invaders disrupt an external supply. It was thought that the generator present today was the original, used to power the equipment during WWII. Unfortunately, the serial number AA1 found on the data plate actually dates the generator to sometime between 1964 and 1992.
When originally built, this room was separate from the other rooms in the tower. The door through which you entered only served the generator room.
When you are ready to move to the next room look closely at the bottom of the opening as you walk through. You will see that the lower courses of bricks have been cut away as this doorway was formally a square service hatch, the remains of the hinges and latch can be seen on the original wooden frame.
Technical Information
The original generator ran at 3000 revolutions per minute (RPM), 50 cycles per second (50 hertz), this is the same as mains electricity.
Although it is not large or powerful, its output could be stepped up to a peak of 15 kilowatts (15,000 watts). An average electric fan heater uses between 1500 and 2000 watts. This power was produced by passing the output of the generator through a transformer.
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