I bought a small 720 Watt petrol generator while i was living and working in Dublin. I got fed up with the frequent power cuts, on two occasions in 2009 they were caused by the underground cable under the street melting due to overloading and poor or illegal connections. On both occasions the power cuts caused damage to electrical equipment, on one occasion to CCTV equipment and on another to PC and network equipment. In the summer of 2014 the power to my mums caravan failed due to a local fault with the supply on the site. As it took over 36 hours to fix the problem i decided that it was time to press the generator into service so as not to be caught out again. Although there was no physical damage to equipment this time some caravan owners who left their electricity switched on while away found that there were a few nasty smells coming from their fridges on their next visit!
I had to buy a 16 Amp Industrial socket which cost just a few pounds to connect the caravan to the generator. The generator outputs it's power via a standard 13 Amp UK three pin socket.
So a simple cable allowing the generator to be connected to the caravan had to be made. A spare 13 Amp three pin plug and some spare 13 Amp 3 core flex was used to make the cable.
In this photograph the cable has been passed through the water proof gland and the cable ends prepared for connection.
In this photograph the three cores of the cable have been connected to the screw terminals on the rear of one half the connector and the strain relief bracket has been fitted.
A multimeter was used to check the continuity of the connection from each pin of the 13 Amp plug to the corresponding pin of the 16 Amp plug.
This photograph shows the completed cable assembly. The cable has been kept as short as possible to minimise power losses along its length but long enough to allow the generator to be sighted so that it is not too noisy and to minimise the danger of fumes drifting into the caravan.
This photograph shows the cable connected to the generator and in turn to the caravan via the 16 Amp Industrial connectors.
The generator was started with the switch in the consumer unit in the off position. The switch was then moved to the on position and then the generator gradually loaded up by switching on the lights and then the fridge.
TV, computer and satellite equipment was not connected due to warnings about the quality of the sine wave output from the generator that may damage sensitive electronic equipment.
To check the quality of the sine wave output of the generator i connected a pocket oscilloscope to the generator while it was under a load of approximately 300 watts.
The photograph shows the output of the generator. The voltage level is good however there is a slight distortion on each half of the cycle. This is due to 'crosstalk' from the magneto ignition system when the magnet passes close to the generator windings. Searching the internet forums for this type of generator it is easy to believe from the reports that connecting any piece of sensitive electronic equipment to it will result in instant destruction. The waveform does not look as bad as some people claim can be produced by these generators but better to be safe rather than sorry.
Before connecting sensitive equipment to the generator i will check the waveform currently available from the local mains supply and compare it to the one produced by the generator.
Further information on testing to follow at a later date.........