Wednesday, Jan 15, 2020 at 14:22
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Hi RMD, Engel do some unorthodox things in their circuitry and some, if not all, of their units produce a square half-wave dc then pass it to the 'motor' via a capacitor to create full-wave ac. The fan is connected across the capacitor which provides a nominal 24vdc. There is no conventional rectification to supply the fan. I am never comfortable with such circuits even if they do work.
If his 'compressor motor' is running and his fan runs on
test then the capacitor I referred to must be intact so maybe his model uses a rectifier instead and it is faulty. Who knows? It is very hard to get technical info on Engels.
There can be a problem sometimes with placing 12v brushless computer fans in series. Not always maybe, but sometimes. Each fan relies upon its current to flow through the other fan and as they operate by 'chopping' the dc the current path is not contiguous which causes upsets. They can get very confused! Note that this may not apply to all 'computer' fans but I have encountered it twice. Wondered what was happening when each fan would rapidly get a burst of power then coast in turn.
Nick may do better to use his existing 24vdc fan connected to the Engel 'motor' via a
bridge rectifier but as I said above, he may need to trim the fan voltage.
My own Waeco has been retrofitted with two fans but not in series.
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