Question about the refrigiration system on an A54


Arno Luijten
 

Digging deeper and deeper in the engine bay, I found something I don’t really understand. Maybe the esteemed members of the forum can enlighten me.

The refrigiration system has a electronic box that senses if any of the fridge-compressors is running. If so it activates the sea-water pump to push cooling water through the systems. Now this box indicates 12 or 24 volts and the 24 volt LED lights up. So far so good. Now why are the actual pumps (main and spare) 12 volt? And where is the converter that supplies the 12 volt for the pump?

Thank you all for taking the effort to read my query!

Arno Luijten

Luna, A54


John Clark
 

Hi Arno,
Just a guess on my part, but some equipment can accept a variety of input voltage/frequency and rely upon an internal converter to provide the load with correct power. Case in point is the new compressor I just installed for the salon frig-freezer. It can utilize 12 to 36 volts DC as input and provide the motor with variable frequency A.C. at a higher voltage. All internal.

Regards John

SV Annie SM 37
Le Marin


Arno Luijten
 

So, for those interested:
I looked it up on the Interweb and is seems Frigoboat (actual company name is  Veco S.p.A.) has this system where they use a special developed circulation pump designed to run 24/7. Apparently they did not want to develop a 24 volt version so they only have a 12 volt version. To accommodate a 24 volt ship's system they have some devices (like the pump switch) to lower the voltage from 24 to 12 volt. The compressor and such still runs on 24 volt as this is the standard Danfoss system that can accept both 12 and 24 volt.
So the switch (http://www.penguinfrigo.co.uk/shop/product/581/) itself converts the 24 volt into 12 volt to supply the pump.

The tricky part is that this pump has a fairly low consumption (1Amp. @ 12 Volt) and this pump should not be replaced by just any other pump, given it's duty cycle and noise level.
I'm actually wondering if this is not just a 24 volt pump set to rum at 12 volt to make it last longer and more quiet.
Amel 54's come equipped with a spare pump right next to the active one. There is a reason for this.

Arno