Re: Dessalator Duo watermakers - energy saving tip: don't use 230v if you can avoid it

Oliver Henrichsen, SV Vela Nautica


We got the same Duo 100.
It was compleatly falling apart after only 300h of use when we got Vela Nautica. 
We gave it a compleat refit what included an one DIN grade stronger AC Motor because CAT PUMP Germany said the build in AC Motor is not strong enough. And the motor shaft was worn out. 
It was also needed to replace the soft pulley discs to industrial grade ones and change all bearings to high quality SKF. 
The selenoid previously munted on the device did not cope with the units vibrations and was then wall mounted. 

Since that its working flawless and has now about 900 hours. The unit is now almoast vibration free and is not to be heard anymore.

We use AC only when the Genset is working anyway. Otherwise we use the 24V motor. We like this oportunity to switch AC / 24 V, I think its a clever design. Only it might be wise to use higher grade spares than the original brand. 

An replacement of the 220 V AC motor is not really expensive (industrial grade about 160 €) so its not worth to level motor wear. 

Oliver from Vela Nautica Amel54#39 

On Tue, Jun 30, 2020, 16:29 Scott SV Tengah <Scott.nguyen@...> wrote:
We have a Desslator Duo 100 that runs on either 24v DC or 230v AC.

According to the specs and our own measurements, the 24v motor draws 600watts and the 230v motor draws 1100watts! The AC motor draws 83% more energy, so I asked Desslator if it produced more water per hour. Here's their response:

"It is the pulleys ratio which make both motors turn at the same speed at the axis of the pump, even if the electrical consumption is more important with the AC motor.  

Consequently, both motors produce the same liters per hour (around 100 liters with a 25° sea water)."

I've been trying to "balance out" the motor wear by using both DC and AC, as I'm acutely aware of the problem of DC motor brush wear on my fridge pumps. But it seems if you're trying to do your part to save energy, running the AC motor is not a good idea.

Related question - what are people's experiences with DC and AC motor longevity. My research on DC motor brushes seems to indicate 2000-3000 hours of life is typical. What about the AC motor? I recall hearing the capacitors being the first things to go?

2007 A54 #69
SV Tengah

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