Fridges

[HaraldS]

Re: Danfoss

You can find all information on these units in the following PDF file:

http://www.danfoss.com/compressors/pdf/datasheets/r134a_12-24v_dc/R134a_12-24V_DC_11-01_Cn46c602.pdf

It's very detailed and useful if you are using these Danfoss compressors.

You are right in that the box essentially contains an inverter. But it uses a differnt technique, than a simple resistor to cover an optional input voltage range from 9.6V to 31.5V. A resistor would trun the excess power into heat and would not be very efficient. With the used technique, the current draw at 24V is exactly half that of a 12V supply.

The compressor is AC, but 3-phase, with a permanent magnet as the rotor. A little bit more efficient than the single phase AC types used in household fridges.

<hr width=100% size=1><A target="_blank" HREF=http://www.taniwani.de>http://www.taniwani.de</A>

 

[colvic]

Re: Danfoss

Hi vyv

From what I've checked with the factory, the actual change from 24v to 12v takes place outside the "black box"; this is the small resistor fitted where the supply enters the back of the fridge. The box itself then uses the 12v to operate the compressor which is still basically a mains one with the addition of a magnetic device that the control box manipulates into thinking it is being supplied with 220vAC and not 12vDC.

The truth is we are being charged something in the region of £350 for the control box!


Phil

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[vyv_cox]

Re: Danfoss

I checked with my information source and he agrees with the posts above - I probably didn't ask him the right question in the first place. However, he tells me that inverter problems on the older Danfoss units were fairly common, whereas on the BD unit they are extremely rare.

Vyv

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