Danfoss Compressor Speed Controller

Discussion in 'The Projects Forum' started by RVRepairer, Dec 28, 2015.

  1. RVRepairer

    Thread Starter New Member

    Dec 28, 2015
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    I have a refrigeration unit powered by a Danfoss compressor unit.
    The compressor has the ability to operate at variable speeds via a variance of resistance in the thermostat circuit eg. at 1523 ohms .... 3500 rpm whereas at 0 ohms ...... 2000 rpm.
    After market add-on's by third party manufactures have allowed consumers to manually change the resister settings to match optimized running conditions or have produced a timing circuit as shown below to 'automate' the change of speed dependent of running time.

    The question I ask is what circuits would be appropriate for this operation based on variable times and speed change (resistance dependent) ?

    Any thoughts would be appreciated.

    Cheers... Bjorn

    Compressor Speed Adjust Circuit.png
     
  2. #12

    Expert

    Nov 30, 2010
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    What operation? Manually changing the settings? Duplicate the activities described on your chart? Respond to the koala vs kangaroo population?
     
  3. debe

    Well-Known Member

    Sep 21, 2010
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    DANFOSS CONTROLER.1.JPG WAECO_CF_40_VER_A_1.jpg WAECO_CF_40_VER_A_2.jpg Heres the circuit ive drawn out of a Waeco fridge that uses a Danfoss BD35F compressor. U1 is an 8bitprocessor that controls Q1 & Q2 to give varying compressor speeds at diferent temperatures. Hope this is some help..
     
  4. RVRepairer

    Thread Starter New Member

    Dec 28, 2015
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    #12 .....a circuit suitable to duplicating chart activity. Thanks for a swift response.

    debe.....thanks for circuits. The compressor is the Danfoss BD50F ...controller 101N0210.
     
  5. RVRepairer

    Thread Starter New Member

    Dec 28, 2015
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  6. debe

    Well-Known Member

    Sep 21, 2010
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    My thaughts on this are that the beter way is speed controlled by the temperature as in the Waeco system. Where if the temperature rises too high the processor then gives a higher compressor speed. then reduces it when the temperature is nearer where it should be. That being said im not into processor design. My approach in portable 12V DC refrigeration is simple is best. I do have 2 Waeco fridges, but I also converted a Evakool fiberglass esky which has far beter insulation than the Waecos. I just used a $15 electronic thermostat from Ebay. My compressor speed has a switch for economy 2000rpm & power 3000rpm. It spends most of its time on the economy seting, The power setting is only used if ive loaded the fridge up & want it cooled quickly, then it lives on economy. This is my converted Esky. CIRCUIT & REG.JPG FRIDGE.3.JPG TEMP.1.JPG ECONOMY--POWER Swich.JPG
     
  7. RVRepairer

    Thread Starter New Member

    Dec 28, 2015
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    Thanks Daryl.....I reckon the chiller box will be getting a serious workout in those SA temperatures..

    As far your comment re a circuit which was temperature/ speed related would be ideal...I totally agree. However I am still curious on how Merlin actuates the speed change using a formula based on run time duration etc. The search goes on.
    All the best for 2016......Cheers, Bjorn
     
  8. debe

    Well-Known Member

    Sep 21, 2010
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    It would be interesting to know how they arrive at that formula & I assume its done with a microprocessor. I checked out the link you posted but they don't show the other side of the circuit board. All the best to you in 2016 as well. Yes its been a bit warm here. Daryl.
     
  9. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    The thermostat circuit eg. at 1523 ohms .... 3500 rpm whereas at 0 ohms ...... 2000 rpm.
    Which type of motor is it?
    how directly the speed is changing.?

    The micro used datasheet it of samsung
     
  10. debe

    Well-Known Member

    Sep 21, 2010
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    Its a Danfoss 12v/24v variable speed compressor for portable refrigerators. The motor is 3 phase & is driven by a variable frequency.in the controller. BD35F.COMPRESSOR.JPG DANFOSS CONTROLER.3.JPG
     
    RRITESH KAKKAR likes this.
  11. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    I have seen in mechanical lab any time doesn't know how te gas circulation work..
     
  12. debe

    Well-Known Member

    Sep 21, 2010
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    Sugest you Google Refrigeration Cycle for further information on the basics.
     
  13. surfer21

    New Member

    Mar 16, 2016
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    In our region has been several problem by the controller SECOP 101N0212. How could I test it the unit's problem? The LED flash No. is not valid. Somebody knows the circuit? Without the controller could not start the compressor's BD35F. How is possible start the compressor without the control unit?
     
  14. debe

    Well-Known Member

    Sep 21, 2010
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    The Compressor canot be run without the controller, as it generates a 3phase voltage from 12/24V DC. Why is the LED flash flash code number not valid? What is your problems with these controlers?
     
  15. surfer21

    New Member

    Mar 16, 2016
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    The compressor don't start to working just for 10 seconds. The LED twice flash mean: "the fan loads he electonic unit with more than 1 A peak.." But if no any connection to the fan - the flash No. is the same. It is inpossible....The fan current consumption is just 250 mA on 12 V DC....
     
  16. debe

    Well-Known Member

    Sep 21, 2010
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    What make & model fridge? I presume you removed the fan connection from F on the controller? If theres no conection on F & there is still a fault code then I suspect the controller is faulty. I have had a faulty fan draw too mutch current on a Waeco fridge.
     
  17. surfer21

    New Member

    Mar 16, 2016
    3
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    Thank you Debe. The fridge is VITRIFIGO 42 L - Italian. It's on a yacht as fridge. First of all the evaperator was faulty. It's changed for a new one. The cooling circuit is ready - the gas filling is R134a- 50 g. We would able to find the controller faulty but no any drawing for the panel. The inverter technic generally using in the air condition units now. This is key point to controling the RPM of the compressors.
     
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