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OT-Fancy domestic refrigerator, Vfd 3ph compressor

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  • OT-Fancy domestic refrigerator, Vfd 3ph compressor

    An expensive looking domestic refrigerator arrived at the junkyard this morning. I ran a power cord out to it and a digital display on the door lit up, but I couldn't here the compressor.
    Pulled a panel off the lower back. A sticker on the sealed unit said 1/3 hp 3ph 230V. I never have seen this before. I opened a large plastic box on the side that had 110V input to a circuit board and 3 wires out to the sealed unit and 2 light wires to a-thermostat? It wasn't running, so I cut the 2 thermostat wires and twisted them together, bypassing the thermostat. No go. Maybe the circuit board was bad so I connected 110 directly to 2 compressor wires and a small ac fan capacitor in series to the third motor wire, bingo! It was running on 110.
    I'm guessing this newer refrigerator had a VFD to have a soft start, lower inrush current and eliminate the mechanical start relay and capacitor. I bet the service call and cost of the VFD board replacement would be outrageous and rarely ordered.
    Anyway this was new to me and maybe interesting to some of you. A refrigereator with a VFD and a 3ph 230V compressor running on 110V single ph, Fancy. I left it to it's fate, darn , but I learned something new.

  • #2
    I have a Frigidaire inverter powered fridge. Same basic setup. The reason I bought it is because it is nearly silent, not to mention being quite energy efficient.
    Southwest Utah

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    • #3
      Silent and efficient- but not very long lived. I hope I'm wrong on that last part. But, well, here's a case of a dead one. I know of at least one service guy that has those hvac motors laying around, defective- apparently that's common. There is going to be a built-in failure rate because they build them right to the edge of cheap.

      Gone are the days of the Coolerator, still running after 50 years. Crammed with tv dinners and ginger ale-
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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      • #4
        My 1994 washing machine has a 3 phase motor and "vfd". Still going strong, at least 10 minutes ago.

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        • #5
          Now you have 12v camper fridges with a 3 phase inverter motor as well. They will even run without a battery just connected to a solar panel. When there is enough voltage/current available, the compressor will run.
          Helder Ferreira
          Setubal, Portugal

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          • #6
            Originally posted by darryl View Post
            Silent and efficient- but not very long lived. I hope I'm wrong on that last part.
            My Samsung inverter-powered fridge/freezer had a 10 year guarantee. We've had it about ten years and just yesterday bought a new replacement of the same type.

            Nothing wrong with the wrong one, we have just replaced it as a matter of course. Donated the old one to a deserving friend.
            Peter - novice home machinist, modern motorcycle enthusiast.

            Denford Viceroy 280 Synchro (11 x 24)
            Herbert 0V adapted to R8 by 'Sir John'.
            Monarch 10EE 1942

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            • #7
              Here by code exhaust fans in non-residential more than a couple hundred cfm need to be variable speed (energy code). The motor is three phase, has the electronics in the end cap, and is fed from single phase. Small remote potentiometer adjustment for speed.

              I might snag one from work to replace the old single phase motor / light dimmer used on my fireplace (only 'cos I can).
              Last edited by lakeside53; 05-30-2020, 11:42 AM.

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              • #8
                I think my 12 year old LG washer is inverter powered. My experience with a lot of this stuff is that it's repairable, but they just don't want to make that economically sensible. I just replaced the defroster in a 13 year old Samsung fridge, but they made me buy the entire evaporator unit to get it! I've replaced the mainboard 3 times now.

                Location: Jersey City NJ USA

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                • #9
                  I THINK that my wife's 2010 Camry has an electronically controlled fan for the AC. t reminds me of a VFD controlled 3 phase design. It has a continuously variable speed range, and when it had a problem (dead rat in the squirrel cage fan) it shut itself off sort of like a VFD does when it's overloaded and too slow to get up to speed.

                  Dan
                  At the end of the project, there is a profound difference between spare parts and left over parts.

                  Location: SF East Bay.

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                  • #10
                    I just bought a new washer today, old one lasted just over 38 years. I hope it outlasts me but I'm not optimistic about it.
                    Location: Saskatoon, Saskatchewan, Canada

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                    • #11
                      Originally posted by darryl View Post
                      Silent and efficient- but not very long lived. . . .
                      I know you've had a lemon, but the Frigidaire has a great warranty and reputation, and my shop mini-split (also inverter powered) has been slaving away for 10 years without issue. The summers are very hot here too (yesterday and the day before were 104-106F at my house).

                      Southwest Utah

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                      • #12
                        Originally posted by the professor View Post
                        I'm guessing this newer refrigerator had a VFD to have a soft start, lower inrush current and eliminate the mechanical start relay and capacitor. I bet the service call and cost of the VFD board replacement would be outrageous and rarely ordered.
                        It's not about increasing the life of the motor, the manufacturers have gotten those small hermetic compressors to be very reliable so the extra expense is not justified there. Variable speed capability is all about energy efficiency. Slowing down the compressor gives a better EER (Energy Efficiency Ratio, how many btu gets moved per watt of electrical energy), so by slowing down the compressor to match the load rather than cycling the system on and off you can see some significant energy savings (10-40%, depending on the system and who you talk to). As a bonus it keeps the system more stable, giving a more consistent temperature than an on-off cycle.

                        https://www.secop.com/solutions/appl...controller-ccd

                        This is all being driven by tighter and tighter energy regulations set by governments.
                        Cayuga, Ontario, Canada

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