Engel Fridge help
Submitted: Saturday, Dec 02, 2023 at 00:13
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nestor m
Good afternoon, I am trying to repair a Engel Fridge circuit board, in my case the compressor does not turn on, the fuses are good, could someone please tell me if the output voltage to the compressor is reversible or are they simply 12v pulses with a specific frequency?
Reply By: RMD - Saturday, Dec 02, 2023 at 08:29
Saturday, Dec 02, 2023 at 08:29
The voltage should be a sine wave around 20V ac value. It moves the solenoid piston by creating a magnetic pulse through a cylindrical coil to, magnetically drive the piston shaft magnet back and
forth. Frequency 50HZ or close to.
From memory the resistance of the so called MOTOR, which it doesn't have, is approx 2.7 Ohms, does vary between models.
AnswerID:
644828
Reply By: Allan B (Sunshine Coast) - Saturday, Dec 02, 2023 at 16:46
Saturday, Dec 02, 2023 at 16:46
.
Hi Nestor,
The Engel's Sawafuji solenoid motor's drive arrangement has changed over the years.
When supplied from a 12vdc source, the supply is always inverted to a square wave of 14-18 volts and a frequency of about 50 Hz. However, when driven from the mains, the early models applied that directly to a winding of the inverter transformer then on to the motor whereas the later models applied the mains to a separate mains transformer and rectifier circuit whose dc output went to the inverter circuit to produce the 14-18vac feed to the motor coil. So in all cases the voltage applied to the motor coil reverses at 50Hz.
So based on that, you probably could apply 12v 50Hz to the motor coil and successfully drive the motor, although I have never actually tried it. It should do no harm to try it but be sure that you apply the nominal 14-18vdc to the motor only and not allow it to feed into the electronics.
And whatever you do, especially if you are not fully trained in electrics, be bloody careful to avoid electric shock.
p.s. I have no knowledge of why Engel made those design decisions but maybe it was because the motor operates as a *resonant frequency device* and it will be most efficient when driven by an electrical source of its design resonant frequency. The Engel fridges were being marketed into countries using primarily 50 or 60 Hz and the later design could accept those frequencies whilst maintaining 50Hz to the motor. Interestingly, Japan is divided into two zones that have mains frequencies of 50Hz and 60Hz respectively although I don't know if that is of significance to Engel's design choices.
And you may be interested in reading more in an earlier
Forum Thread 146267.
(here).
AnswerID:
644836
Follow Up By: RMD - Tuesday, Dec 05, 2023 at 12:09
Tuesday, Dec 05, 2023 at 12:09
Allan
If needing to, wanting to or having to, run an ENGEL compressor on a18V sine wave source, in your opinion, would it be wiser to supply a half wave rectifed signal to the compressor so there is no negative, below the 0 line aspect of power to the coil and therefore reducing the heat developed in the actuating coil?
FollowupID:
925025
Follow Up By: Allan B (Sunshine Coast) - Tuesday, Dec 05, 2023 at 14:49
Tuesday, Dec 05, 2023 at 14:49
Hi RMD,
I would expect the Engel Sawafuji solenoid motor to run satisfactorily on a 14-18vdc sine supply. The overheating you experienced may have been from a cause other than a sine wave. The early models did pass a sine wave supply to the motor via a transformer.
The heat produced in the motor coil is the result of a number of factors and I would not hope to be able to valuate them or contemplate its relationship to the waveform. It is complex.
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