Difference between revisions of "Running your 12 VDC fridge on 120 VAC shore power"
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=Running your Adler-Barbour fridge on shore power= | =Running your Adler-Barbour fridge on shore power= | ||
+ | ====''By John Nixon''==== | ||
{| | {| | ||
|First, a little background and history of the Adler-Barbour compressor. Prior to early 2000, all the compressors were fixed speed, brush commuted motors that had a very nasty current spike when the compressor started, but also were very electrically noisy while they were running. The installation manual for these units made a strong point of using big wire from the battery and the fact that you had to have a battery on the feed circuit to help "absorb" the current feedback of the motor back into the voltage source. Upon starting, the peak starting current was in the neighborhood of 17 amps for a couple of hundred milli-seconds. However, my discussions with the engineering folks back then ( pre-WAECO ) confirmed that with a reasonably "stiff" power supply ( i.e. - AC-to-DC power supply ) there was no reason that the compressor wouldn't be happy without a battery in the feed circuit. Of course, I had already tried it by then and knew that to be the case, but it made me feel better having them agree with me...... I used a 250w 12 volt nominal switching power supply with the output voltage set at about 13 volts, which meant that I had about 19 amps available. I used this from the end of 2002 with no problems on my Stamas 44, and the next owner is still using it. The power supply had a cooling fan that ran all the time, and the fan quit after about 3 years. However, since the run current of the compressor was only about 5 amps, the cooling fan wasn't really necessary anyway, and it wasn't an issue. However, the supplier of that power supply no longer carries or makes that power supply, so to duplicate what I did will require some adaptations ( at least at a reasonable price..... ). | |First, a little background and history of the Adler-Barbour compressor. Prior to early 2000, all the compressors were fixed speed, brush commuted motors that had a very nasty current spike when the compressor started, but also were very electrically noisy while they were running. The installation manual for these units made a strong point of using big wire from the battery and the fact that you had to have a battery on the feed circuit to help "absorb" the current feedback of the motor back into the voltage source. Upon starting, the peak starting current was in the neighborhood of 17 amps for a couple of hundred milli-seconds. However, my discussions with the engineering folks back then ( pre-WAECO ) confirmed that with a reasonably "stiff" power supply ( i.e. - AC-to-DC power supply ) there was no reason that the compressor wouldn't be happy without a battery in the feed circuit. Of course, I had already tried it by then and knew that to be the case, but it made me feel better having them agree with me...... I used a 250w 12 volt nominal switching power supply with the output voltage set at about 13 volts, which meant that I had about 19 amps available. I used this from the end of 2002 with no problems on my Stamas 44, and the next owner is still using it. The power supply had a cooling fan that ran all the time, and the fan quit after about 3 years. However, since the run current of the compressor was only about 5 amps, the cooling fan wasn't really necessary anyway, and it wasn't an issue. However, the supplier of that power supply no longer carries or makes that power supply, so to duplicate what I did will require some adaptations ( at least at a reasonable price..... ). | ||
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When I have the schematic diagram of the power change-over relay scanned into a suitable format, I'll post it here as well. | When I have the schematic diagram of the power change-over relay scanned into a suitable format, I'll post it here as well. | ||
− | |[[image:Fridge -direct AC-DC PS with Relay via John Nixon.jpg| | + | |[[image:Fridge -direct AC-DC PS with Relay via John Nixon.jpg|350 px|AC/DC power supply option]] |