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I had 2 of these swing motors on a Norcold fridge in my boat. First one lasted 15 yrs other 20 yrs. It was cheaper to buy a new fridge then replace compressors.

Or more probable is Engel can't find a company willing to make them since their engineers didn't design it.

Originally Posted by engineerdave

I thought this looked cool, haven't seen one in real life yet...
www.turbocor.com

I went to a training seminar on those a couple years ago. Got to play with one that was cut open so we could spin the compressor by hand... Then I never really had to work on one, though I've seen them in operation. They're extremely quiet. You hear a little compressor whine and the refrigerant rushing through the system. They make for very quiet mechanical rooms.

They're definitely expensive, but they're also extremely energy efficient. It's a tough call for a lot of companies between a turbocor compressor and a screw. Screws are cheaper, turbocors are more efficient. If the turbocors were a little cheaper I think we'd see a lot more of them out there. I wish there were more of them out there. They sure are easy to be around while in operation.

They sound expensive.

I thought this looked cool, haven't seen one in real life yet...
www.turbocor.com

Originally Posted by Poodle Head Mikey

The company claims that they last for decades - with some still running since the 1960's.

Where did you get the information that they only last a few months?

PHM
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Bought the norcold . POS.

Nope! I'm wrong - it's not even 7 mph. I forgot the 12 to get down to feets.

Sorry about that. <g>

Why don't solenoid valves do that then? Aren't they pretty much the same thing except out in the open?

Wait a minute: say the piston stroke was just 1" long. That would have the piston covering over 430,000 inches every hour. Which is over 80 MPH. <g>

Are you sure that's the operating speed on 60 cycle power supply?

PHM
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coils

Originally Posted by craig1

If you're powering it from a standard AC power source you don't need any type of controller, it will run at 60 cycles per second, just like the AC frequency.

Originally Posted by Poodle Head Mikey

I wonder what triggers the power on and off the the wound coil?

If you're powering it from a standard AC power source you don't need any type of controller, it will run at 60 cycles per second, just like the AC frequency.

After a little digging, I found that this swing motor compressor has been made by Sawafuji in Japan, who purchased the licensing from its West German inventor in 1956. Apparently, Engel wasn't the only ones using it because Sawafuji also made mobile mini-fridges with the swing motor compressor and sold them in the USA under the name of Norcold.

They use an inverter to control the oscillating frequency to match that of the spring resonance in the motor.

The company claims that they last for decades - with some still running since the 1960's.

Where did you get the information that they only last a few months?

PHM
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Originally Posted by toocoolforschool

They are not popular because they only last a couple of mths.

Originally Posted by GT Jets

Small enough to be powered by a 12VDC or 24VDC power source... Can't even venture a guess, but suspect it's under 2000 BTU's

GT

At 12VDC< 100 Amps it's unreasonable for a constant load, with a peak load under 200 Amps with size 0 cables. So that's puts you at 1200Watts, or with a COP or 3, that's as much as 12,000 BTU's. BUt I think you'll be limited there. I think the small AC units that companies like Webasto make for sleeps babs are in the range of 6000-12000 BTU's.

Originally Posted by motoguy128

All aquarium air pumps since ohhh... 30 years ago when I started the hobby, used simple coils to move a diaphram "piston". I suspect it cycled at 60 Hz. SOme might have used 2 diaphrams, on on each end of the stroke.

The ones they had in these lobster tanks were huge compared to your standard aquarium pump. 3/4" air outlet and capable of about 30 PSI. When I looked them up on the Internet they showed how it worked and it was a Teflon coated floating piston the slid back and forth in a tube. Very cool design. Apparently most of these style pumps are used as septic tank aerators.

Originally Posted by Poodle Head Mikey

Someone just told me that Engel has a patent on the compressor design and doesn't want to allow anyone else to make them. I guess that would explain why they aren't in common use. I wonder what triggers the power on and off the the wound coil?

Probably SCR's (I think that's the term) some sort of solid state device similar to what's in an inverter. More similar I suppose to a Servo drive since it's a PM magnet for the stator. As stated in the mfg website, the stroke lenght and speed are vairable which allows low start-up load and I suppsoe also vairable compression ratio.

Originally Posted by craig1

Wow, I never knew they made those for refrigeration use. There's a company that makes low psi air compressors that work the same way and their reliability is light years ahead of the conventional piston compressors. A store I work for has had them on the air supplies for lobster tanks for 15 years now with no maintenance or failures. All the other stores are using more expensive conventional piston compressors that need to be replaced every 5 years and use almost 5 times more power.


Seems like a no brainer for refrigeration use.

All aquarium air pumps since ohhh... 30 years ago when I started the hobby, used simple coils to move a diaphram "piston". I suspect it cycled at 60 Hz. SOme might have used 2 diaphrams, on on each end of the stroke.

Really, from that standpoint, the design is short sighted. It might as well have 2 cylinders, one at each end and just use a reed valve or similar as a check valve.

They are not popular because they only last a couple of mths.

Someone just told me that Engel has a patent on the compressor design and doesn't want to allow anyone else to make them. I guess that would explain why they aren't in common use. I wonder what triggers the power on and off the the wound coil?

Originally Posted by Poodle Head Mikey

Isn't that a straw-man argument you are making? <g>

The compressors have one moving part. <g>

The "hours on the starter" has nothing to do with this discussion - which was about why the compressors are not commonly used. You suggested that it was due to them operating on a low voltage, such as 12 or 24 and so having low capacity. "Teeny-tiny" was the descriptive phrase. The reliability was never an issue.

PHM
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PHM, I believe you are simply misunderstanding where I was coming from.

Being as the starter on your truck has a duty cycle of like .001%, it draws an incredible amount of amperage (read watts) for an extremely short (comparatively) amount of time.

A refrigeration compressor on the other hand has a duty cycle of say 90% if not 100%, which means it would have to draw very little current (again watts). So using this logic, it would have to have a relativity low HP, or small capacity, this compressor seems to have been developed specifically for portable refrigeration equipment. The company seems to be an automotive generator manufacturer.

Not trying to start a major debate, just wanted to make sure my point was clear.

GT

Isn't that a beer cooler in the upper RH corner?

I'd say that's a low capacity unit, like a sterling cooler.

Isn't that a straw-man argument you are making? <g>

The compressors have one moving part. <g>

The "hours on the starter" has nothing to do with this discussion - which was about why the compressors are not commonly used. You suggested that it was due to them operating on a low voltage, such as 12 or 24 and so having low capacity. "Teeny-tiny" was the descriptive phrase. The reliability was never an issue.

PHM
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Originally Posted by GT Jets

and how many HOURS are on that starter? High torque items like a start only run a few seconds at a time, refrigeration compressors on the other hand, well, the opposite.

Be sure to update us on the max capacity. I does not impress me too much personally, but then again, who am I?

GT