Danfoss AEO controller

[Richard Kollmann]

Originally Posted by OzePete

Richard, I doubt you understand what 'soft start is. It has nothing to do with 'hard starters you quote, they relate to single phase AC motors!

Oh, and when are you going to acknowledge that Secop Motor driver modules are now SOFT START, and have been for nearly two years! You know, the type of motor driver module that you have been bagging just because I have been presenting them as a far better option than the old DOL modules, but perhaps Secop is wrong too!

So who is making the "asinine statements about things that you don't seem to understand". Read your past posts bagging 'soft start modules for a clue, Richard.

Cheers OzePete

I know that my non Danfoss modules for the last four years have a slow hard start feature. But this feature on a well designed and properly installed unit is just a temporary band aid for mistakes made. From what we know about your system it is easy to understand why you need a soft start device.

[OzePete]

Originally Posted by Richard Kollmann

I know that my non Danfoss modules for the last four years have a slow hard start feature. But this feature on a well designed and properly installed unit is just a temporary band aid for mistakes made. From what we know about your system it is easy to understand why you need a soft start device.

Richard we are discussing 'SOFT START! This is where the Motor Driver Module ramps up the compressor speed slowly and not just going from stopped to maximum speed virtually instantly. HARD starters are used on single phase AC motors that have difficulty starting. They usually involve a start capacitor and can NOT be used on these little 3 Phase AC motors.

Check this video for info on 'soft start' . Soft Start compressor Motor Drive Modules | Ozefridge

Secondly Richard you know nothing about our systems yet again you make your typical bellow the belt assumptions and incorrect as usual. But yes we use soft start modules because they don't have the high failure rates. Simple! Failures due to the massive start up power surge that the DOL Modules you advocate have!
Get with the advancement of technology, we have, others have, Secop / Danfoss have, or are we all wrong and only Richard has got it right? I doubt that!

Apparently you have been out of the industry for some time Richard? Things have moved on. Don't be a closed mind thinking you know it all because no one does and you obviously don't. There are many industry folk like myself who are always willing to listen and share information.
We and readers of this forum would be far better served if we do that rather than one of us assuming some sort of self appointed superiority and attacking another's product to avoid the issue being discussed!

BTW Richard, I have never printed or uttered a derogatory word about your products, books etc.

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[john61ct]

Amen to that, anyone sniping and bickering like that just loses credibility afaic

[Richard Kollmann]

Originally Posted by john61ct

Amen to that, anyone sniping and bickering like that just loses credibility afaic

John61, I agree with you it is more than a poor business plan.

[john61ct]

I meant both of you of course.

[OzePete]

Originally Posted by john61ct

I meant both of you of course.

Really! As I quoted in my last post "BTW Richard, I have never printed or uttered a derogatory word about your products, books etc"

I would appreciate the same courtesy as it has become common practice for my company or products to be demeaned by Richard and quite frankly it is a very low tactic.

Again I would welcome any factual debate on refrigeration issues but only if the thread stays on topic and avoids slagging off ones products, as that petty nonsense serves no purpose.

Cheers OzePete

[john61ct]

It is my practice to

focus on the topic's facts and opinions not address the people

ignore contentious unpleasant personalities as much as possible

simply state what I see as true

when I see statements I disagree with, correct them just enough to prevent others from being misled

but as diplomatically as practical, trying to avoid escalating any emotional conflict

and when needed for tgat last goal, let things lie for a while, returning with calm objective consistency later on to make my point when the defensive opposition won't take it as a personal confrontation

I am not here telling you Pete or anyone else how to conduct yourself

just outlining what **I personally** consider "best practices" in dealing with difficult people and

maintaining my credibity in areas where I know more than I do about refrigeration.

I find it very interesting that when Pete and Richard are going at it hammer and tongs over an issue that must have a clear objective answer, the other professional topic experts usually steer clear, don't weigh in to clarify things for us noobs.

I keep such ambiguous issues well noted in my growing knowledge base, and hope to eventually find out who's right. Most likely IMO I will find Pete was some of the time and Richard was as well other times.

But I strongly believe such questions would be more quickly settled if both of you were able to communicate in a less confrontational way, maybe Socratic questioning?

so the other gurus weren't put in the position of "choosing sides" when helping us to get where we all as a community are trying to go, arriving at greater understanding.

[senormechanico]

John,
Isn't that what PM'ing is for?

[skipmac]

My Frigoboat system uses a BD50 compressor and whatever controller module that came with the system when purchased several years ago. Not on the boat so can't get the module part number but my understanding is it runs the compressor at max speed and just switches on and off controlled by the thermostat.

When I purchased the system I also purchased an add on board, the Merlin I smart speed controller that (again based on my understanding) added a "soft start" feature IE started the compressor at a slower speed then ramped up to full speed AND monitored duty cycle vs compressor speed and adjusted the two (lower speed and higher duty cycle) until the lowest power usage was obtained.

Long story short, I managed to kill the Merlin by getting it wet so running with just the basic controller. Without running a test it seems to be using a lot more amp hours and the compressor definitely getting hotter so want to return to a speed control.

Finally to the question.

I can buy another Merlin but if I understand correctly the new AEO controller has the speed control function built in. Is it the same kind of speed control as the Merlin or is the AEO different or better? Does the Merlin II (the latest version) offer any enhancements or benefits that I wouldn't get from the AEC?

If the AEO does the same thing or does it better than the Merlin II its only a little more and I'll buy the AEO instead of the Merlin add on board and keep the old as a spare.

[a64pilot]

Skip, first do you have hold over plates or a thin plate evaporator? Do you have a restricted orifice or a TXV?
Reducing compressor speed is simply a matter of changing resistance in the C and T terminals, the thermostat if you will, that is easily and cheaply done.
Just from reading and playing I’ve come to the conclusion that I’d you have cold plates and a TXV valve, you may not want or need variable speed control.
My gut is that may be the domain for a restricted orifice, especially if it’s a thin plate evaporator.
If it were me and I had a system like that, I think I would want an AEO trusting that maybe Secop knows what they are doing.

I’m nearly certain that from my reading that if I had an AEO on my system it would be quickly running at full RPM, I think it does that if the box doesn’t hit set point in 48 min? My cycle times are far longer than that as I assume most cold plates systems would be.
Then based on what John said about a TXV being a cruise control, I have observed myself my amp draw being widely variable based on the evaporator temp.

I’m looking forward to what the manufacturers and service techs have to say

[skipmac]

Originally Posted by a64pilot

Skip, first do you have hold over plates or a thin plate evaporator? Do you have a restricted orifice or a TXV?
Reducing compressor speed is simply a matter of changing resistance in the C and T terminals, the thermostat if you will, that is easily and cheaply done.
Just from reading and playing I’ve come to the conclusion that I’d you have cold plates and a TXV valve, you may not want or need variable speed control.
My gut is that may be the domain for a restricted orifice, especially if it’s a thin plate evaporator.
If it were me and I had a system like that, I think I would want an AEO trusting that maybe Secop knows what they are doing.

I’m nearly certain that from my reading that if I had an AEO on my system it would be quickly running at full RPM, I think it does that if the box doesn’t hit set point in 48 min? My cycle times are far longer than that as I assume most cold plates systems would be.
Then based on what John said about a TXV being a cruise control, I have observed myself my amp draw being widely variable based on the evaporator temp.

I’m looking forward to what the manufacturers and service techs have to say

Hello,

The Frigoboat system I have is an Al, thin plate evaporator with a cap tube.

Am aware that the speed can be regulated by resistance between C&T terminals but that sets the speed to a fixed value. The Merlin speed control board connects to the C and T terminals and varies the speed according to onboard algorithms and operating conditions. It monitors system performance and based on previous duty cycles adjusts the speed to a minimum and a longer run time but will also increase compressor speed under high load conditions.

https://www.coastalclimatecontrol.co...uctions-v3.pdf

Is this what the AEO controller does?

[a64pilot]

Originally Posted by skipmac

Hello,



The Frigoboat system I have is an Al, thin plate evaporator with a cap tube.



Am aware that the speed can be regulated by resistance between C&T terminals but that sets the speed to a fixed value. The Merlin speed control board connects to the C and T terminals and varies the speed according to onboard algorithms and operating conditions. It monitors system performance and based on previous duty cycles adjusts the speed to a minimum and a longer run time but will also increase compressor speed under high load conditions.



https://www.coastalclimatecontrol.co...uctions-v3.pdf



Is this what the AEO controller does?

I didn’t look at the link, but yes.
You can find the operating principle of the AEO controller, I did, Ill try to find it again, it wasn’t easy to find and I didn’t bookmark any of this.
Do you know what the resistor is in your thermostat like now? It’s easy to measure of course, just may not be easy to get to.

[a64pilot]

This may help
https://assets.danfoss.com/documents...6586436896.pdf

Biggest advantage I see is that it will vary speed compressor to make cycle on times be 30 min, cycle off times will be a function of insulation, how often you open the box etc. however it should keep the compressor from short cycling which if you look at Rich’s graph of a thin plate restricted orifice system, it’s obviously excessively short cycling.
Of course a cold plate by having so much thermal mass and especially if it phase changes, is not going to short cycle, and will likely have an on time so long that the AEO will always end up in high speed, making it less effective, if effective at all.

On edit, it’s my belief that your system is what the AEO is made for, mine is not.

[skipmac]

Originally Posted by a64pilot

I didn’t look at the link, but yes.
You can find the operating principle of the AEO controller, I did, Ill try to find it again, it wasn’t easy to find and I didn’t bookmark any of this.
Do you know what the resistor is in your thermostat like now? It’s easy to measure of course, just may not be easy to get to.

Well at the moment I am 1000 miles away from my boat so measuring the resistance would not be easy.

Not sure how the Merlin controls the speed. It's just a small PC board with 3-4 smallish chips (no large surface mount ICs), a few caps, diodes and such. Since my (long ago) electronics mainly focused on digital logic I don't know if a board like that can produce a variable resistance or if it controls the compressor speed some other way.

Installation instructions do caution you to remove any resistors installed between C & T if any before using the Merlin to insure proper operation.

[a64pilot]

I’d bet it’s two speed, either no resistance or adds one resistor in line via a relay or whatever is used in the digital world.

Way I understand it and from watching my amp meter, a TXV sort of does mechanically what an AEO does electronically, that is vary the load on the compressor.
Likely of course varying RPM is more efficient than leaving the compressor in high RPM and varying load by changing orifice size.

However I could see how a TXV may confuse an AEO controller, cause the AEO program can’t know what the TXV is doing, is has to assume a fixed orifice.
Why I think an AEO may not work well on either a cold plate, or anything with a TXV.

My theory anyway.

I’m also under the impression that if you have a resistor in line with an AEO module, the resistor puts it into a fixed speed mode, meaning of course then it’s not AEO.