Rotary inverter driven camping fridge compressor

Submitted: Thursday, Jan 06, 2005 at 17:37
ThreadID: 19118 Views:4896 Replies:6 FollowUps:33
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For those who need a refresher read post 18859

My understanding is as follows:

The compressors used by the particular Manufacturer of portable fridges, were first made by Senlin Electrical Appliance compressor plant in China, which was a joint venture between Mitsubishi and Shanghai Senlin.

I beleive the Mitsubishi compressor Model RR120 is the Senlin model XAZ309.

In standard form the compressor has a nominal capacity of 99watts refrigeration at –23.3 C suction temperature, (a industry standard rating point) running on 240 Vac 50 hertz. This capacity also equates to what the manufacurer stated their compressor does on 50hz.

The compressor has a nominal input (power consumption) of .085 watts.

These compressors used in said fridges are driven by a 12vdc – 240vac inverter, and, the speed of the compressor motor is increased by altering the frequency output of the inverter. The output frequency to the compressor is around 60 hertz.

This speed increase also increases its capacity and this can be calculated easily. The compressor performance then works out to be approx 119 watts of refrigeration. ie 50hz divided 60hz = .83…. & therefore 99 divided by .83 = 119 watts refrigeration. Whilst claiming input watts of 98.4.

For your reference only: I cannot understand why the watts input
have’nt gone higher, to say around 100, but I will give them the benefit of the doubt. The manufacturers data for a the XAZ309 compressor operating on 60hz gives 123watts refrigeration duty & has input watts of 100. Minor but a slight increase on their data.

To arrive at amps on 12v they used the formulae: amps = watts divided by volts ie 98.4 divided by 12vdc = 8.2 amps….so where are the inverter losses I ask?

I re-iterate, they state the following on their web site:
“The following wattage consumption (input), wattage produced (output) and co-efficient factors (co-ef) are derived from each compressor manufacturers specification”. Note the word DERIVED! meaning calculated….but they forgot to include something…eh?

Then we have the other associated in-efficiencies due to the greatly oversized compressor to take into account.
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Reply By: Bonz (Vic) - Thursday, Jan 06, 2005 at 18:26

Thursday, Jan 06, 2005 at 18:26
whattttt??? not again...........
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Follow Up By: Nudenut - Thursday, Jan 06, 2005 at 18:31

Thursday, Jan 06, 2005 at 18:31
Just letting all know that I now have the tech data and I can prove I am right if someone wants to question it!
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Follow Up By: Member - Crazie (VIC) - Thursday, Jan 06, 2005 at 20:12

Thursday, Jan 06, 2005 at 20:12
Hey Bonz
What did he say????
Hahaha

Thanks for the insight Nudenut
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Follow Up By: Bonz (Vic) - Thursday, Jan 06, 2005 at 20:15

Thursday, Jan 06, 2005 at 20:15
he mentioned compressors hahahahah acrtually amongst all the he said / he said stuff I actually learned a bit about refrigeration, and my mate Nudey pointed me in the right direction at it. I was whaaaaatttttt-ing at having to learn more hahahahahahaha.
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Follow Up By: Nudenut - Thursday, Jan 06, 2005 at 21:09

Thursday, Jan 06, 2005 at 21:09
i knew you needed more theory instruction Bonz! hehehe
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Reply By: Rick Blaine - Thursday, Jan 06, 2005 at 20:51

Thursday, Jan 06, 2005 at 20:51
Rotary Inverter... do you mean like we used to have in Sydney to convert 3 phase power to 600VDC to power trams???? Of course later on Mercury arc rectifiers did the job....
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Follow Up By: Nudenut - Thursday, Jan 06, 2005 at 21:07

Thursday, Jan 06, 2005 at 21:07
Trams....what are they pray tell?
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Follow Up By: Bonz (Vic) - Friday, Jan 07, 2005 at 22:47

Friday, Jan 07, 2005 at 22:47
ahh remember the aura that the arc rectifiers threw around themselves, that calming glow that reminded me of Frankensteins laboratory.

Nudie you know what trams are, Melbourne has one or two.
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Follow Up By: Nudenut - Sunday, Jan 09, 2005 at 21:51

Sunday, Jan 09, 2005 at 21:51
melborne......wheres that....south of tas?
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Follow Up By: Bonz (Vic) - Monday, Jan 10, 2005 at 18:04

Monday, Jan 10, 2005 at 18:04
yannow sydney? yer? well Sydney is one of Melbourne's northern suburbs. Trams dont go as far as that tho
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Reply By: Eric Experience. - Thursday, Jan 06, 2005 at 23:09

Thursday, Jan 06, 2005 at 23:09
Nude nut.
My heart missed a beat when I read you opening line, for a moment I thought you have slipped back 40 years to rotary inverters, please put a comma after rotary.
your figure of power consumption is remarkably low,
The pumping efficeincy decreases with speed so the 60/50 htz figure may be a bit ambitous, some shaded pole motors designed in the USA saturate on 50htz but not on 60htz, that may explain the lack of extra power consumtion but I suspect that the data was put out by a sales "engineer", you know the one that has shares in the company. Eric.
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Follow Up By: Nudenut - Friday, Jan 07, 2005 at 08:43

Friday, Jan 07, 2005 at 08:43
Compressor manfacturers XAZ309 Tech. data sheet
At 50 hz Input watts 85, Refrigeration capacity 99
At 60 hz input watts 100, Refrigeration capacity 123

I believe the input watts for the above to be realistic. All compressor refrigeration manufacturers produce tech data which usually give performnace data for both 50 and 60 hz. If they dont give the actual figures they tell you to multiply the figure shown on 60hz by .83 to arrive at 50hz performance.

From the said Fridge manufacturers web site they claim 98.4 input watts for the mitsi RR120 (above compressor) running at 60 hz giving 119 watts of refrigeration capacity….is it right? I dunno sounds a little low but let us accept at face value. The point is, the input watts claimed by them are still similar to the compressor manufacturers 60hz data, and they didn’t use an inverter!

So where are the losses of the inverter in data on the web site? These things, 12vdc - 240vac inverters, are typically around 85% efficient. Add 15% to the calculated 8.2 and we get > 9amps?

I say again, the 8.2 amps consumed by the compressor has been calculated (derived) by the Fridge manufacturer using standard electrical formulae….But they mislead us, as the figure shown does not include the losses of an inverter.
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Follow Up By: Eric Experience. - Friday, Jan 07, 2005 at 22:18

Friday, Jan 07, 2005 at 22:18
Nudenut.
I am with you 100%, the inverter would have to be able to take the starting power of the compressor, usualy x5, so 500watt peak unit running at 100watt would be struggling to be 85%. So I think about 10 amps would be my estimate. Do they happen to mention the recomended in line fuse rating? I suspect it would be 50 amps. Eric.
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Follow Up By: Wok - Saturday, Jan 08, 2005 at 07:18

Saturday, Jan 08, 2005 at 07:18
Hello Eric, Cutey,

Are you presenting a case for linear power supply [ at least for fridges] rather then switchmode?

If the efficiency aspect of the two systems is ignored, which method would you favour & why?

cheers
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Follow Up By: Nudenut - Sunday, Jan 09, 2005 at 22:00

Sunday, Jan 09, 2005 at 22:00
i am presenting a case for against ...inverter driven 12vdc-240vac compressor fridges.....

if someone can give me alternative data....Manufacturers...i will check it all out.

If one ignore the current draw.....
thats a hard one Wok
i'd stay with the my trailbaza copy.

but then again the Engel i got for nothing is good....and then the there's always the waeco?mmmmmmmmmmmm?
power or current draw is a concern so i'd stay with the 12v compressors....after all refrigeration research are also using them......????? why?...why not stay with the 240 v comp if its effic.....?
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Follow Up By: Wok - Monday, Jan 10, 2005 at 06:37

Monday, Jan 10, 2005 at 06:37
Nudenut,

I was considering fitting a 240>13.8V supply into my Trailblaza.[ I think i have posed the question before about putting a switchmode in front of another modified sinewave.] It appears Eric & you were discussing DC>ac>240 compressor...my mistake, sorry.
I favour a linear supply [probably because I am familiar with them]...too old to change.

cheers
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Follow Up By: Nudenut - Monday, Jan 10, 2005 at 08:01

Monday, Jan 10, 2005 at 08:01
didnt your trailblaza come with a 240vac -12vdc power supply?
I thought that was standard on them?
Mine is just a standard 240v 150va tranny to ...buggered if i know now hahaha with a rectifier and a couple of capacitors. Not worried consumption on 240 supply so tranny is probably a tad oversized but as it was obtained at the right price..... nothing.... and it works..its right for me
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Follow Up By: Wok - Monday, Jan 10, 2005 at 09:30

Monday, Jan 10, 2005 at 09:30
Nudenut,

Nah...didn't get any fancy add-ons [just a tight-wad!]
Got a toroid...somewhere...do it one of these days....

Do you know of a circuit for cleaning up dirty mains? My plan is to run a 3 stage charger to simultaneously charge my battery & run the fridge. I have tested the setup on town power but reluctant to run the charger [sw mode] off dirty power. If I could do this then I wouldn't need a ps in the fridge.

cheers
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Follow Up By: Mainey... - Sunday, Jan 16, 2005 at 20:03

Sunday, Jan 16, 2005 at 20:03
"Nudenut posted this followup, i am presenting a case for against ...inverter driven 12vdc-240vac compressor fridge..If one ignore the current draw...thats a hard one Wok, i'd stay with the my trailbaza copy, but then again the Engel i got for nothing is good....and then the there's always the waeco? power or current draw is a concern so i'd stay with the 12v compressors.... after all refrigeration research are also using them? why?... why not stay with the 240 v comp if its effic?"

NN, simply because Refridgeration Research actually import the Danfoss powered fridges, they do have thicker insulation than Waeco and are considerably less expensive also, what other questions do you want answered about them?

As to the inverter driven 240v Mitsubishi compressor range of fridges they range from small portables up to the full size walk-in freezers as used on large commercial fishing boats, due to their efficiency, but you already know that.
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Follow Up By: Nudenut - Monday, Jan 17, 2005 at 08:26

Monday, Jan 17, 2005 at 08:26
Ok so we now know that the 12 v fridges are Brand named eh?

And yes I understand they do do the larger stuff for for the boats etc etc but they are not our so-called run of the mill "camping fridges"

I still ask the same question but in a different way...if theirs is so good why import fridges using 12vdc brushless driven compressors then?
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Follow Up By: Mainey... - Monday, Jan 17, 2005 at 09:37

Monday, Jan 17, 2005 at 09:37
FollowUp 9 of 9 posted 17 Jan 2005 at 07:26
Nudenut posted this followup "Ok so we now know that the 12 v fridges are Brand named eh”

NN, Yes, well if you did read the website you would!
http://www.refrigerationresearch.com.au/DR%20portables.htm
NN, It is simply a business decision to have two different price point fridges, the imported Waeco look-alike fridge has much thicker insulation and with the famous Danfoss BD35 compressor, as is used in Waeco and maybe your fridge, it is one of, if not the least expensive fridges in the same quality arena as Waeco and similar fridges, and as you can read on the website they come in various sizes from only $762 with a warranty and no scratches, LoL.

(Quote) and yes I understand they do do the larger stuff for for the boats etc etc but they are not our so-called run of the mill "camping fridges" I still ask the same question but in a different way...if theirs is so good why import fridges using 12vdc brushless driven compressors then”(end quote)

As to your question about the ‘Boat fridges’ yes, they are a totally different product, (to the Danfoss powered fridge) as they do in fact use the same Mitsubishi rotary compressor as the smaller stainless steel “Camping fridge” range due to their inherent capacity to quickly and efficiently cool the product put into the fridge cabinet, as you would also be aware these fridges are cooling the product from all four sides, not just one as in the Waeco and Engel etc, and the cooling 'plate' area is at least three to four times larger, enabling quicker and more efficient refrigeration of the product inside.
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Reply By: Nudenut - Monday, Jan 10, 2005 at 11:01

Monday, Jan 10, 2005 at 11:01
cant help you there Wok
but it'l be a big box? and some extra 8-12kg to lug around wont it?
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Follow Up By: Wok - Tuesday, Jan 11, 2005 at 07:04

Tuesday, Jan 11, 2005 at 07:04
Thanks Nudenut, I checked out ferro-resonant line conditioners , just too bulky.

I will put this project on the white board with the others!

Thanks
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Reply By: Mainey... - Tuesday, Jan 11, 2005 at 00:05

Tuesday, Jan 11, 2005 at 00:05
Nudenut,

I have been watching your thread and expecting to see the relevant information you were given by Reefer when you phoned last week..... you have not post it

Can I ask you . . . Why not ? ? ?
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Follow Up By: Nudenut - Tuesday, Jan 11, 2005 at 08:14

Tuesday, Jan 11, 2005 at 08:14
what revelant information did they supply me with? They would not, or could not?, provide me with any tech data of comp or certified lab tests of fridges. I still dont understand why the second person i spoke to became rather sharp when questioned about claims made on the web site...wonder why? eh?

Mitsubishi supplied me with the tech data sheet....so I do not need their info anyhow...Do You dispute the figures above for said mitsubishi compressor?

We also now know why you push their barrow so hard! where were you when I rang..or better still which representative of the company were you ....the 1st or 2nd one I spoke to, who gave conflicting information to the other?

Now that I know you do have access to the following info, Email me full page copies of tech data you have on said compressor and specification and tech data on inverter drive.......I can check the performance against my figures! If any shortcomings are revealed in my calcs in your favour I will resubmit...and humbly apologise on EO

what more do you want....admit defeat without adequate data from Mainey...how about it Mainey...give me the info to prove me wrong..its for your benefit? right?...might even have to appologise personally to you!

my email is wherethefugawi@hotmaildotcom
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Follow Up By: Nudenut - Tuesday, Jan 11, 2005 at 12:59

Tuesday, Jan 11, 2005 at 12:59
further more....What Irrited Me Most was the so called "Engineers" (the second person) ( not you I hope Mainey) remarks....."the Danfoss is not a dc motor...have you ever heard of a brushless DC motor" He then went onto say "so how do they get it to run on 12vdc"

At this point I guessed and made a reasonable dedcution that "Engineer" couldnt engineer a peeesup at the local brewry.......

are you saying that Danfoss are lying????no answer given!

quote from the Danfoss tech data...
"The BD compressors are fitted with a brushless direct current motor which is electronically commutated by an electronic unit."

Would you like to answer for the Engineer Mainey?

Geez Mainey... note the words..... Brushless Direct Current Motor

http://www.advancedbuildings.org/main_t_motor_prog_brushless.htm
or is this a conspiracy?

These things have been around for yonks....well maybe a bit less but a qualified refrigeration engineer would have or should have known this!!!!

How say you Mainey
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Follow Up By: Nudenut - Wednesday, Jan 12, 2005 at 18:44

Wednesday, Jan 12, 2005 at 18:44
Mainey...why dont you just answer the above first...you like my kids...answer a bloody question with one?...why dont you just answer with revelant answers!

Incidently, I did not hang up despondently on anyone...and I hope your not infering the conversation was ended rudely by me?

Once I recieve answers to the above 3 questions I wil answer you reply below...dont expect to keep asking me questions , getting replies and then trying to vindicate yourself by being elusive to the questions posed upon you!

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Follow Up By: Mainey... - Saturday, Jan 15, 2005 at 12:52

Saturday, Jan 15, 2005 at 12:52
Nudenut, I will not attempt to reply your 'made up' inuendo statements that you yourself can't prove, because you and I both know they were never said, it is a case of you were given factual evidence that proved your case was wrong, by that I state incorrect, and I am referring to your 'original' post, not one of your throw away lines or red herring statements you have started to use to avoid your original statement you made, relevant to the information on the website, that you do now know to be correct, but you will not admit it to save face.

That is the ONLY reason why you did not state you had contacted Reefer
it was an attempt by you to HIDE your own mistake.. untill I mentioned it.

By the way the link to the "brushless dc motor" you have posted is not of a Danfoss motor as you are indicating.... is it, just another red herring thrown in to confuse those who are interested in some truth.
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Follow Up By: Nudenut - Saturday, Jan 15, 2005 at 18:17

Saturday, Jan 15, 2005 at 18:17
are you saying Danfoss lie?
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Follow Up By: Nudenut - Sunday, Jan 16, 2005 at 12:23

Sunday, Jan 16, 2005 at 12:23
I wonder who said or made those remarks Mainey...was it you?

If not how do you know what was or was not said?

Geez I wish I could say "would you like to here the recording?" but that wouldnt be legal....would it?

No its not a link to the Danfoss DC motor but a link to show you that Danfoss are not the only ones who manufacture DC Brushless Motors.

Read their (danfoss) specs on the BD compressor

And i again ask.....Are You Saying Danfoss Lie?

yes or no! Mainey.....or will you spurt out more tripe!
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Follow Up By: Mainey... - Sunday, Jan 16, 2005 at 19:01

Sunday, Jan 16, 2005 at 19:01
NN, Now you are insinuating you have a recording of the Reefer call....
it is legal to tape phone calls, IF, you advise the other person you want to tape the call, and the other person agrees to the call being taped, you did not ask for the call to be taped ...did you? no you didn't!

Please play your alleged tape and tell us all how long you were on the phone call to Reefer.

NN you forgot to mention you phoned Reefer because you were shown why your theory was wrong, that is the only reason you did NOT mention you had phoned Reefer, because in fact the phone call did prove to you that you were not correct, so you did not mention it!

As to brushless motors they were not the reason for the phone call, because your gripe was not wether a Danfoss is or is not a brushless motor, but with electrical power consumption and technical inverter questions relevant to Mitsubishi rotary compressors.

NN stop digging a hole for yourself, produce the recording or admit the truth.
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Follow Up By: Nudenut - Monday, Jan 17, 2005 at 08:20

Monday, Jan 17, 2005 at 08:20
I will say again Mainey...They have not provided me with any such info except for verbal claims of how good their system is......where is their proof...? so what have they proven eh?

And again I repeat myself.....The so-called engineer I spoke to claimed Danfoss compressor is not a brushless motor by stating "theirs is not a 12vdc compressor, have you ever seen a DC motor with out brushes?"

Now for the last time I must ask you to answer this question that you keep avioding to ask:
Are Danfoss lying when they say the BD uses a 12vdc brushless motor?

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Follow Up By: Mainey... - Monday, Jan 17, 2005 at 09:58

Monday, Jan 17, 2005 at 09:58
(Quote)Are Danfoss lying when they say the BD uses a 12vdc brushless motor(end quote)
As to your implied statement an engineer said that, you can't prove it and neither can I disprove it, well not without your implied tape of the conversation LoL, so why argue about it?
NO.... are you happy now, I hope so.

As to what you were told, that is a different question, you did not mention on the forum you had in fact contacted Reefer, simply because you were informed why your argument was in fact wrong...
but you can't disprove that either, so why should I waste electrons quarrelling with you about it!
Well you do have the tape of the conversation, don't you?

Enjoy your day,
as there is no value taking this any further while you are in denial!
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Follow Up By: Nudenut - Monday, Jan 17, 2005 at 10:52

Monday, Jan 17, 2005 at 10:52
i have never said I had a recording....you have made a stupid assumption.....and it isnt illegal...

Mainey, we know you are involved with them somehow.....

If I am wrong why dont you send or get me the details and tech data of the compressor, i have asked for this before....why dont you supply the test results...????? the reason you cant get it is:..........the figures on their web site are "derived"

The engineer did make that statement....if you knew I rang how is it you do not know what was said...you seem to know everything else that was! or wasnt?...so now you admit that Danfoss do use a brushless DC motor?

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Follow Up By: Mainey... - Monday, Jan 17, 2005 at 23:11

Monday, Jan 17, 2005 at 23:11
Nudenut,
please stop wasting forum space, you "prove" the numbers are NOT correct, if you want the credit then you do the work, you are claiming to be a fully qualified fridge mechanic, with various certificates certifying your competency on your office wall, aren’t you?

Nn, this is getting childish, “I said, he said” and various statements you can’t appear to prove by yourself.

Simply stated, you were informed of the facts when you phoned and you did not post them here on the forum, you did not even mention you phoned because the information given to you would only show you are incorrect.

(quote)Geez I wish I could say "would you like to here the recording?" but that wouldnt be legal....would it(end quote) your words, not mine, talk about confusion, now I think I see why you don't comprehend.

Get over it and take a holiday... as I have!
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Follow Up By: Nudenut - Tuesday, Jan 18, 2005 at 08:07

Tuesday, Jan 18, 2005 at 08:07
I was informed of what facts...spell them out here!
The so called engineer (was it you) was spitting bull*^%$
No facts were given ...just fabricated figures..lies

If I am wrong....you Prove It!.....your full of it!!!!!!!!!
cya and enjoy your holiday hahaha



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Follow Up By: Mainey... - Tuesday, Jan 18, 2005 at 10:28

Tuesday, Jan 18, 2005 at 10:28
(Quote)The so called engineer (was it you) was spitting bull*^%$
No facts were given, just fabricated figures, lies(end quote)

Nudenut, IF that was even partly true, to some itsy teeny weeny very small degree, you would have posted immediately here on the forum espousing to everyone that you in fact did phone Reefer, and you would have attempted, note the word selection, attempted to disprove the facts you were given.

But no, you were given facts you could not disprove and you were shown why your own pet theory is wrong.

That, is the only reason you did not declare on the forum you did make that phone call, because you attempted to hide the real truth and when you were asked ‘why’ you did not get on the forum and post you had phoned Reefer, if you had believed you had been given incorrect information you would have stated that here with all the verbal vitriol you are capable of you don't answer, do you?

No, I am fed up with you attempting to hide the truth and making out someone other than you is incorrect.

You have been shown to be very Machiavellian by not posting you were given the relevant information you asked for, and when you are asked to state what technical qualifications you actually have on your office wall, you don’t, you hide behind your computer screen.

As I believe you 'should' be very capable of ascertaining the truth (again) without my assistance, because you don’t believe me anyway, do you? I will say good bye and yes, thanks I will enjoy my holidays.
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Follow Up By: Nudenut - Tuesday, Jan 18, 2005 at 15:40

Tuesday, Jan 18, 2005 at 15:40
I re-iterate..i was not given any facts....just verbal crap

I have exposed the truth not hidden it! I dont e see the need to say I rang anyone...i rang lots of persons b4 I managed to get the info on the compressors...not just that stupid engineer up mt barker way!

Your fed up? Sue me!!!

Herein and some where on this forum, I have detailed my qualifications
Its up to who ever if they want to believe them and my abilities. And I guess you dont eh? But your not what you make us to believe either....

And no I and many others dont believe you....

Hope you have good weather and take your time wont you ...we wont miss you......
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Reply By: Mainey... - Wednesday, Jan 12, 2005 at 12:37

Wednesday, Jan 12, 2005 at 12:37
Nudenut,

Question; - Why did you not mention on the forum;

The fact you phoned Reefer Refrigeration to get technical answers,
and then post those answers given to you here on your own thread ? ?

Answer;

Simply because you were given factual, direct answers to the questions you asked,
and those answers proved your own thoughts to be wrong.

That is the sole reason you did not mention you phoned them,
because you were shown the error of your wrong idea's when it was technically explained to you, and it was you who hung up despondently.

Now you attempt to diffuse your phone call with more verbal innuendo !!
AnswerID: 92623

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