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vspiteri
20-01-2002, 08:44 PM
How can a ref technician note that the mechanical rotation of the compressor is in the right direction with a dual position oil pump and only one sight glass at the bottom of the crank case ?

frank
22-01-2002, 10:48 PM
Any ref eng worth his salt wil know that by using his gauges and amp probe. If the comp is running in reverse direction it will not be pumping the fridge gas and will show up instantly.That is to say on a comp subject to critical rotation such as a scroll. If it is a recip then it doesn't reallly matter about rotation.
Can't really say anymore!:eek:

Abe
23-01-2002, 12:18 AM
now now Frank,

we not all proffessional refrigeration engineers like you or worth our salt in the fridge biz, I am as guilty as anything for asking daft questions, but one thing I must say, members have bent over backwards to help with advice when I have needed it.

I can safely say now that Im a better fridge mechanic now then I was before I started posting on these forums

So, do I stop posting questions now in fear of being lambasted as a mediocre dim wit fridge mechanic by fellow members.

I hope not, look we even entertain the ridiculous sentiments of Mags who goes on about fridges feeling "unfullfilled" I have yet to detect a note of exasperation ........yet, in fact I think secretly members are loving every minute of it!!!

I dont know, these are my views, others may see things differently

Have a good day

Cheerio

herefishy
23-01-2002, 01:18 AM
A-1, 10-roger-04 for AIYUB,

Personal attacks are unnecessary. It's like calling the factory tech line, and the service non-support professional treats you like an idiot!

"Well, excuse me Mr. SIR, if I didn't have a damn question to ask, you would be out of a job, wouldn't you?" If you want proof, call the Cornelius Ice Maker Technical assistance number, and just ask a question. Boy you'll sure be put in your place!

My motto is: "The only stupid question, is the one that isn't asked!".

Anyway, VSP, do you have an ongoing situation you are working on, or is this a general question for the satisfaction of your understanding of the refrigeration process?

I understand the questions of general understanding, of which I have posted in Fundamentals, "My Customer's Air Conditioner won't keep his beer cold!". Gibson has been the only one responding to me, I guess everyone else thinks I'm stupid, or maybe they think it's a good question and it's goin' to take them several months to make a determination. I Dunno.

see ya'

Dan
23-01-2002, 01:24 AM
LOL. I must say I enjoyed Mags comic relief.

A reciprocating compressor can indicate the direction of its rotation in a number of ways.

If it is spring mounted, just watch it torque on startup. If it is pad mounted you might want to look at the oil level in the glass during one rotation and then reverse its rotation (3 phase power) and see how the level changes. There is a "windage" that will show the oil higher if the bottom of the crank is rotating toward the sightglass, and the oil lowers, it is the converse.

Even on a single phase compressor you could probably watch the sight glass on repeated startups and develop some confidence regarding which way the crank is turning.

There are likely simple electrical ways to determine this as well. I am willing to bet that most single phase compressors are designed to operate in the same direction all the time. Clockwise? I don't know..... then from which end of the motor?:)

Likewise, I imagine there is a default rotation within a compressor-motor manufacturer when all three phases are connected in proper sequence.

Interesting question, but I wonder to what end?

Dan

Gibson
23-01-2002, 04:16 AM
vspiteri,
You must be referring to three phase compressors?

In every case I have experienced, reciprocating compressors don't care which way they rotate.

Centrifugal, screw and scroll compressors are all designed to operate in only one direction.

The best tool I ever purchased for determining rotation is a phase rotation meter I picked up from the local Trane parts center.

By reading the compressor's literature to identify it's rotation and using this tool you can correctly determine the direction of rotation prior to applying power to the motor. This enables you to reliably hook up the line wires properly.
But I'm from Canada eh! *S*

subzero*psia
23-01-2002, 01:53 PM
Well, here I go showing how daft I can be.

I never knew that any compressor was directionally specific. No matter which way the crank turns, the pistons still complete their stroke and the suction valve is still the suction valve so the discharge valve still does its normal job too. I don't understand the question, what am I missing?

I can see what Marc is saying though... if the oil flipper/spinner etc. is directional then I guess that would make the compressor directional if the compressor is expected to survive long. ;)

Frosty
23-01-2002, 06:38 PM
Speaking on behalf of Frank, who I have known 2.5 years now, I know that he wasn't being condescending (thank god for the Microsoft Word spell checker on my machine!!!) - he isn't like that! He was obviously speaking matter of factly!

He is right in the majority of situations, however, many 3-phase recips will run in either direction....with no mods. Other machines are directionally challenged!

As Gibson states, screws, centrifs and scrolls have to run in one direction and one direction only. I remember many years ago (when I was an apprentice), seizing a Bitzer screw compressor up at Chelmsford Ice Rink. The senior engineer and I basically sh*t ourselves, luckily, with the help of a very large crowbar and an even larger scaffold pole, we freed it off (halleluiah)

We had to have more drinks than usual at the bar that night....you know, to coax ourselves out of shock!!!! Well, that's what we told ourselves (hehe)

The machine had only span for a matter of seconds before grinding its rotors into the thrust housing.

The motto is......always check the rotation marking on the machine and seperate the compressor/motor coupling before doing a rotation check. In the case of semi's, the recommended procedure for checking rotation is to connect a suction guage to the inlet of the machine and 'flick' the starter so that the machine runs for a second or two. If the rotation is right, the suction guage will fall, if the direction is wrong, the guage pressure will rise - no damage to the machine will occur if you're sensible!

One more important think to remember....if the motor is star-delta, part-wind etc, rotation must be checked on each stage i.e. in star and in delta, although, if there is reverse rotation, the fuses will normally go - not always the case though....you have been warned!

frank
23-01-2002, 07:14 PM
:o

Sorry if I sounded like a school teacher - it wasn't meant to come out like that. I wouldn't call anybody a "thicko" either, we are all at different levels of learning and I still have a long ways to go.
Hope my apology is accepted???

Thanks for the moral support Frosty - by the way, how did you get that scaffold pole in your toolbox??or do you have a long thin one?? (now, now), and are you out of your apprentiship yet?

Frank:D

subzero*psia
23-01-2002, 10:50 PM
No offense taken by me, I freely admit... I've only seen one screw compressor in my life that I know of! LOL! :rolleyes:

I work primarily on the smaller stuff... my hat is off to you boys working on the bigg'ns!

You know that old saying... if you don't use it... you lose it. Well, I partly believe that, as I can testify to it. BUT... sometimes alittle reminder or nudge and much or some will come flooding back. Things just slip your mind if you aren't around it everyday.

I would love to work in Ammonia... those huge Niagras etc! Cold storage plants... would be to my liking!!:D

Abe
23-01-2002, 11:01 PM
Frank,

No apology necessary

Reeferjon
24-01-2002, 12:15 PM
In mobile Reefer's we mainly use an X4## type semi-hemetic recip compressor, the oil pump is georotational so if its on diesel or electric c/w or a/c it does not matter what the rotation is, this applies to nearly ALL transport Reefer compressors including vehicle AC type (rotating sqash plate).

BUT we now have a Scroll comp if its going the wrong way it lets you know and will last about 20 seconds.

Frosty
24-01-2002, 07:23 PM
Franky Boy, this is obviously the longest apprenticeship ever served!

Better get my arse into gear and start posting, smartish....I reckon one post every 10 minutes should see me catching up with Marc (amongst the many) in about 2007!

Frosty:D

frank
25-01-2002, 08:52 AM
:)

Aiyub, ask away!

Lesson learned!!


Frank

vspiteri
25-01-2002, 09:09 PM
Thanks to everybody for the movement that this rotation had created.

I would like to place some salt on the subject since some did understand what I mean, while others ?

As nearly most techs realized that this is a 3 phase unit and that I was mentioning a 90 to 120 kW compressor which is very different and very bigger than a fridge ( 240 watts) compressor which most of our forum techs are sounded for.

The rotation was concerned on the oil capacity, which plays the largest part in oil lubrification circulation and the capacity control system .

I never mentioned the pumping capacity with respect to flap valves but to the disk valves complete with high tension cylinder holding down springs and the unloading/loading system - this type of compressor has large valves - Trane - Vilter and others

This does make a diffence - To those who never worked with these large compressors, must note that the compressor will be changed against the manufacture maintenance documents while will guide the ref tech to connect the wiring cable from the contactors to the terminal block as per NUMBERING sequence respectively which will reduce and eliminate the risk and problems for rotaion - this proceduce will have the advantage that the technician will never need to control the sequence and the procedure will hold because the condenser fan rotation will stay as per commisioning.

This is why nobody ever ask any thing about rotation - I though the forum is made up of professionals and not by fridge techs only.

FOR THOSE WHO WANT TO LEARN SOMETHING

Source of trouble

Compressor indicates little or no oil pressure

Possibile causes

Oil pump reversing gear stuck in wrong position

Corrective steps

REVERSE DIRECTION OF COMPRESSOR ROTATION

Can we be professioally

Thank you

frank
25-01-2002, 09:45 PM
Maybe if we had a wider look at the problem at the start we could then offer more informative replies. Why doesn't the original question include all the information - is it because we are being tested???:confused:

vspiteri
25-01-2002, 11:19 PM
Frank

Sorry for the misunderstanding but there was no testing and all in good faith.

I was going to suspend my interventions in the forum because I noticed that the rest of the forum went on the wrong direction with the first reply to my question -

I though that the forum is professional ,which means that we do not assume but go on facts, making us more reliabile in our work and thoughts - good participation

I felt very sorry for those who had pulled the strings without contributing to the subject.

Hope that we will learn many good things from each other.

Frank ,by profession am a qualified marine engineer (few years at sea) and having 20 years experiance in HVAC equipment of the largest capacities being 320 to 400 tons of refrigeration (centrifugal and screw) and Plant equipment in the electronics manufacturing - latest and state of art technology in every sector , compressed air,DI water,cascades,tandems etc -

This is the reason that I don't like others to play strings with me and I will be active when the forum attidude will be up-graded

Thank you

Victor

Abe
25-01-2002, 11:45 PM
Hello all

I am glad that the dust is settling on this one,

Vspiteri, it is really good to see you posting, I wish you will continue to post, I hope I did not give the impression that " you asked a dumb question" I dont have the foggiest about these large machines that you guys handle, so I wouldnt be able to tell my onions from the potatoes about the credibility of your question...........but in the end I think you have astounded me with your calibre and understanding and I think it has enriched the forum.

Otherwise, all is well, we have a rough and a tumble now and again, but were all wedded by profession.........(hic !!! ) pun not intended!!! Hell, dont want to start another war!!!!

I mean we are all mates and at the end of the day all is forgotten over those Castles ...........( Marc will know what I mean)

And one last thing.........I hope Im not coming across as some wise old man like ole Abe Lincoln here, with designs on hijacking this forum, Webram, its (still) safe in your hands !!

Have a great weekend everyone

herefishy
25-01-2002, 11:54 PM
I kinda' feel partly responsible for engaging in the de-rail of the thread.

I did not really think that Frank was intending to be antagonistic. However I did respond to Aiyub, only in the sense of my personal experience with being on the other end of the stick, when I would like to know something in regard to my activities in the field.

Did we get to the point, anyway?

Respectfully,

The Fish......

subzero*psia
26-01-2002, 12:58 AM
Well I for one feel kind of OFFED. :mad:

I think EVERYONE assumed this was a three phase, but NOT ALL compressors are omni-directional... some WILL run and supply oil in either direction. That is a fact.

But... I do hope we see vspiteri posting again soon... this time with more facts for more professionalism so you can get the answer you were seeking. heheheh! :p

This was vspiteri's original question...

How can a ref technician note that the mechanical rotation of the compressor is in the right direction with a dual position oil pump and only one sight glass at the bottom of the crank case ?

And then the answer, aside from cracking everyone...


FOR THOSE WHO WANT TO LEARN SOMETHING

Source of trouble

Compressor indicates little or no oil pressure

Possibile causes

Oil pump reversing gear stuck in wrong position

Corrective steps

REVERSE DIRECTION OF COMPRESSOR ROTATION

Somehow I don't see that he answered his own question... little or no oil pressure does not necessarily mean the rotation is wrong... it is merely a symptom of several possible causes.... of which ONLY ONE did he post. Real professional... yep!YeeeHaww! Ride'm Cowboy!! LOL!!

Sorry, Fish... I know you live in Texas... no slight intended with the cowboy bit... just having fun with vspiteri!!

AND... I apologize to vspiteri... but you were alittle harsh on everybody that posted... and they were only trying to give you opinions. Everybody on this board is a specialist in one area or another. Some are extremists and it may even be possible that they are the best... don't take anyone to lightly. Just my humble opinion...

Gibson
26-01-2002, 06:01 AM
vispiteri..."Can we be professioally" ??? What?

What, may I ask, are you trying to say in your last post? Do I need an interpreter?

Oh! Was this a test? *LOL*

I thought there were some very good answers to your original post considering the lack of system information, compressor type and operating conditions.

I did wonder what a "dual positional" oil pump was though!

And that reference to a "reversing gear in an oil pump stuck in wrong position"?

Could you rephrase your last post?

Then again... Nevermind

Dan
26-01-2002, 01:33 PM
Life is short. Let's enjoy it.

Abe
26-01-2002, 11:34 PM
Me. Ive learnt my lesson too

In future Ill stroke my beard and read the posts with a wry smile
and NOT interfere in matters of which I have no knowledge about.

As was pointed out, every one is specialised in one field or the other, and every one deserves recognition and respect

I appreciate Frank was not antagonistic , and it was just taken the wrong way, so to you Frank, my humble apologies

And , it does help , when someone requires information to be as specific as possible, in order to recieve a valid answer

Look at my postings when I need help, I overdue it and put in useless information, which Im sure irks some members!!! But there goes.......

Best, use one of Fridgetechs refrigeration operating plant sheets which about covers all the parameters

This forum is a great "place", its not perfect, but show me anything else, ( apart from the Fridgetech discussion) which comes even close to bringing so many professionals from all parts of the world , and actively participating

So my motto for the day is,

Long may RE prosper!!!

Did I hear everyone say Halleluyah???

Terra all

Abe
26-01-2002, 11:40 PM
Mags, where are you??

Ive just decided, its more fun talking to our unfullfilled fridges and dishwashers, better then talking about rotation and pressures , and phases and things!!!

So if youre out there listening, lets catch up on our refrigerator freinds and try and make their short existence on mother earth more bearable

Byee

Mike Hopkins
29-01-2002, 02:35 AM
You fellas getting a little deep here now. Any way most of the little recips. I have run across are multi directional. However one case you should watch is where you have an older unit and say move it to another location and swap rotation. Now there may be enough wear from running in the "right" direction for so many years that now the oil pressure gets a little low when the direction has changed. Another case was where a contractor had condemned a 5HP recip. and we swapped it over a time or two and away she went to running again (had sat for several years).
I don't remember if we put it back "right" but it ran ok for several years after (customer for life). Best check with the manuf. if you don't know, trash one good sized screw or centrif. and you'll be crying the blues. Carrier 5H\5F manual does mention that rotation should be in direction of arrow on pump cover but then goes on to state that she will run in either direction and that proper rotation is to prevent confusion of the operator, that's a new one
to me. This oil pump reversing gear strikes a chord with me as to something I have heard before, Vspiteri care to mention a manuf. name, the first letter will do. Makes me wonder about the old thing about why does the bath water turn in a specific direction when going down the drain. Well I had to try it one night and found the direction can be manipulated by the shower spray head and it will stay that way.
My 2 sense.
Mike Hopkins