Compressor winding burnt frequently

[SPBDASAN]

Hi all,

We are providing one SEMI HERMATIC compressor for one project( in Ship) for Air con. but this compressor motor winding burnt frequently.Motor kw is 37 kw/440v. OLR range - 30~40A. this motor has Thermistor also. but its not protect winding to burnt. pls anyone give me solution for above.
Thanks

[nike123]

Problem is probably formation of acid in oil from previous burn-outs. You need proper acid treatment. Check this Copeland AE buletin (http://www.hvacrinfo.com/cope_ae_bulletins/TAE1105.PDF) for burn-out cleaning procedure.
If you did not done clean-up as described in that bulletin after previous compressor replacement, and your control/protection circuit is OK, then acid in refrigeration circuit is most likely the cause of subsequent burn-out.

Link fixed!

[ALLAHHOOPK]

CHECK THE STATE OF OIL CHAREGED.
ELECTRICAL CONTROL CIRCUIT.
MOTOR PTOTECTOR INSIDE THE TERMINAL BOX OF COMPRESSOR
MAGNETIC CONTACTOR etc.

[Peter_1]

Is motor VFD controlled?
Is there a filter/mesh screen installed in the suction?

[Peter_1]

Nike, the Copeland you provided link isn't working

[nike123]

Nike, the Copeland you provided link isn't working

Fixed!.........

[Yuri B.]

Do you rewind the compressor or put in place of the "dead" comp a new one? If the latter then the oil contains acid destroing winding"s insulation if the former then the rewinding is, probably, being made with improper materials. I dont rewind motors, but am sure insulation of the wires used, varnish, and what else rewinders work with differ from what is being used for conventional - not intended to be in contact with refrigerants - motors repair.

[GHAZ]

Hello yuri b the insulation on the motor wire is special its normally p200 and then the motor is dipped in insulating varnish and cooked in oven ,so it goes hard to proctect against any debri floating around which may damage it and also to stop coils from vibrating together and to protect against acid in the system , with acid in system the varnish breaks down with in days

[Yuri B.]

Stupid, on my part, questions: you do not switch a 50 Hz 400 V compressor to 60 Hz 440 V circuit? (in case it is not recoprocating one) the phase sequence control is present - as to its rotation direction?

[NoNickName]

Check the voltage with a data logger for surges, spike, over and under voltages.

[al]

nnn

what brand/type logger do you use?

al

[nike123]

nnn

what brand/type logger do you use?

al

Where did you see that he uses any logger?

Sorry al, I see now that you addressing this to nnn!

[al]

i just assumed from the fact that he recommended its use that maybe he had one himself?

al

[nike123]

......................

[NoNickName]

testo and fluke have good data loggers, or you may want to build one yourself with Xweb500 from dixell and 1 voltage converter. This way one can monitor the voltage on the internet.

[Yuri B.]

Gentlmen, will data logger be a direct solution of the problem? If SPBDASAN found at morning that just another comp is dead, would he be very happy to know the comp had died at, lets say, 4 AM from a voltage surge?

[Yuri B.]

In case the evil of acid in the system is absent, SPBDASAN need to think of a better direct current/voltage protection for the comp. Lay the control circuit through a relay putting up a min/max limit on the voltage (probably, 420/460 V), install an electronic current relay on the power wires, one with the time current controls (one control for the start - it will tolerate starting current, lets say for 5 sec, another monitoring working current, letting its deviation - to a sensible extent - lets say, for 3 sec). Thermistor is not redundant, also, but in case it is original to the comp, and is switched to an adequate controller (I once saw the control circuit of the magnetic contactor being just switched through the circuit of the thermistor!!! ) And what is the scheme for the powering the comp ? - I mean how many magn contactors are there 1 2 (3 I'v never seen for refrigeration)? Is all commutation right?

[Peter_1]

NoNickName, will the sample rate of an Xweb be fast enough to detect spikes? I doubt.
Your sampling rate will need to be high for this (in the range of minimum 400 Hz)
A datalogger like Xweb is only taking momentarily measurements, so if you measure just before or after a spike, you will not see them.
Scopes are working in the range of Mhz and even Ghz.

[Peter_1]

....- I mean how many magn contactors are there 1 2 (3 I'v never seen for refrigeration)? Is all commutation right?
And Start/delta start then?

[Peter_1]

And to see spikes and surges, you will need in my opinion a scope with a Fourier Analysis.

[Peter_1]

The original poster isn't even following his post, not so much interested in a solution for it. :rolleyes:

[NoNickName]

NoNickName, will the sample rate of an Xweb be fast enough to detect spikes? I doubt.
Your sampling rate will need to be high for this (in the range of minimum 400 Hz)
A datalogger like Xweb is only taking momentarily measurements, so if you measure just before or after a spike, you will not see them.
Scopes are working in the range of Mhz and even Ghz.

It probably isn't fast enough, but chances are that a surge or spike alone is not enough to burn a stator, so I think that an undervoltage or overvoltage is more probable cause. If this is true, a data recorder like xweb may be enough.
No need for exotic devices like FFT scopes or similar at this stage of investigation. But in principle you are perfectly right.

And for Yuri, no! This isn't a direct solution, because I'm not doing YOUR homework. This is just a piece of advice for starting your investigation. Or, if you want me to solve your problems, then you have to pay me.

[Peter_1]

Reason why I asked if his motor was VFD controlled http://www.achrnews.com/Articles/Feature_Article/d04a42a9a026a010VgnVCM100000f932a8c0____
But the original poster is not interested in a solution.

NNN, are the green Carriers also made in 'your' factory?
Is there a difference between the original blue and green ones?

[NoNickName]

NNN, are the green Carriers also made in 'your' factory?


Yes, they are



Is there a difference between the original blue and green ones?

No, they are exactly the same.

[Magoo]

Ship board generators are notorious for voltage fluctuations, and semi is probably part winding start.
I'll say no more, a situation for disaster, rather than surge protection a voltage protection control will trip system quicker, and say on failures.
magoo

[SPBDASAN]

Do you rewind the compressor or put in place of the "dead" comp a new one? If the latter then the oil contains acid destroing winding"s insulation if the former then the rewinding is, probably, being made with improper materials. I dont rewind motors, but am sure insulation of the wires used, varnish, and what else rewinders work with differ from what is being used for conventional - not intended to be in contact with refrigerants - motors repair.

we have changed with new Compressor, but it also burnt......
i hve attached that burnt compressor pic. pls give me some solution....

[SPBDASAN]

Is motor VFD controlled?
Is there a filter/mesh screen installed in the suction?


hi
Its not VFD controller. its part winding method starter.
i think dont hve a filter/mesh screen installed in the suction. could you give me solution....... is it must put?

[nike123]

we have changed with new Compressor, but it also burnt......
i hve attached that burnt compressor pic. pls give me some solution....

From that small picture it cannot be seen. Please post full quality picture to some picture hosting server (image avenue, image shack Tinypic etc...) and send link here since you cannot post big pictures here.

From this small picture it look to me that rotor is burned.:confused:

[SPBDASAN]

From that small picture it cannot be seen. Please post full quality picture to some picture hosting server (image avenue, image shack Tinypic etc...) and send link here since you cannot post big pictures here.

From this small picture it look to me that rotor is burned.:confused:

pls chk this link....mediafire.com/?sharekey=a9ae7ac3a65e524d7069484bded33bcd7ac0b17558e9e5d2

(pls add before .w w w ..)

[nike123]

http://www.mediafire.com/imgbnc.php/edbae9f52555dd9095cf58e3cd0b29986g.jpg

file:///C:/DOCUME%7E1/Ivan/LOCALS%7E1/Temp/moz-screenshot.jpghttp://www.mediafire.com/imgbnc.php/d59774f08e6f0f56cb9b6c654fc7193e6g.jpg
.........................................

[D.D.KORANNE]

MOTOR BURN OUT
Look for the following possibilities in a semi-hermetic part winding compressor .
a) how many times the compressor starts in an hour ? semi mfrs usually do not permit 6-7 starts .
b) debris logged in the windings cause winding insulation to scrape off while the windings flex when heated switched on
c) since power generators on ships usually experience dip in voltages & frequency , a zero load start up would reduce the kick voltage on windings.this can be achieved by a discharge suction by pass during start up .
d) use the part winding start up method rather than DOL to limit the start up kick on windings.
e) moisture in system , overheating are also possible culprits to look at for frequent motor burn-outs

[nike123]

Pictures are still unclear and this looks like stator one phase burn-out which (if confirmed) mean that you have problem with one or more of following:


Unbalanced voltage
Faulty contactor
Over voltage spikes
Faulty overload
Wrongly adjusted overload

and, if cleaning is not done properly after previous burn out.


acid in system

http://farm3.static.flickr.com/2304/3527494355_a4ed6018ed_o_d.png

[Peter_1]

I don't notice a 1 phase burn-out at all.

[NoNickName]

Neither do I

[nike123]

It appears to me that at 9 to 12 hours windings are black and from4-8hours windings are shiny. Rest from 12-4 hours I cannot see.
As I said, picture is unclear. Second is unusable.
Bandage should be removed and windings pictured with proper light.

[Peter_1]

we have changed with new Compressor, but it also burnt......
i hve attached that burnt compressor pic. pls give me some solution....

Looks like a Carrier /Carlyle 06EQ275 compressor or something similar.
Can you describe very precise how you replaced this motor, every step in it is important.
Is there an overload relay?
Is a thermistor fitted? How was it connected? Direct in line with the control circuit?
Were oil samples taken?

[Yuri B.]

Might not the squirrel-cage of the rotor be somehow shifted on its axel (poles of the rotor do not facing precisely stator poles?) The time delay of the second contactor engagement might turn critical too for your type of compressor.

[Peter_1]

In PW, delay as short as possible

[SPBDASAN]

Looks like a Carrier /Carlyle 06EQ275 compressor or something similar.
Can you describe very precise how you replaced this motor, every step in it is important.
Is there an overload relay?
Is a thermistor fitted? How was it connected? Direct in line with the control circuit?
Were oil samples taken?

Thermistor connected in control circuit. OLR range is 30~40A. motor is 37kw/440V. MCCB is max 100A capacity.
Mechanical side i need to ask my other dept. it take some time.

Oil is under testing. i havent get result.

[desA]

Perhaps a silly question. Do you perhaps have a new unit you could install?

The photos you show just look so incredibly dirty/messy. To my uninitiated mechanical eye, I'd be ever so worried to continue with the old system, until you can put it offline, through a detailed test regimen.

[nike123]

Thermistor connected in control circuit. OLR range is 30~40A. motor is 37kw/440V. MCCB is max 100A capacity.
Mechanical side i need to ask my other dept. it take some time.

Oil is under testing. i havent get result.

It is essential that motor windings are examined and found where burning has happened, because that will tell what is cause of burn-out. Remove winding bandage and picture windings in manner that is clearly visible what is burned. Than post picture here.

[Gary]

Check the voltage at each compressor terminal with the compressor running. Low voltage at any of the terminals indicates burnt contacts somewhere in the circuit, most likely the contactor(s).