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Thread: Three Phase Compressor
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12-10-2005, 09:06 PM #1
Three Phase Compressor
Will A 3 Phase Compressor Run Ok In Both Directions?
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12-10-2005, 09:07 PM #2
Re: Three Phase Compressor
It depends on the type of compressor.
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12-10-2005, 09:11 PM #3
Re: Three Phase Compressor
Yea ok,will have to check that. It ran ok ,possibly a bit noisy! but the temperature was dropping.
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12-10-2005, 09:31 PM #4
Re: Three Phase Compressor
A Scroll can only run in one direction
A recriprocating can be run in either..........
But look at the oil glass, if oil is squishing about, foaming...then change phases
This is what Ive been told....
I await a "qualified" viewAny opinions, statements and facts expressed in this message do not constitute legal advice in any shape or form and is given for a general outlook in nature. You are advised to seek appropriate and specific professional assistance from a regulated and authorised advisor for definitive advice.
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12-10-2005, 09:36 PM #5
Re: Three Phase Compressor
Cheers aiyub. Lang may u lum reek.
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12-10-2005, 09:41 PM #6
Re: Three Phase Compressor
Hi
This is my first post, I have been looking in on this forum for some time and finally feel I have something to add.
Screw compressors don't work with the incorrect DOR, or at least not for long. Recip's can run but the oil pump probably only works correctly in one direction.
Normally if the DOR is critical it will be marked somewhere.
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12-10-2005, 09:43 PM #7
Re: Three Phase Compressor
All compressors, apart from scrolls can turn to both directions.
On some of the open ones, there is a rotating direction, marked with an arrow.
Chemi
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12-10-2005, 09:47 PM #8
Re: Three Phase Compressor
Thanks. Pardon my ignorance though, but how can you tell which way a compressor is running?
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12-10-2005, 09:49 PM #9
Re: Three Phase Compressor
You can't.
Only on open ones.
Chemi
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12-10-2005, 09:53 PM #10
Re: Three Phase Compressor
Originally Posted by joeslad
The gauges will show high and low side pressures. If you connect gauges to a scroll compressor running the "wrong" way then you do not see any compression taking place and therefore, no refrigerating effect.
On a recip compresor you will see compression taking place no matter which way the compressor is running
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12-10-2005, 10:41 PM #11
Re: Three Phase Compressor
As someone said earlier, Screw compressors should only be operated in one direction! They are not bi-directional.
The manufacturers will have a direction of rotation arrow provided on the compressor. Open drive screw compressors should have the coupling taken apart for the pre-start direction check. With this method you are only checking the motor direction, not the compressor.
After the correct direction has been verified, install the center member in the drive coupling.
Most open drive reciprocating compressors will operate in either direction. The manufacturer may have a preference due to the belts.
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12-10-2005, 11:49 PM #12
Re: Three Phase Compressor
The only compressor that will run in either direction is a recip without an oil pump. Even then, some larger recips have uni-directional oil pumps and on those the direction is important.
Screws, Scrolls, Centrifugals and Rotary are all designed to operate in one direction only.
If it is critical - there will be an arrow.
If all else fails, read the instructions.
________
Chevrolet pickup truckLast edited by Argus; 07-02-2011 at 08:39 AM.
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13-10-2005, 01:13 PM #13
Re: Three Phase Compressor
A lot of the milk vats around this neck of the woods have Terry open drive compressors
PJS or VS
They can run both ways but there is a recommended rotation direction. From what I have heard it uses a dipper connected to crankshaft which picks up oil, If operated in reverse it doesnt pick up enough oil.
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13-10-2005, 05:08 PM #14
Re: Three Phase Compressor
Again how do you defined the rotation is correct or not correct for a refrigerant cooled screw compressor?
As mentioned from above types of compressor like scroll,screw,centrifugal etc. can they afford to be rotate the oppose direction just for a rotation test?Will it damage to any internal mechanical parts or gear?
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13-10-2005, 05:28 PM #15
Re: Three Phase Compressor
In some, there is internal clutch, some will make noise but no suction.
Thats how. It will not damage them if you check it in the first start.
Chemi
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13-10-2005, 06:20 PM #16
Re: Three Phase Compressor
A screw compressor can be used to generate power if gas is expanded through it backwards.
But...The screw packages have check valves on them, which prevent reverse gas flow!
On any open drive screw compressor, the motor should be uncoupled from the compressor for the rotation test to prevent damage.
Originally Posted by Temprite
Other compressors that have an oil pump are forced lubrication and have internal oil passages drilled in the crankshaft and connecting rods to allow oil flow. Also required for shaft seals in open drive compressors.
The semi-hermetic reciprocating compressors (Copeland, Caryle, and Bitzer, I think) do not have any required direction of rotation. The oil pumps are reversible.
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13-10-2005, 06:53 PM #17
Re: Three Phase Compressor
Joeslad,
how can you tell which way a compressor is running?
Amprobe used to make an add-on adapter that was called a phase sequence adapter. This was used to verify the direction of rotation on the Dunham-Bush vertical screw compressors.
I found some other ideas in the links below:
http://www.engineeringtalk.co.uk/news/flu/flu183.html
http://www.fluke.com.sg/sgen/product...FlukeSingapore
http://www.fluke.co.uk/comx/pubs.asp...stit-t1&page=1
http://www.testsell.co.uk/displaypro...ence+Detectors
There are probably more, but this should give you a good start.
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13-10-2005, 07:03 PM #18
Re: Three Phase Compressor
On new machines where rotation is crtical such as screws, scrolls and centrifugals a phase sequence device is used in the control circuit and it will not allow the machine to come on line if rotation is not correct.
Cofreth, yes the compressor may damage due to a wrong direction, some manufacturers says not to jog the machine even for to check the rotation, the phase sequence must be checked before to connect the power supply.
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13-10-2005, 07:07 PM #19
Re: Three Phase Compressor
Is it possible that members can post pictures of "screw compressors" in situ
Im not really wanting to see manufacturers type, brochure pictures, but actual live models all set up that you probably have worked on , and taken a snap shot of.
Only reason I ask, this thread has developed quite nicely and with it the technical aspects discussed has accordingly advanced.
For those of us, who dont normally get on hands on the bigger stuff, it would be enormously helpful to see pictures.
ThxAny opinions, statements and facts expressed in this message do not constitute legal advice in any shape or form and is given for a general outlook in nature. You are advised to seek appropriate and specific professional assistance from a regulated and authorised advisor for definitive advice.
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13-10-2005, 07:27 PM #20
Re: Three Phase Compressor
Abe,
For those of us, who dont normally get on hands on the bigger stuff, it would be enormously helpful to see pictures.
But yes I will try to get some pics.IF AT FIRST YOU DON`T SUCCEED.
DESTROY ALL EVIDENCE THAT YOU TRIED!
and go get a cuppa
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13-10-2005, 08:05 PM #21
Re: Three Phase Compressor
Originally Posted by mark375It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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13-10-2005, 08:12 PM #22
Re: Three Phase Compressor
Originally Posted by Peter_1
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13-10-2005, 09:39 PM #23
Re: Three Phase Compressor
Aiyub,
Here are some pictures from a project I worked on. These were installed in a large chemical plant. These are operating with R-22.
Picture number 6 is a large propane screw compressor package going into the paint booth. I did not have pictures of this installed, but it is an impressive picture.
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13-10-2005, 10:50 PM #24
Re: Three Phase Compressor
1. There is no negative impact on durability caused by operating three phase Scroll compressors in the reversed direction for a short period of time. However, after several minutes of operation the compressor’s internal protector will trip. Reverse operation for over one hour may have a negative impact on the bearings.
2. Screw compressors may only be operated in one direction of rotation otherwise substantial mechanical damage will occur.
• Connect a compound gauge to the suction service valve,
fully front seat the suction service valve and then open one full turn.
• Bump start the compressor - switch on then
off quickly (approximately 0.5 to 1 second).
If the direction of rotation is correct the suction
pressure will drop immediately.
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13-10-2005, 10:52 PM #25
Re: Three Phase Compressor
Bitzer screws.Bitzer.jpg
Bitzer1.jpg
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14-10-2005, 04:03 AM #26
Re: Three Phase Compressor
Hi Guys,
I went surfing for additional information on the reversible oil pump issue.
http://www.carlylecompressor.com/PDFs/06D06E/06de_2.pdf
http://www.copeland-corp.com/america...us/oilpump.htm
http://www.bitzer.de/document/doc.php?DCODE=KP-525
(see page 3 in the PDF)
All of these have reversible oil pumps.
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14-10-2005, 07:35 PM #27
Re: Three Phase Compressor
Iceman.. Vaidas
Thank you, great pictures...........Any opinions, statements and facts expressed in this message do not constitute legal advice in any shape or form and is given for a general outlook in nature. You are advised to seek appropriate and specific professional assistance from a regulated and authorised advisor for definitive advice.
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14-10-2005, 08:44 PM #28
Re: Three Phase Compressor
Aiyub,
Your welcome.
I'm happy I could find some to post for your review.
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15-10-2005, 09:52 PM #29
Re: Three Phase Compressor
'Most' three phase reciprocating compressors have a reversible oil pump such that the compressor can be operated in either direction without detriment to the compressor.
Scroll compressors only work in a single direction which can be seen when you attach a gauge set, if rotating correctly you will have normal suction and discharge pressures but if running in reverse there is little or no difference between suction and discharge pressures.
Screw compressors only operate in a single direction and when a gauge set is attached will likely show a small reversal of suction and discharge pressures if running in reverse. This happens because the screw compressor is a positive displacement type pump and a certain amount of refrigerant will be moved backwards through the system if the compressor is backwards. How much depends on the system design and what checks are in place in the overall system.
Compressor manufacturers build compressors for standard ISO rotation RST and you should use a phase rotation meter to verify the phase connections prior to installing, then install as per the compressor manufacturers instructions for phase rotation.
Originally Posted by joeslad
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15-10-2005, 09:58 PM #30
Re: Three Phase Compressor
Carlyle 06D and 06E compressors for R134a have a crankshaft driven gear oil pump which is reversible the same as the vane toil pumps originally installed for R12/R22
Originally Posted by mark375
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17-10-2005, 02:24 PM #31
Re: Three Phase Compressor
But... not if the screw package is being used to generate power
When a twin screw is used as an expander, the flow through the compressor is reversed. This transfers the axial bearing load to the opposite end of the compressor.
I believe the check valves would still be required on expansion service, since the expander would still probably back-spin during shutdown.
In theory, I completely agree with you. In practice, if the compressor is built for compression service the compressor should not be ran backwards for expansion.Last edited by US Iceman; 17-10-2005 at 02:25 PM. Reason: text editing
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17-10-2005, 02:48 PM #32
Re: Three Phase Compressor
Not all recips are birotational, phase conection determines rotation and if it is rotation sensitive the Operation Manual will tell you.
Most recips less than 25HP are not rotation sensitive.
Steve
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17-10-2005, 05:40 PM #33
Re: Three Phase Compressor
Hi Steve.
I have changed through the year, a few 60 hp Trane compressors.
Nothing about rotation.
Please enlighten me, how can one tell the direction of rotation in semi hermetics?
Chemi
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04-12-2009, 07:00 PM #34
Re: Three Phase Compressor
Chemi
How is this for a late answer.
The rotation sensitive recip commpressors that I've seen were old open types that were Trane or Carrier maybe Worthington. These were like older than me and I'm 55. I belive the issue was non reversing the oil pump.
I can't think of any new or newly remans that rotation is an issue.
I don't know how you would tell the rotation on a semi however you would check for proper rotation (if required) with a phase sequence meter.
I think its cheap insurance to check.
So sorry for the super late response
Steve
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