Frick RTM120SEB8 vibration concern

[evapcoil]

Hi Guys
I've a strange vibration on one of my compressors, when it is running between 15% and 45-50% of capacity ,it vibrate like hell, I'm not very familiar with Frick compressors as I'd usualy worked with Stal compressors. I can definetly say that is not a problem related to liquid refrigerant coming back on the suction line as i switch the compressors with the spare unit and this ones is running fine... I'd contact York service and they siad that up to 11mm/s vibration value is fine , but I don't trust them very much as with our VSM89 chillers warranty problem ,they were more concern to cover them up instead to solve them.....
Anybody has any suggestion or comments?
I'm planning to open the compressor as an apple and replace the berarings and inspect the screw conditions...
Ciao
Evapcooil

[The Screwdoctor]

Hi evapcoil,

as far as my experience with frick compressors goes I'm certain that 11 mm/s is way too much. These compressors (when properly aligned and in good condition) can easily run between 1 and 3 mm/s. So check alignment and coupling (if it is rubber type inspect it very precise). If these are OK. Something must be wrong with the compressor.

Regards

The Screwdoctor

[evapcoil]

Thank You Doc
I'll check the coupling, regarding the alignment, the compressor is mounted directly on the electrical motor drive end flange so I don't think this should be bad....
Do You have any idea where i can find a service manual for this compressor???

[Paulajayne]

Vibration under partial load can be a sign of bearings going.

Get a long shafted screwdriver and when the vibration is occuring place the blade on to the compressor and the handle to your ear. By trying various places you should be able to pinpoint the vibration.


Paula

[evapcoil]

Actually, I'm thinking to through a complete overhaul of the unit as the vibration are at 14mm/s and the solution that Frick?York suggest is to put some weight on the discharge pipe??????????
I'll keep You posted....

[The Screwdoctor]

That would be nice, put some weight somewhere and all your problems are solved. What kind of advise is that??? You made the right decision to strip down the compressor. Something must be wrong with bearings, rotorpair.

The Screwdoctor

[TXiceman]

Sounds like you need to find a new Frick service center. They are just blowing smoke up your skirt to make you go away.

If you are getting these vibration levels at part load, what levels are you getting at full load? Also, at what frequencies do the vibrations occur. Are they at the driven speed or are they at a harmonic? Is it at 4 times the male rotor speed?

If you are getting a lot of vibration at 4 x the male rotor speed, this is you primary pumping frequency or rotor pass frequency and this may well be a gas induced vibration due to resonance in the discharge line or oil separator.

If the vibration is out in the 100,000 CPM range, it is bad rolling element bearings.

Vibration at part load can act strange when you get some excessive slide valve wear at a part load point. The slide valve can rock and eventually get to the point of contacting the rotors. In this case you can also hear the noise level has increased. Excessive slide valve wear can be caused by unsteady load controls, ie., the controls are not tuned correctly and lets the compressor constantly hunt.

Ken

[404cab]

Hello,

Is your compressor and XJF 120 from Frick, if yes, open the thrust bearing cover on the back, and look if the thrust bearings on the male or female side have been rotating on the sleeve distance.

If yes, then complete compressor overhaul is needed.

What application and refrigerant is it working on ?

[Industrial tech]

Had a similar problem, is there lots of foam in the oil seperator as well? Is this a liquid injection cooled machine?

[evapcoil]

Hi guys
sorry I was absent for a while without reading the forum, the compressor is installed in a 0°C setpoint plant using R407C refrigerant.
No ,I don't have a lot of foam in the separator and I don't have the liquid injection.

[hammurabi]

11mm/s RMS is just the requirement of ISO 2372.

agree with Txiceman!!!

[Frickman]

What size compressor is this? TDSH? SGC? XJF? BOOSTER, HIGH STAGE?

[subb-zero]

don't strip, first uncouple the motor from the compressor then have a vibe test done on the motor or check it yourself.

[Frickman]

if this is a 231 mm compressor they do have a very bad nosie in this slide valve range. Frick has figured out the problem and still use this compressor. all it is, is a gas hormonic in the screws them selves. I would have a vibration done in it anyway at that % slide valve.