View Full Version : Sabroe 163 mk2 manual vi with angular position transducer fault

22-04-2016, 10:42 PM
Hello Engineers,

I am brand new to the forum, I hope that there is someone that has knowledge on the sab 163 . I have an issue with setting the Vu. I have followed the manual to try to gain a Vu of 4.5 which is 42 turns. I can only get 43 turns all the way to the end of the vi adjustment screw which when run shows a vi of 3.5 . It almost as though the capacity slide is able to open up to far, but I am unsure as to why this is with the vi spindle set correctly?. Any help gladly received.

23-04-2016, 12:32 AM
I have a Mk3 manual if you need.
Assuming we have same manuals, page 73 notes to set indicator a 40 deg below horizontal when fully unloaded, this is zero position with a normal duty compressor.
If you have a single stage compressor, possibly economized for freezer of low temp duty, it may have a spacer in it to prevent it unloading to much causing other issues (page 75).
If that is the case, see page 75, it will only unload to approx 30%, which means scaling on indicator glass could be out to your mechanically set Vi..
I have not had to deal with this set up but manual does not describe set up for this scenario.
I think indicator should be set as normal, 40 Deg below horizontal when fully unloaded, then zero be adjusted to suit.
When compressor fully loaded scale will be correct.
At the end of the day the 42 turns anti clockwise (or fully turned anti clockwise, then turn clockwise 1/2 turn) on manual Vi adjusting screw will mean with out doubt Vi is set to 4.5 VI

At the moment indicator shows Vi of 3.5 but this is past 4.5 setting, so believe it is really 100% loaded or close to it.
If it was a worn indicator spiral rod or drive pin driving indicator, it would possibly show a lower Vi than really is on indicator.

Can we ask running conditions you are running at & refrigerant used.
Have you changed it's duty from something else?

23-04-2016, 09:23 AM

The amps on the machine when run fully loaded are 235 amps which is the same on the compressor next to it. It runs at 10 bar discharge and 0 bar suction generally for a freezer plant operating a store temp of minus 20. The When the compressor is unloaded it appears to be correct going back to the correct zero point on the indicator. Although that is assuming that it is in the correct position as i adjust the dial plate to set it up as described in the book in the beginning
I understand what you are saying if the vi spinal is all the way back minus half a turn then that would suggest we have the max vi.
It is just it does not read 4.5 and before it was sent for overhaul it read correctly. In our manual it shows the spacer ring as being the housing of the capacity slide plate which sounds confusing, do you know if this is correct as I would have imagined that a spacer ring would sit inside the column in front of the capacity slide plate that the spindal is rotated by or positioned on the slide somewhere.


23-04-2016, 11:18 AM
I sent you a few pictures that might help with description etc.
This machine on that duty should have the spacer from all the information I have.
Can you check machine that is OK (reading 4.5Vi when fully loaded) by fully unloading it to see where it stops at minimum load.
That might indicate 0% starting point so 4.5 Vi lines up at full load.
Both compressors should unload to same point whether it 7,8 or 9 o'clock position etc

The overhauled compressor should have same degrees travel as "normal" other compressor.
If it rotates or travels more maybe they installed new spiral rod with incorrect helix, or installed new glass with different scaling.
If spacer is not in it & you set it per instructions, it still should stop at 4.5Vi

23-04-2016, 06:10 PM
I have asked about whether they installed a different spinal or indicator glass as this is what the fault seems to show, they have told me the parts are all the same as before the service. The OK machine dial travels from 0% to 4.5 in the vi.