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Message ID: 18     Entry time: Wed Sep 23 13:34:04 2020
Author: JM 
Subject: Tuesday 22 September 

Turbo-pump Issue approximately 13:00 22/9/20.

While moving the baking octagon into position, the power connector became disconnected from the turbo pump. The pump controller provided the warnings of connector failure and high pump load (probably due to it reading the frequency of the pump as 0 Hz when disconnected and thinking this was due to a high pump load). I believe the valve then was slightly knocked causing a vibration in the turbo, which couldn't be corrected for by the controller as it had become disconnected. The result of this was the turbo noise growing louder (similar to the turbo in the edinburgh lab when venting). At the time I didn't know the connector had become disconnected, as it was still attached to the turbo, and due to the warning messages on the controller, noise of the turbo and lack of information on what had happend, I decided to close the valve connecting the chamber to the turbo and vent the backing line up to the turbo and in order to remove and replace the turbo. 

The chamber was in the high -6 mbar range when the valve was closed. The turbo was replaced with the second turbo which began pumping again (with the power connector properly secured this time) on 23/9/20. The turbo doesn't show any obvious sign of damage, the blades in it are free to spin with no hindrance, but we will have to get it tested by the vac lab to be sure. 

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