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Entry   First Lock with 2nd satge of amplifier : Motor issue ? , posted by Ronic Chiche at Optical room about mechanics Image1.png
    Reply   First Lock with 2nd satge of amplifier : Motor issue ? , posted by Ronic Chiche at Optical room about mechanics 
Message ID: 73     Entry time: Thu Oct 10 18:03:10 2019     Reply to this: 82
 Author: Ronic Chiche 
 Status: Fixed 
 Type: issue 
 Category: mechanics 
 Location: Optical room 
 Title: First Lock with 2nd satge of amplifier : Motor issue ?  

Global locking almost clean : tranmission and reflection are quite noiseless except the peaks at every 500ms.

During the amplifier 2nd stage lock, we experienced 2 strange behaviors :

- short "unlocks" every 500ms exactly all the time, during the whole lock process

- some PZT (in green on the picture) shift exactly synchronized with these "unlocks" (see the red circle).
these shifts are triggered by some OneFive motor move (Frep adjustment).

We tried to disconnect software activity (use the disconnect button on the software), to disconnect USB cable, to disconnect power supply of the motor controller box but none of these actions had an effect
=> still short unlocks every 500ms...

The amplifier 2nd stage seems to have small fan for the power supply... we can try to disconnect it.

We tried to turn on the 3rd stage which uses several fans for cooling the pump diodes... thus, one can see immediatly a big increasing in the PZT signal which tries to compensate the vibrations and quicly one loose the lock.
we have to think on how to suppress these vibrations.

 

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