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Entry  Sun Jan 14 16:52:53 2018, Craig, DailyProgress, TempCtrl, High Current Draw for Vaccan Temp Control Causing Nonlinear Voltage Spikes 20180114_CTNLab_TempControlSpikes_6hours.png
    Reply  Sun Jan 14 20:40:26 2018, awade, DailyProgress, TempCtrl, High Current Draw for Vaccan Temp Control Causing Nonlinear Voltage Spikes 
       Reply  Mon Jan 15 21:35:14 2018, Craig, DailyProgress, TempCtrl, High Current Draw for Vaccan Temp Control Causing Nonlinear Voltage Spikes 
          Reply  Tue Jan 16 10:57:50 2018, Craig, DailyProgress, TempCtrl, High Current Draw for Vaccan Temp Control Causing Nonlinear Voltage Spikes 20180116_OvernightVaccanReheat.png
             Reply  Tue Jan 16 19:10:29 2018, awade, Craig, DailyProgress, TempCtrl, Debugging vac can heater circuit: heat, oscillations, leaking current. 20180115_HeaterCircuit.pdf2018-01-16_19.08.57.jpg
                Reply  Wed Jan 17 23:40:15 2018, awade, Craig, DailyProgress, TempCtrl, Debugging vac can heater circuit issues: oscillations everywhere 2018-01-17_21.20.58.jpg
                   Reply  Mon Jan 22 20:30:11 2018, Craig, awade, DailyProgress, TempCtrl, Debugging vac can heater circuit issues: oscillations everywhere CTN-Lab-Heater-Circuit.pdf
                      Reply  Tue Aug 20 11:19:35 2019, anchal, DailyProgress, TempCtrl, Vac Can Heater Circuit repaired CircuitCloseup.jpgBoxOverview.jpg
                         Reply  Wed Aug 21 16:17:47 2019, anchal, DailyProgress, TempCtrl, Leave the Heater Circuit Alone! 
          Reply  Tue Feb 27 14:17:13 2018, Aaron, DailyProgress, TempCtrl, High Current Draw for Vaccan Temp Control Causing Nonlinear Voltage Spikes 
             Reply  Wed Feb 28 10:20:40 2018, awade, DailyProgress, TempCtrl, Heater and temperaure sensors in cryo lab GroundingDoGroundingDont.jpg
Message ID: 2398     Entry time: Wed Aug 21 16:17:47 2019     In reply to: 2395
Author: anchal 
Type: DailyProgress 
Category: TempCtrl 
Subject: Leave the Heater Circuit Alone! 

I aligned the south cavity today achieving a nice 70% mode matching. While doing so, I realized a big issue that was gone unseen before the heater circuit blew up. I saw that since the vacuum can temperature control was active and was making a lot of jumps here and there all over the 1.5 A range, the Sorenson power supply isn't so good in keeping up with such sudden current changes. In effect, I think the Vacuum Can Heater's PID control signal gets coupled to the overall power supply coming from Sorenson.This +- 24 V rail was connected to EOM drivers earlier. Because of the poor design of EOM drivers, the EOM's are constantly at a DC voltage of +24V from this Sorrenson Power supply with only a passive filter. I could see today that when vacuum can PID was on, the laser frequency was haphazardly changing making it much more difficult to align the cavity. I was able to align it in minutes once I switched off the vacuum can PID.

So moral of the story is, keep the vacuum can heater circuit alone and Sorrenson Power supply is exclusive for it.

I shifted the EOM driver's power supply to Kepco which supplies for other rack-mount electronics as well.

Quote:
  • I noticed now that the Sorenson power supply was supposed to be exclusively used for these can heate drivers. It is presently being used for driving EOMs also. I'll switch the EOM drivers to the other Kepco supplies.

 

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