Rana thinks we can do better than 18 W heat load on the vacuum can. The insulation seems to have good cover all the way around but I want to see objectively where heat is leaking out.
The vacuum can heaters have been hooked up to a 30 V ~0.5A supply (P=V^2/R=30^2/50=18W). This will be left overnight so that the assembly can come up to temperature. I will have a look tomorrow with a thermal imaging camera to see if heat leakage points can be spotted.
---
The RTD 100 Ohm thermal sensor that was hooked up to the 966EN-4006 acromag card had been moved to monitor the air temperature within the tent. The LIGO temperature sensor interface board (see chain of posts starting at PSL:1730) was reconnected to power, the pinouts are tabulated below. One of the AD590 sensors (LEMO#6) was routed to the 8th input of the Acromag ADC a new channel was created in the data base (C3:PSL-VACTEMP_MON1) to monitor the vacuum can temperature. I'm not entirely sure if Frank selected good metal film resistors for this circuit (see PSL:843), he was only using this for diagnostic monitoring. Might need to switch to the J5 later as this one appears to at a calibrated value that makes sense when I tested it.
A frame builder would be good right now to log this data.
Pin outs of the DSub-9 connectors on the Temp sensor board:
Pinout Temp Sensor Board SubD-9 (#1)
Pin number |
Corresponding LEMO socket |
Voltage at 293K for AD590 |
1 |
GND |
|
2 |
GND |
|
3 |
GND |
|
4 |
GND |
|
5 |
NC |
|
6 |
J1 |
-8.54V |
7 |
J2 |
-8.54V |
8 |
J3 |
-8.54V |
9 |
J4 |
-8.54V |
Pinout Temp Sensor Board SubD-9 (#2)
Pin number |
Corresponding LEMO socket |
Voltage at 293K for AD590 |
1 |
GND |
|
2 |
GND |
|
3 |
GND |
|
4 |
GND |
|
5 |
NC |
|
6 |
J5 |
2.93V |
7 |
J6 |
2.93V |
8 |
? or NC |
|
9 |
Fixed voltage |
-10.82V
|
|