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--- equipment:chiller [2018/12/01 05:43] – [mcmaster] mcmaster
+++ equipment:chiller [2025/08/04 21:23] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 mcmaster equipment notes. Both broken when I got them
+====== TEC misc ======
+Failure modes?
+Can they fail open? Maybe not (assuming the wires are good). I think all of the elements are in parallel
+https://electronics.stackexchange.com/questions/261655/what-happens-when-a-peltier-fails
+Firstly, it appears that peltiers often slowly decline according to the referenced article, with increased resistance and decreased heat pump capacity.
+Therefore, my proposition is that in a typical heating application the heat produced by a perfeclty-shorted 100W peltier would be the equivalent of a 50W, poorly back-insulted, resistance element.
@@ Line 5: / Line 18: @@
 Power supply: roughly 12V @ 8A.
+TODO:
+  * Try cooling using external pump + power supply
@@ Line 17: / Line 33: @@
 Measured one TEC: 4V @ 1.4A start voltage
+TODO:
+  * Verify expected resistance (10 * 2.4 ohm => 24 ohm)
+  * Try cooling using external power supply + pump
+  * Backup PIC firmware?
+    * Might also be useful to figure out serial protocol
 ===== mcmaster =====
@@ Line 35: / Line 57: @@
 </code>
-I found DT12-4 and DT12-8 datasheets. Looks like linear relationship. Notes:
+I found DT12-4 and DT12-8 datasheets. Looks like linear relationship. Interpolated datasheet:
   * dtmax: 66 (27C), 74 (50C) C
   * Qmax: 54 (27C), 58 (50C) W