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--- equipment:chiller [2018/12/01 05:30] – mcmaster
+++ equipment:chiller [2018/12/01 05:52] (current) – [TEC misc] mcmaster
@@ 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 10: / Line 26: @@
 AKA: Silicon Thermal Powercool CH250
+something like 28V @ 5A
+TECs in series
+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 =====
+TEC:
+<code>
+marlow
+industries, inc.
+(/P)
+DT12-6 L
+USA
+- +
+</code>
+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
+  * Imax: 5.55 A
+  * VMax: 14.7 to 16.4 V
+  * AC resistance: 2.4 ohm
+===== Thread =====
 Reference: https://photonlexicon.com/forums/showthread.php/6533-Thermotek-Chillers-Exposed!-(TEC-Question)
+  * Well I finally concluded that the 10 TEC's inside the unit were 45W each with an Imax of 5A. So I found a set of 10 45W TEC's on ebay for $65 with an Imax of 3A. Obviously more efficient. Nothing wrong with that!  So, I just received the new TEC's last night and proceeded to put the ThermoTek chiller back together again.
   * let them sit for a bit then check the resistance of the good modules
   * i found the 40-60 watt TEC's to be around 2.8 ohms. 140 watt 0.8 ohms
@@ Line 18: / Line 75: @@
   * Anyway, It does sound like you have a bad TEC PS especially if the relays are engaging. Any funny smells at the board? Maybe one of the transistors on the heatsink or one of the filter caps are smoked.
   * External power to the TEC's 22 volts @4 amps this thing gets the water temp down fast!
-  * Well I finally concluded that the 10 TEC's inside the unit were 45W each with an Imax of 5A. So I found a set of 10 45W TEC's on ebay for $65 with an Imax of 3A. Obviously more efficient. Nothing wrong with that!  So, I just received the new TEC's last night and proceeded to put the ThermoTek chiller back together again.
-something like 28V @ 5A
-TECs in series
-Measured one TEC: 4V @ 1.4A start voltage