1. Slide 1UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE UCSB 4-Hybrid Thermal Test System Status Peltier T/E Element Failures 3 September 2004

2. Slide 2UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE Peltier Failures Two peltier thermoelectric units have failed over the past year. à February 2004 à August 2004 Units exhibited reduced thermal efficiency resulting in longer hybrid test cycle times à 65 min vs 40 min à Distorted tygon exit hose Replacing with new units restores short thermal cycle time.

3. Slide 3UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE Heat Exchange Cooling Water Flow Rates à 4 L/m suggested by Supercool à 1.3 L/m current use Measured cooling water exchange rate à 6 deg C at 1.3 L/m at full power

4. Slide 4UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE Peltier Failure Mode Degradation of thermoelectric element due to overheating à Nominal Input Power = (24v*12A)=290 watts à Current Usage = (24v*14a)= 336 watts (+16%) à 80 deg C Thermal Interlock currently in use –need to test functionality It should not be possible to power up Peltier element without cooling water flow.

5. Slide 5UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE Future Plans Current Peltier Interlocks à 80 deg C thermal switch on unit à Software has peltier current locked to water flow Need additional hardware interlock in the event of a software or PC failure.

6. Slide 6UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE Flow Interlock Peltier power will be locked to cooling water flow à Use existing flow sensor à Electronic threshold on flow sensor output set to >1 L/m, if lower then power relay drops out à Comparitor/Relay board to mount on existing sensor interface panel.

7. Slide 7UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE Flow Interlock

8. Slide 8UCSB CMS Weekly Status MeetingCMS 4-Hybrid Test System Sam Burke EE Other Plans Use rigid Peltier exit line back to chiller Reduce temperature of cooling water Consider reduction of peak current by 5%