Order this information in Print

Order this information on CD-ROM

Download in PDF Format

     

Click here to make tpub.com your Home Page

Page Title: Section III. PRINCIPLES OF OPERATION
Back | Up | Next

Click here for a printable version

Google


Web
www.tpub.com

Home


   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Combat
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
USMC
   
Products
  Educational CD-ROM's
Printed Manuals
Downloadable Books
   

 

TM 55-6695-220-13&P Section III.  PRINCIPLES OF OPERATION 1-8. THERMOCOUPLE TESTING SECTION. 1-8 a. The tester may be visualized as consisting of two sections: Thermocouple Thermometer Testing Section and the Resistance Thermometer Testing Section.  (See Figure 1-2)  The millivoltage source shown is comprised of a 1.5 volt dry cell battery, two current limiting rheostats, a precision multiple-tapped, voltage divider network, and a voltmeter.  The operator standardizes the current flowing through the network by adjusting the COARSE AND FINE RHEOSTATS and observing the pointer deflection of the VOLTMETER.  When the pointer is coincident with the red line on the dial, the precision 27 discrete millivoltages reach their calibrated values.  The proper precision millivoltage tap is selected for output by setting the pointer of the TEMPERATURE SELECTOR SWITCH to the desired temperature, while taking note of the thermocouple material associated with the three colored sectors.  Precision resistance of 2, 8 or 22 ohms is further added in series with the source as shown by positioning the RESISTANCE AND VOLTAGE FUNCTION SWITCH.  This resistance simulates the actual resistance characteristics of the thermocouple junction and the aircraft wiring lead resistance. Figure 1-2.  Thermocouple Section Flow Diagram b. The function switch when placed in the LEAD RESISTANCE position energizes the null-balance bridge circuit, as shown, within the tester and converts the VOLTMETER into a null-galvanometer operation.  The LEAD RESISTANCE SWITCH is positioned to the resistance shown on the dial that corresponds to the expected nominal resistance of the aircraft's thermocouple wiring.  The LEAD RESISTANCE ERROR CONTROL can be rotated to obtain up-scale voltmeter readings on either side of the null condition.  The resistance error shown on the dial, either high or low, after the METER SENSITIVITY SWITCH has been depressed to more accurately determine the null condition represents the difference in resistance between that of the precision resistor in the bridge leg and that of the aircraft circuit. 1-9

Privacy Statement - Press Release - Copyright Information. - Contact Us - Support Integrated Publishing

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business