Downloaded from https://www.everyspec.com MIL-STD-1311D METHOD 1227 TEMPERATURE/COOLING (Forced-air or fluid-cooled types) 1. General. When applicable, the following conditions shall be as specified in the TSS: a. Applied electrode voltages and wattage to be dissipated by the various elements. If dc potentials are specified, the maximum rms ripple shall not exceed 5 percent unless a wattmeter is used to measure anode-input power. If ac potentials are specified, a low-power factor wattmeter shall be used. Instrument burden, transformer and circuit losses shall be compensated for if such losses exceed 3 percent of the anode power specified. b.
Coolant type(s), flow (volume and velocity), direction(s) of flow, area and method of application, limit(s) of incoming temperature, system pressure (if other than atmospheric), supplemental cooling (if required for proper operation). c. Appropriate meters, indicators and methods of measurement. d. Accessories such as air socket or distributor, water (or fluid) jacket, auxiliary radiators (terminals, etc), and air directors or reflectors. When relevant, manufacturer's part number, catalog number, etc., for commercially available components shall be specified or complete detail drawings shown. 2. Procedure. a. Temperature rise.
With no voltages applied and with coolant system(s) operating at TSS conditions, observe the temperature (T initial ) at the specified location. Then, apply specified electrode voltages and adjust to obtain power same location as noted for T initial . The temperature rise, T, shall be within TSS limit(s). Formula: T = T final - T initial. b. "Hot-Spot" temperature. With specified electron voltages applied, and with specified power dissipation to the electrodes, the "hot-spot" temperature shall be observed after thermal equilibrium has been reached and shall be less than the maximum TSS limit. dissipation to the electrodes.
After sufficient time to establish thermal equilibrium observe the temperature (T final ) at the METHOD 1227 1227-1 19 April 1968