Document JJL669KQr2opyK1jeKae84XEO

I DIRECTIONS FOR TEST NO. 14-36-41 suBJECT:_____ Dielectric Constant of Liquid Aroclor M ETHOD:__________:________' : '_________________________________ .v ' Scope ' This method applies to mineral oils end oil substitute used for Insulating purposes. V Apparatus V v- Capacitance Bridge General Radio Co., Type 716-AM Cathode Bay Mull Detector ; H " " Type 707-A Oscillator * " * Type 6o6A Constant Temperature Oven Cenco-DeKhotlnsky #95050 . Variable A|jr Condenser General Radio Co., Type 33^-* 1500 00. Byrex Beaker ^ Procedure -` Electrode and beaker must be cleaned as directed under "Clean ing Apparatus for Dielectric Constant", and be at 100*%. , Heat Aroclor in the can to 105C. Pour over electrode until | plates and ceramic Insulation is covered. Connect leads. Stir vlth | thermometer outside oven until temperature reaches 101; place In I oven which ha* been carefully adjusted to 100C, At the time sam1 pie le placed in oven ltB temperature should not have fallen below 90C. Connect leads to capacitance bridge, observing that the lead from insulated side of condenser goes to Insulated terminal on bridge. Balance bridge carefully according to direction under "Balancing | Capacitance Bridge". Until Aroclor and oven temperatures have bej come Identical the bridge balance will constantly shift. After j oven temperature reaches 100^., maintain bridge balance until no i pronounced shift Is evident. Record reading of capacitance scale multiplied by multiplier setting. Dielectric Constant * Capacitance in Aroclor at 100C. Capacitance in air at 100C. Balancing CapaoStance Bridge ? Condensed prooedur. Operator should read operating Instrue- tlon for Mull Detector for complete details. _ 1. Connect to power supply leads to oscillator and null Aeteo! tear. Ground the osoiliator. i 2. Turn on oscillator by pushing 5000 ohm, 10 multiplier, 100 ' oycly frequency buttcam. Adjust harmonic control until oscillation begins as shown by closing of sector in cathode ray tube. j DS\N 331120 J i1 - STLCOPCB4077764 Pagd #2 DIRECTIONS FOR TEST NO sub ject; Dielectric Constant of Liquid Aroolor - Test 14-^6-41 METHOD: 3. On null detector turn brilliance knob to extreme left, the focue knob to extreme right, gain oontrol to extreme left, sweep amplitude at aid-scale position, the sweep frequency switch on line Ida* ;-:K. Vl"v ... 4. Turn an power switch, lighting pilot light. .- . . | 5. Walt fifteen seconds, turn brilliance knob to extreme right. I 6. Adjust focus and brilliance knobs until sharp fine line. I 7, Oonneot external terminals on detector to output terminals on oscillator. Switch sweep frequency to external aide. 6. Connect detector terminals of bridge to input terminals of | detector, taking care that the blade wire (ground wire) a? the lead j goes to grounded terminal cm both ends of lead. ;| - - 9; Set gain control at Bid-scale and selectivity to extreme left. Turn sweep amplitude to extreme left, obtaining vertical, line. With | 10. With turning oontrol knob obtain the maximum length of this line, keeping it vlv&ya under X/k inch with gain knob. I 11. Set eveep amplitude to extreme left. ! 12. Set gain control to give vertical straight line of about 3/8 | inch. j 13. Balance bridge by adjusting power faotor end capacitance dials until only a dot remains on the screen when the gain control le at extreme right. ih. Set sweep amplitude beyond aid-point, and slightly displace the power-factor dial to obtain m tilted ellpse. 15. Adjust phase control until this ellipse closes Into a straight i line Inclined to the horizontal. i16. Bring power-factor dial back to balance position, which should restore the horizontal straight line. Displaoe this oontrol the same amount In the opposite direction. This should again tilt the straight line but In the opposite direction. Adjust phase oontrol until there is no tendency for this line to open up when It Is evung 30 degrees from horizontal In both directions. 17. Throughout these adjustments the other bridge oontrol (the : DSW 331121 STLCOPCB4077765 Page #3. DIRECTIONS FOR TEST NO j subject: Dielectric Constant of Liquid Aroolor - Test lt-36-4l i. | METHOD:_____________________________. capacitance Dial) must be In balance position. If the ellipse graduelly opens whan the line is horlsontal It nay he brought back to the line again by tasking alight changes in this control. If confusion results, balance both controls again as In (13) and repeat the euo\ seeding adJus^nta^/'C. This la the position of bridge balance! An alteration of the poser-factor control will tilt the line which does not open appreoia- | ble thru an angle of 3$ to the hcrliontal both ways; an alteration | of the capacitance dial opens the ellipse but does not change the { inclination of the Major axis. , The apparatus nay ba left in this balanced condition, turned off by switching off first the brilliance knob of the detector, then the | pcsrer switch, then turning off the oscillator. | For successive measurements the controls are not changed, tbs j apparatus left In adjustment. Then the following steps define the I procedure: | 1. Connect all leads as previously directed including that from | null detector to bridge. , S. Turn on oscillator by pushing 100 cycle frequency button. 3 Turn on null detector, wait 15 seconds then turn on cathode i ray tube. Turn sweep amplitude to extreme left and adjust brilliance j to obtain a fine vertical line on screen. k. Bring this line to a dot by adjusting the two bridge controls. Initial adjustment IS facilitated by having ''Gain" control to left. When final adjustment is obtained this knob must be at extreme right. 5. This dot remaining unchanged shows condition of bridge balance. Cleaning Apparatus for Pleleotrlo Constant The oendenser la removed from Aroolar while still hot by suspend ing it from the plate attached to the frame and allowed to drain. Bever | handle condenser by the insulated terminal. After allowing to oool j somewhat a 50-50 mixture of benzene-carbon tetrachloride la poured over I condenser Into the beaker used in the teat. After draining It is washed In a mixture of equal parte benzene-tetrachloride. It is then washed successively in three different mixtures of benzene-tetrachloride, draIn: ing thoroughly between washes. Finally the electrode is placed on clean paper and brought to 100 in oonstant temperature oven. OSNN 2,7>^22 STLCOPCB4077766 ! i Page DIRECTIONS FOR TEST NO.________ SUBJect: Dielectric Constant of Liquid Aroolor - Test 14-36-41 METHOD:__________________________' The beaker la rinsed with the cleaning mixture originally poured, over the condenser, then washed with T.8.P. and hot water. After draining thoroughly It le dried at 100 in the oven. -- When handling the condenser the operator should never suspend it by the terminal to the Insulated platee. WBD-p g/ia/ta FAB:MW Copied 11/3GA3 I i I oS\N 33i^3 STLCOPCB4077767