Document zdoaBxNV4yEk1BrRgpjrG8En7

wo \ \ t) I > < *) ) % DIRECTIONS TOR TEST MO. 14-Q&-41 (So/ISftrr i~ SUBJECT* Dielectric Strength of liquid Aroclor MMIHOPt - - ~ -V-- - - ^ : V Scope "v' - ' This wethod applies to mineral oils and oil substitutes used .fear Insulating purposes. .... v ; . ' ,v**4] ' -...; . ' ' Apparatus ' Capacitanae Bridal General Radio Co.( Type 716-AM Oatbods Bay Moll Deteotor * * "yps 7CfHk Oscillator ? * Type 606nd Constant Temperature Ovan Genco-DeKhotinslcy #95050 Variable Air Condenser General Radio 00., Typo 334HF 1300 ee. Pyres Beaker . / Procedure \ 'V Electrode and beaker must be oloaaed as directed under "Clean ing Apparatus Tor Dielectric Constant-, and fee at 100*0. Beat Arcelor in the can to 106*0. Pour over electrode until plates and esramlo Insulation is covered. Connect leads. Stir with thermometer outside oven until temperature reaches 101*; place in Oven which has been carefully adjusted to 100*0. At the time saw- pie is placed in oven its temperature should have fallen below *o*c. , . . . * . >, :/ ; /, v 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 beacne identical the bridge balance will constantly shift. After even temperature reaches 100*0., maintain bridge balance until no pronounced shift is evident. Record reading of capacitance scale ultlpllod by multiplier setting. Dielectric Constant Capacitance In Aroclor at 1QQ*0. Capacitance in air at l00*Q. Balancing Capacitance Bridge Condensed procedure. Operator should read operating Instruc tion for Kail Deteetor for complete details. 1. Connect to power supply leads to oscillator and null detec tor. Ground the oscillator. SW331124 STLCOPCB4077768 I} ) i Page Bo. 8 61 Dieleetrle DUimtof Liquid Aroolor * toot 14r0&-4l ' 8, Torn on oscillator by pushing &OOQ ol, 10 multiplier, 100 cycle frequency buttons. Adjust harwmia oontrol until oscillation begins as shown toy tlosing of sector la cathode ray tubs. 9. Os soil dateotor ton brilliance knob too extras* .left, tohs , foeue knoto too extreme right, gain control to sectored left, swoop amplitude at mid-scale position/the sweep frequency switch on lias VO*. :v 4. fttra on power switch, lighting pilot light. 8. Unit fiftssn seconds, turn toriXlisnos knob too extreme right. 6. Adjust focus and bllllanes knobs until sharp fins lias. 7. Oonneot extarwl terminals on detector to output terminals on oscillator. Switch sweep frequency to external aids. i 6. Oonneot detector terminals of bridge to input terminal# of detector, taking cars that the black wire (ground wire) of the lead goes to grounded terminal on both ends of load. 9. Set gain control at mid-scale and selectivity to extreme left. Turn sweep amplitude to extreme left, obtaining vertical line. With gain oontrol wake thin about 1/4* long. ; - - . *' -/ ` V '- - .......... ' 10.nth tuning control knob obtain the maximum length of this lino, keeping it always under 1/4 inch with gain knob. 21. Sot swoop amplitude to extreme loft. * IS. Set gain control to give vertloal straight lino of about 3/6 lttOh. " . : 13. Balanoe bridge by adjusting power faotor and eapaoitanee dials until only s dot remains on the screen when the gain control ' la at entrant righd.-.a;:- =.. >"- ... :Y:. . /YY/y. - Y^;. VyY T' 14. Set sweep amplitude beyond wid-point, and slightly diaplace the power-factor dial to obtain tlltod ellpea. ' 15. Adjust phase control until this ellipse oloses into a straight line inclined to the horlnoatal. . lfl. Bring ponwr-ftetor dial hack to balanea position, which should restore the horlsontal straight 11ns. Dleplaoe this control the same amount In tbs opposite dlreotion. this should again tilt the straight DSW 331125 STLCOPCB4077769 I fWa..3 ~~ Dielectric Sttsagth of Liquid Aroolor -- Toot 14-G5-41 ' lino but in tbs opposite direction. Adjust phase control until there It no tendency for this line to open up when It ie swung 30 degrees from horizontal In both directions. ' 17. Throughout these adjuetawntsihe other bridge oontrol (the cepasitenoe dial) sunt be ia balance position* If the ellipse grad- uelly opens when the line ie horizontal it say be brought book to the line again by asking alight obangee in thle control. If confusion results, balance both controls egaln as in (13) end repeat the sue- oeedlng .adjustments. thie is the position of bridge balance! An alteration of the power-faotor control id 11 tilt the line which docs not open appreoieI ble thru en angle of 30* to the horizontal both waysj an alteration i of the oapaoitanoe dial opens the ellipse but does not change the inclination of the major axis. Tbs apparatus may be left in this balanced condition, turned off i I by switching off first the brilliance knob of the detector, then the i poorer switch, then turning off the oscillator. ;; For successive measurements the controls are not changed, the apparatus left in adjustment. Then the following steps define the procedure* 1. Conneot ell leads as previously directed including that from hull detector to bridge. . . S. TUrn on oscillator by pushing 100 cycle frequency button. . *. . i 8. Turn on null detector, wait 15 eeoonde then turn on cathode ' ray tube* Turn sweep amplitude to extreme left and adjust brilliance to obtain a fine vertical lino on screen. `-V-, .. . . - . .. V -_ 4. Bring thle line to a dot by adjusting tbe two bridge controls. Initial adjustment is facilitated by haring "Gain* control to left. ^ /_ Shea final adjustment le obtained this knob suet be at extreme right. c 5. Thls dot remaining unchanged shows oondltion of bridge balance. r? Cleaning Apparatus for Dielectric Constant ' 1 The condenser is reaovod fro Aroolor While still hot by suepend- log it from the plate attached to the frame and allowed to drain. Sever handle condenser by the insulated terminal. After allowing to cool somewhat a 50-60 mixture of bonrene--carbon tetraohloride le poured over | oondeneer into the beaker used in the test. After draining it is washed j; in a mixture of equal parts benzene-tetrachloride. It le then washed ;i successively In three different mixtures of benzene-tetraohlorde, dr&lni! Ing thoroughly between washes. Finally the electrode is pL&oed on clean paper and brougit to 100* in constant temperature oven. DSW 331126 STLCOPCB4077770 ) Bags Mo. 4 ` Dleleotrio ^BtSShgth of Liquid Aroolor -- foet 14-GS-41 fit* beafcsr Is rinsed with the eleanlng alxture originally poured over the condenser, then sashed with f.S.P. end hot water. After draining thoroughly it la dried at .100* la the oven. When handling the oondenaer the operator should never suepend It hr the teraibal to the Insulated platos. WBD-p 2/12/48 ///?// ^ - ' "- ' ? !i ! . .\ ii:j DSM\I*^7 STLCOPCB4077771