Document n9V9MBdBrmpZ0wawXBR4q9omX

HOW CAN WE CHECK CURRENT-TRANSFORMER SECONDARIES? Although wk nixioiwcauy check the evercurrent relay* on U our plant Feeder*, we never gave eerlooi thought to tbo rein current tranifortner*. Alter tbe relay* failed to operate oo recent coble foult, we mode i quick check ond loaad them OK, hnt two of the currenMromfortncr lecondarle* were charted.. Wo folly realised, even though we mode s thorough check on oil retoy*, it meant nothing if tho et wot thorted. That started a tyilemule check on ull eurrent iroarformOi Uiing o series test lamp from a 126-v aource, we ipotted ill ct'* with shorted secondary windings. The lest consisted limply f noting the brlghlneaa of the test lamp in series with the mat former secondary. A dhn light showed the winding OK while s bright light Indiested a shorted secondary. Wo know this Is but a rough check since it doesn't tell when only a few lorn* are shorted. The corrert turn ratio Is mighty important since it wilt determine the tripping point o| tbe con nected relays. Wo would appreciate hearing how Pown readers check ct's in their plant*. We hove been thinking of miklsg simple Impedance lest. Woold emmeter and voltmeter readings using o tow voltage oc sottree do the trick?--CA Readers' Answers How Often Should We Resocket Elevator Ropes? rfjl* OaNm ti fttm IdusH lm Wc have been discussing the question of how frequently we should resocket elevator ropes, but are unable to come to any agreement. There seems to be o wide difference of opinion on this sub* jeci even among the experts. One concern, which manufactures and maintains drum elevator machines, re* sockets the car hoisting ropes each year on overhead machines, and every two years on bosement machines- Tbe Bu reau of Standards circulor, "Elevator IFire Rope Maintenance," recommends resocketing all ropes each year on over head machines, and every two years on basement type. It has been our experience that, under normal operating conditions and with proper maintenance, these ropes seldom show signs of fatigue ot the sockets dur ing their life span. We would certainly appreciate tho opinion of Power readers on this ques tion with regard to both the drum and traction type of elevator*.--FAA Recommends Biannual Resocketlng of Ropes Frequency of elevator-rope resocketing is dependent upon ropo wear near the socket and condition of metal in the socket Annual and biannual rasockeilag schedules ere based on conservative estimates of the effective life of metal In the socket. In general, it Is best not to exceed these limits, regardless of tbe condition of rope neor the socket. Rope outside the socket may appear to he as good as new, but trouble may have started within the socket where it can not be seen by casual inspection. As shown In sketch at left, there are several factors that may cauoo trouble within socket. Cracks may occor la socket filler metal and under certain conditions the meutl may be partly pulled out of the socket, or the bood between the metal and rope strands may be broken. Sinco these conditions ar* difficult to detect, frequent rejockelinl is the easiest woy to prevent them. Resocketlng is an inexpensive an^ affective woy of providing safe connec tions (or all types of elevator ropesFAA will find that the odded safety and peace of mind provided by frequent resocketlng is well worth tbe costHence, resocketlng should always be done annually or biannually according to the typo of elevator. Tyier C Hicks New York, N. Y. (Continued on page 140) 1U (796) POWER Doesmbe' AMBRAIOT 927 OOlNO IN At MWARfN. ThvM photo* show hibvi beUg tndolled In part of roitor Wheel** Cron Flow 00.000 iq. (t. <oodoMp-"Qoo ol thm going into tho oow Seworen, N. J. plod* of Rvblic Service floctrlc ond Oat Company. Soli coating wator will bo pumped from tho At. tbvr Kill botwoon Raritan end Newark Boy*. Cadi of tbo throe boiler* It rated at 600.000 pound* of doom per boor at contlovov* op eration] ond ot 990,000 pound* for four Loot poeV toads. Bno p***! t* 1900 . powndt per tq. In. ot turbine throttle, doom temperature 1090* 7. Plant'* Inltlol gsnrating capacity win bo 900.000 kw. Public Service of New Jersey installs Ambraloy 927 ...the tubes "that protect themselves" contact with sea water, Ambraloy are invited to consult our Tbchnica! Depart r927. Condenser Tubes rapidly form a ment in determining the most suitable alloys strong, continuous-surface film of aluminum for specific heat exchange requirements. For oxide. It is this protective coating that gives general information on Anaconda Condenser Ambraloy 927 TVtbes their remarkable re and Heat Exchanger T\ibes and Tube Sheets, sistance to the corrosiveMimpingement"attack send for Publication B-2. *** of aerated sea water flowing at a relatively high velocity. Ambraloy 927 Condenser TUbes (alumi idA num brass alloy) are establishing noteworthy economy records aboard high speed ocean C&UlCaMCz liners and in heavy duty steam turbines oshore--especially at some of the larger cen CONDENSER TUBES & SHEETS tral power stations where sea water, including THE AMERICAN BRASS COMPANY polluted harbor water, is used for cooling. Oanoral Office*: Watarbury 88, Connecticut Engineers and equipment manufacturers Subtidlary ot Anaconda Copper Mining Company In Ciitdu Anaconda Amuiuk 8*ac Lto. /Vow Tbronro, Ont. ['owe * Oecambar 1948