CV2/S41-4(Y8) Nst San Pedro, California. Jan 27 1930 From: Commanding Officer. To  : The Chief of the Bureau of Engineering. Via : (1) Commander Aircraft Squadrons, BATTLE FLEET. (2) Commander in Chief, BATTLE FLEET.   SUBJECT: Results of Examination of "D" Unit Following 30 Day's Use at Tacoma. Reference: (a) C.O. LEXINGTON ltr. CV2/S41-1(Y8) of 23 Dec.1929. (b) C.O. LEXINGTON ltr. CV2/S62-2(Y8) of 27 Dec.1929, paragraph 5.      1.     An examination of "D" turbine following 20 day's service as detailed in reference {a} and reference (b) showed no major defects. The shrouding and tenons were examined from the exhaust trunt and inspection plates and as far as could be seen were in excellent condition. Reference (b) noted the fact that "D" turbine was operated at 1800 R.P.M., 45 R.P.M. above rated speed but no apparent damage resulted from such operation. The turbine operated 442 hours during the 30 days in Tacoma.   F. D BERRIEN - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Copy to Comdt. Navy Yard, Puget Sound.

CV2/S8(Y8) Nst San Pedro, California, Jan 27 1930 From: Commanding Officer. To  : The Chief of the Bureau of Engineering. Via : (1) Commander Aircraft Squadrons, BATTLE FLEET. (2) Commander in Chief, BATTLE FLEET.   SUBJECT: U.S.S. Lexington - Post Repair Trial.   Reference:  (a) C.O. LEXINGTGN ltr. CV2/S8(Y8) of 23 Oct.1929. (b) Bu.Eng. despatch 7919-1634 of November, 1929. (c) Comairons despatch O020-1025 of November, 1929. (d) C.O. LEXINGTGN ltr. CV2/A5-7(Y8) of 22 Jan.1930. (e) C.O. LEXINGTON ltr. CV2/S41-4(Y8) of 27 Jan.1930.      1.    In compliance with references (b) and (c) the post repair trials requested in reference (a) were held on 19 January, 1930. The trial started at 1030 and was completed by 1530. The highest average power developed, at 257 R.P.M., was 149,750 H.P. The maximum current drawn by the main motors was slightly below the limit given on the name plate of the generators. Foul bottom data obtained during the trial has been forwarded to the Bureau by reference (d).      2.    An examination of the machinery at the end of the trials shows no major defects. The shrouding and tenons of the main turbines were inspected and showed no unusual conditions. A slight leak between the H.P. and L.P. casing of "D" unit, however, developed at high power.   F. D. BERRIEN - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Copy to Comdt. Thirteenth Naval District.

Puget Sound Navy Yard I1-25-29 2500   ROUTE SLIP 22 January 1930. JVK:LB From: Staff Headquarters, 13th Naval District, Room 7, Pier l, Seattle, Washington,   To: Commandant.   Via:   Subject: USS LEXINGTON - Kilowatt hours delivered to Tacoma 17 December 1929 to 16 January 1930, inc.   Reference:   Enclosure: (A) Copy of C.O. USS LEXINGTON letter CV2/A9-8(Y8) of 20 Jan. 1930.   For following action:   Forwarded for information and files.         J. V. Klemann. ---------------------------------------------------------------------- Returned, following action taken:

CV2/A9-8 (Y8) UNITED STATES FLEET AIRCRAFT SQUADRONS, BATTLE FLEET U. S. S. LEXINGTON   San Francisco, Calif., JAN 20 1930 From: Commanding Officer. To: Commandant, 13th Naval District.   Subject: U.S.S. LEXINGTON - Kilowatt hours delivered to Tacoma 17 December, 1929, to 16 January, 1930,inc.   Reference:  (a) Comdt. N.Y.P.S. ltr. L11-8/Tacoma, Wash. of 17 Dec. 1929.      l.   The power delivered to Tacoma, listed herein by dates, is a confirmation of the amounts reported daily by despatch: 17  December    7000 2 January 85600 18   " 76660 3    " 122200 19   " 96900 4    " 76000 20   " 106600 6    " 142400 21   " 85400 7    " 161600 23   " 97400 8    " 227800 24   " 61400 9    " 228400 26   " 143400 10    " 286200 27   " 169600 11    " 285600 28   " 182400 12    " 133400 30   " 122800 13    " 295400 31   " 101200 14    " 318200 15    " 330000 16    " 307400 Kilowatt hours delivered to the City from 17 December to 31 December, 1929, inclusive - - - - - - - - - - - -1,250,760 Kilowatt hours delivered to the City from 1 January to 16 January, 1930, inclusive - - - - - - - - - - - -3,000,200 Total kilowatt hours delivered to the City - - - -4,250,960.   F.D. BERRIEN - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Puget Sound Navy Yard 11-25-29 2500 CV2/N7 Power ROUTE SLIP 30 December 1929 JVK:LB From: Staff Headquarters, 13th Naval District, Room 7, Pier 1, Seattle, Washington, To: Commandant. Via: Subject: USS LEXINGTON - Method of connecting ship's power to that of the City of Tacoma. Reference: Enclosure: (A) C.O. USS LEXINGTON letter CV2/S62-2 (YS) of 27 Dec. 1929 with enclosures (10 photographs). For following action: Forwarded for information and return.     J. V. Klemann. ___________________________________________________________________ Returned, following action taken: L11-8 City of Tacoma, LEXINGTON Power (M) PL-Ge-1 1st Endorsement Navy Yard, Puget Sound, Washington FROM: Commandant TO: Staff Headquarters, 13th Naval District, Room 7, Pier 1, Seattle, Washington. SUBJECT:   Method of connecting ship's power to that of the City of Tacoma 1. Returned, contents noted.     - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - H. J. Ziegemeier

CV2/S62-2(Y8) HLW:T Tacoma, Washington, From: Commanding Officer. To  : The Chief of the Bureau of Engineering. Via : (1) Commander Aircraft Squadrons, BATTLE FLEET, (2) Commander in Chief, BATTLE FLEET. SUBJECT: Method of connecting ship's power to that of the City of Tacoma, Enelosure: (A) Photographs, ten (10) views.      1.    The City of Tacoma in five days constructed about two miles of high tension lines across the city to Baker Dock where the LEXINGTON moored. About two days were required to complete the connections from the dock to the ship. In making the connections to the ship, the 22-pole leads were disconnected at No. 4 after main motor, and connected to three copper bus bars, mounted vertically on insulators secured to wooden beams. The shore cables were connected at the upper end of the bus bars and were led to two 1200-ampere circuit-breakers on the dock, which in turn were connected to two sets of three single-phase transformers. Each bank of transformers was connected for "Y" or star hook-up on the low tension (ship's) side and delta on the high tension, 50,000 volt, side. This arrangement will permit use of any one of the four main generators.      2.    The shore leads consist of twelve 750,000 circular mill cables insulated with varnished cambric and asbestos for 5,000 volt service. The banks of transformers have a combined rating of 20,000 K.V.A.      3.    An auxiliary circuit, 125 volts D.C. with pull switches in the control room wam installed to operate the cirouit-breakers on the dock. Synchronizing lights, a synchroscope, and voltmeters were installed in the control room for paralleling the ship's power with that of the city. A kilowatt hour meter, a recording kilowatt meter and an indicating and recording frequency meter also were furnished. Direct telephone connections were made to the despatcher in one of the sub-stations for controlling the amount of power delivered.      4.    Current transformers were mounted on the bus bars in No. 4 motor room and connected to relays in the control room for each phase, to open the circuit-breakers in case of overload. A   -1-

-2- CV2/S62-2(Y8) HLW:T SUBJECT: Method of connecting ship's power to that of the City of Tacoma. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - futher safety feature was installed, to open the circuit-breakers when the generator field was opened by routine operation, ground relays or unbalanced relays, by placing auxiliary contactors on the field switch operating mechanism in a circuit to a relay. The casings of the transformers also were grounded to the ship to operate the ground relay in case of a ground in any of the transformers.      5.    The main turbine, in order to maintain the frequency of the city, 60 cycles, must run at 1800 r.p.m. which is 45 r.p.m. above the rating. Other operating data are: voltage, 4500; power factor, 70 to 100 percent with leading current; load to date, 2000 to 13,000 kilowatts; generator temperatures, below scales of instruments; and frequency variations, less than that of the city. The turbine has been run on the governor to take a fluctuating load while the city plants have taken a constant load. No troubles have been encountered in paralleling or in other operations.     F.D. BERRIEN - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Copy to: Chief of Naval Operations Commander in Chief, UNITED STATES FLEET Commandant Thirteenth Naval District U.S.S. SARATOGA

Enclosed Photos

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