Figure 82. --View of burned area in stator of unit 1. Damage was believed caused by a 2-inch-diameter discarded cap screw that accidently became lodged in the coil at the factory. 285-616-2281, October 2, 1952.

plans. Other factors relating to scarcity and method of procurement resulted in the contractor procuring wiring, from whatever source that could be found, to substitute for specified wiring. In several cases substitutions were known to be of inferior quality. In one case it was necessary to buy small, high-voltage cable to use for the station-service substation feed until the correct size cable could be delivered.

(b) Station-Service Transformers. --When the station-service transformers were received on the job a number of pieces of insulation and wedges were found floating on the oil of the transformers. The manufacturer's engineer stated that the displacement of the wedges did not impair the transformers, and they were installed as received.

(c) Switchgear. -- The switchgear for the station-service substation and the circuit breakers were good; however, the physical arrangement of wiring and sequence of connections were not in accordance with the drawings. It was necessary to add a number of jumpers, rearrange and reconnect other wires and relocate some equipment before satisfactory operation could be secured. Control fuses were located behind 460-volt busses, making it unsafe to replace them without de-energizing the entire board. They were relocated to accessible positions by field forces.

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(d) Power and Distribution Boards. - Delivery of power distribution boards was late, so completion of the 460-volt connections was delayed until just before the first generator was started. Electrically the control circuits checked out satisfactorily; however, the schematic wiring was not in accordance with the drawings.

The 4, 160-volt power board arrived early but was received in a damaged condition. The damaged parts were sent to Denver for repair. The parts were repaired and returned in adequate time for installation. Wiring and equipment were in excellent condition so no difficulty was experienced in putting the board into service.

The main 460-volt power distribution board and the direct-current board were well designed and of very sturdy construction. No difficulty was experienced in installing the boards or in putting them into service.

The main control board (fig. 83) was well constructed and neat in appearance. This was the most complicated board on the job, but far less circuit trouble was encountered in its installation than in the installation of the more simple boards.

The excitation panels, rheostats, and rototrol voltage regulators were furnished with the generators. The rototrol regulators are extremely sensitive and give very close voltage regulation.

168. Communication Equipment. - A carrier telephone set was installed on the 115-kilovolt Thermopolis line which is cross-connected to the Cody-Casper carrier telephone system. Carrier relaying was installed on the 115-kilovolt Thermopolis and Alcova lines by force account. A sound-insulating wall was installed in the cable spreading room to isolate the carrier equipment and lower the noise level.

A cord-type communication board is provided in the control room at the operator's desk. An outside trunk line into Thermopolis is provided for long distance calls. Extension phones are installed throughout the plant, in the switchyard, at the spillway gate structure, in the office, in the garage and warehouse, and in five residences of the camp.

Short-wave radio station has been installed for local communication with local mobile units, also for communication with more distant points by connections through the radio-relay station located on Boysen Peak.

169. Switchyard Equipment. The switchyard equipment (fig. 84) was installed according to drawings except for slight minor rearrangements necessary to make the delivered equipment fit. The greatest difficulty was encountered through an 8-inch discrepancy in measurements between the selector switches and their fabricated steel bases. This required considerable redrilling and fabrication of steel. After the 34. 5-kilovolt and the 115-kilovolt oil circuit breakers were installed, final adjustments and run charts on the operating cycles were made.

170. Energizing Equipment. - The Alcova-Thermopolis 115-kilovolt line was cut and connected through the switchyard on July 2, 1952, and on July 11, 1952, the 115-kilovolt transformer bank was energized, thereby energizing the No. 1 section of 4, 160-volt bus. The station-service substation was energized next and the 460-volt power board cut over from temporary to permanent power. On July 17, 1952, the 4, 160-volt bus breaker was closed energizing the No. 2 bus, the 34. 5-kilovolt transformer bank, and the 34. 5-kilovolt switchyard. At 6:01 a. m., July 17, 1952, the 34.5kilovolt line to Shoshone, Wyo., was energized initiating the first sale of power through the Boysen switchyard.

171. Difficulties. The completion work for Boysen Dam, Powerplant, and switchyard was slowed from the start by late delivery of materials and drawings. This prevented the proper scheduling of installation work and resulted in an extremely heavy workload for electrical inspectors during the month prior to starting the units, when the more difficult circuit checking was required and experienced electrical inspectors were not available.

CHAPTER XXII--CONCRETE PLACEMENT AND

CONCRETING PROCEDURES

172. Concrete Placement. - Although the dam on this project was an earth and rockfill structure, the quantity of concrete placed in the various tunnel linings, powerplant, spillway, and appurtenant structures made the concrete work one of the major items of construction. Ninety-eight percent of the concrete was manufactured and placed under the prime contract, specifications No. 1890. The following tabulation gives a summary of the specifications under which concrete was manufactured and placed and a summary of the quantity of concrete placed under each of them:

The yardages in the above tabluation are summaries of the concrete quantities paid for under the items for payment in the various specifications. The actual yardages of concrete manufactured, as calculated from the batch yield computations, were slightly higher than the pay quantities in all cases.

(a) Placements Under Prime Contract. --The concrete work under specifications No. 1890 consisted of placing the reinforced concrete in the following structures: powerplant, spillway, outlet works, diversion works, cutoff wall in the earth dam, retaining walls, training wall, fan houses for the relocated railroad tunnel, lining for the relocated railroad tunnel, and bridge piers, abutments, culverts and precast piling for the relocated railroad.

The first concrete placed by the prime contractor was placed on June 19, 1948, in one of the bridge piers for the bridge at mile post 311 on the relocation of the Chicago, Burlington and Quincy Railroad. The last concrete placed was on January 19, 1952, and was in the bonded concrete floor finish in the power plant.

Total concrete placed under specifications No. 1890, as computed from pay quantities, was 147, 792.6 cubic yards. Breakdown of this total into the quantity of concrete placed in each structure is given in the following tabulation:

All of the concrete placed under these specifications, except the concrete in the culverts and precast piling for the railroad relocation, was manufactured and placed by the prime contractor. The concrete in the culverts and precast piling was manufactured and placed by a subcontractor.

173. Plant and Equipment. - All concrete placed by the prime contractor was manufactured in his central batching and mixing plant. The equipment in this plant included, among other things, one 350-ton concrete batching plant; one 4-cubic-yard tilting concrete mixer; one 500-barrel cement silo; one 120-cubic-foot cement conveyor; one cement recorder; one oil-fired boiler; one 66-horsepower boiler; and one vibrating screen, with the top deck of 1-3/4-inch screen and the bottom deck one-half 7/8-inch screen and one-half slotted sand screen.

On April 1, 1949, the batching and mixing plant was destroyed by fire. The 500-barrel cement silo and aggregate conveyor belt trestle were not injured by the fire. The batching and mixing equipment, which was damaged beyond repair, was replaced with the same type and make of equipment as was originally installed. On May 5, 1949, the reconstruction of the building and installation of equipment was completed and concrete was manufactured that same day.

A crew of four men was used during normal operations of the batching and mixing plant. One man operated the batching and mixing equipment; one man operated the concrete receiving hopper; ore man operated the finish screens and aggregate conveyor belt; and one man was at the aggregate storage bins to operate the feeders.