The basic electrical equipment specified consisted of a motor- generator set, a drive motor, and a control panel for the hoist and for the elevator, It was later found, that it would not be necessary to operate the hoist and the elevator at the same time. On this basis, one motor-generator set was omitted, at a saving of approximately $7,500.00 per tower, The capacity of the motor-generator set was made large enough to supply the largest drive motor, and a selector switch located in the building housing the motor-generator set was provided to transfer the controls from the hoist to the elevator or vice versa. This switch was not duplicated in the tower cab, since telephone communication was provided between the tower cab and the building which housed the control cabinet and motor-generator set. In the development of the control scheme for the hoist and elevator, duplicate sets of controls were specified. A control pedestal was required at the hoist and at the elevator cable drums for the control of each unit, In addition, a duplicate set of controls was provided in the house at the top of the tower for both the skip and the main hoist. For the skip hoist, there was a third control in the elevator cab, Limit switches were provided at the top and the bottomof the tower for the elevator and the hoist. These switches were provided to stop either unit automatically, thus providing for emergency stops as well. Other required electrical safety devices included cable limit Switches and an overspeed switch, both located on the cable drum, and a door interlock switch located on the cab door. The cable limit switches were provided to stop the elevator or hoist automatically to prevent overtravel of either unit in the event that the limit switches on the tower failed to operate, The elevator cab door limit switch was provided to prevent travel of the cab when the door was open. After the equipment was fabricated, a test of the first unit was conducted to demonstrate that it would operate satisfactorily. This test was witnessed by a representative of the Sandia Corporation as well as by representatives of the AEC, The entire test was conducted on the ground, using a prony brake to load the drive motor, All conditions of operation were checked, and errors in the control scheme were corrected so that the equipment performed to the complete satisfaction of the AEC representatives who witnessed the test. The remaining units were not tested prior to shipment, but all modifications in the first unit were incorporated in the remainder of the units prior to shipment. The elevator control cable being over 100 feet long, gave considerable trouble because of the high velocity winds blowing it against the structure, This caused chafing and eventual breakdown of the cable. This condition was partially remedied by the installation of a cable guide and counterweight consisting of a guide sheave mounted on a 6 inch aluminum channel, Figure 5.11-5 shows the elevator control cable guide used for 200 foot and 300 foot Towers, Use of this guide, while preventing excessive swaying of the cable, did result in added tension on the cable, This added tension tended to 5-137