Gage response (relay response) to a rising water surface is prac- 

 tically instantaneous. Gage response to a falling water surface is 

 directly affected by the water salinity and cleanness of the epoxy gage 

 sections. The epoxy gage sections should be kept as free of sea growth 

 and dirt as local conditions will permit. Visual observations of wave 

 action (counting the number of gage contacts from wave crest to trough) 

 on the staff and comparison with the recorded wave record should provide 

 evidence of proper gage operation. If local conditions permit, cleaning 

 the epoxy gage sections and applying a coat of silicone wax to the epoxy 

 will provide outstanding gage response. (Do not coat the copper contacts.) 



In addition to the relay-operating circuit, the gage contains the 

 step-resistance recorder circuit which provides the signal to the recorder 

 as dictated by the number of relays activated by the water level. 



The circuit in Figure 27 shows that when all relays are in the un- 

 energized condition (no gage contacts submerged) , the step-resistance 

 circuit is open and no voltage is available to the recorder input. When 

 the bottom gage-contact is submerged and relay No. 125 operates, all re- 

 sistors in the step-resistance network are in series with the d.c. power 

 and recorder input. As each gage contact is submerged and the relays 

 are operated, the resistors are short-circuited. This provides a higher 

 voltage to the recorder as each relay closes (voltage to recorder is 

 higher as the gage is submerged). Thus, the recorder will follow the 

 change in water submergence of the wave staff. 



2. Fabrication of a Relay-Operated Step-Resistance Gage 



Fabricate the required number of 5-foot gage sections as required 

 for the wave station. Table VII is a parts list for a relay-operated gage. 

 Fabrication details of the sections are shown in Figure 28. Resistor 

 values and cable color-code are in Table VIII. Cable lengths for the 

 sections should be selected for the shortest length practicable to reach 

 the location of the relay cabinet. Cost of the 25-conductor cable used 

 in the fabrication of the epoxy sections is about $0.50 per foot, thus, a 

 five-section gage will have a cable cost of $2.50 per foot between the gage 

 mount and the relay cabinet. 



Fabricate the relay panels and relay power supply according to 

 Figures 29 and 30, and wire them as shown in Figures 31 and 32. Mount 

 these units in the relay cabinet as shown in Figure 33. 



Modify the strip-chart recorder paper speed (if desired) as outlined 

 on pages 



Install three female 115-volt receptacles, one toggle switch and a 

 line cord in Tork Timer Model 4100 as outlined on Figure 10. 



Fabricate a metal gage holder of proper length as shown on Figure 14. 

 Fabricate gage-holder mounting brackets as local installation requirements 



Text resumes on page 59 



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