Page 248 - Water Standards
P. 248

6) Operate the guide vane servomotor manually to check the opening limit. Check the
                   indicated value of the indicator on mechanical cabinet and the value shall be in
                   accordance with the stroke of the guide vane servomotor and paddle servomotor.
                   The deviation from the former shall be no larger than 1% of the piston  s whole
                   stroke, while the deviation from the latter shall be no larger than 0   5°.
                 7) The deviation between the guide vane and runner emergency closing time and o⁃
                   pening time, guide vane sequence closing stroke, sequence closing time and
                   their design value shall be no larger than ±5% of the design value. Finally, the
                   deviation shall be adjusted to meet the regulating calculation requirements. Gener⁃
                   ally, the closing and opening times should be twice the time required for an open⁃
                   ing between 25% and 75%.
                 8) The deviation the guide vane closing time of the emergency distribution valve shall
                   be within ±5% of the design value. Finally, the deviation shall be adjusted to
                   meet the regulating calculation requirements.
                 9) Check the reciprocating mechanism dead stroke and the value shall be no larger
                   than 0   2% of the servomotor whole stroke.
                 10) From the opening and closing directions, plot the relationship curve between the
                   servomotor stroke and the guide vane openings. Measure the opening value of 4
                   to 8 guide vanes at each point and average these values. When the guide vanes
                   are totally opened, the opening values of all guide vanes shall be measured. The
                   deviation should be no larger than ±2% of the design value.
                 11) From the opening and closing directions, plot the curve showing the relationship
                   between the guide vane  s servomotor stroke and the runner servomotor stroke
                   under the combinated relationship of different water heads, and deduce the rules
                   determining the opening and closing. The curve and rules shall meet the design
                   requirements. The inaccuracy of the runner and guide vane servo system shall be
                   less than 1   5% of the whole stroke.
                 12) The setting of the servo system  s practical open loop gain. The servomotor
                    opening and closing times shall have been adjusted and meet the design require⁃
                    ments. Set the amplification coefficient and lever ratio to the maximum value in
                    design, and then input a step signal which amounts to 10% of servomotor whole
                    stroke into the servo system. Watch the servomotor movement. The maximum
                    amplification coefficient and lever ratio which can keep the servo system steady
                    and avoid overshoots is the practical open loop gain.
                 13) Record the static characteristic curve of the speed governing system when the per⁃
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