Woodward 2301E-HT, Руководство по эксплуатации продукта

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Manual 35092 2301E-HT Hydro (Francis Turbines)
Woodward 25
from its center position. Typically, the proportional valve ports oil to another valve, or hydraulic amplifier,
which then positions the servomotor.
The integrating signal has three adjustments that must be made. The first adjustment is to configure the
control for a reverse acting valve or a forward acting valve. Most valves will be forward acting, meaning
that an increase in the actuator control current (greater than the null current, 12 mA) results in the gates
opening. If the system is reverse acting, meaning that a decrease in the control current results in the
gates opening, then “Reverse Acting” must be tuned TRUE. The second adjustment is the “Valve Offset.”
The null current will probably never be equal to exactly 12.00 mA, so the valve offset makes up for this
difference. If this is not adjusted properly, the gate position will not match the gate position demand. The
third adjustment that needs to be made to th
e integrating signal is the “Valve Gain.” This controls how
much the current deviates from the null current for a given gate position error. If the gates are sluggish to
step changes, the gain can be adjusted to increase the gate response, or if the gates overshoot during a
step change, the gain can be adjusted to decrease the response.
The 2301E-HT control has a dither function designed into its valve driver output. The valve dither function
induces an ac current on the actuator output. Valve dither accomplishes two things. First, it keeps the
valve plunger(s) constantly moving which reduces “stiction,” or static friction. “Stiction” can cause gate
hunting if the valve does not respond correctly to the electronic signal. Second, dither makes a positive
lap valve respond as though it were a zero lap valve.
The 2301E-HT continuously compares the actual gate position to the gate position demand in the control.
If they do not match within the “Minor Mismatch Window” for more than the “Minor Mismatch Delay” time,
the control will issue a “Minor Mismatch” alarm. If the gate position does not match the demand within the
“Gross Mismatch Window” for more than the “Gross Mismatch Delay” time, the control will issue a “Gross
Mismatch” Shutdown.
Brake Permissive
One of the 2301E-HT relay outputs can be configured to act as a Brake Permissive. If this function is
configured, the relay output will close when five conditions are met:
1.
the control has to receive a “Stop” command
2.
the speed must be below the “Brake Enable Speed”
3.
the gate position must be less than the “Brake Enable Gate Position”
4. the gate position signal must be valid
5. the speed signal must be valid
The relay output opens when the "Brake On Time" has expired. Additionally, the brakes can be
configured to pulse on and off by setting "Pulse On Time" and "Pulse Off Time" under the Brake Service
header.
Due to slight fluctuations in the calibration of gate position transducers, it is recommended that the “Brake
Enable Gate Position” be set slightly above zero percent gate position. The default value is 2%.
Creep
The 2301E-HT can be configured to detect unit creep. Two discrete inputs are required to use this
function. The inputs come from proximity switches focused on the speed gear. One proximity switch must
be centered on a gear tooth, and the other proximity switch must be centered on a gear trough (or in
between two gear teeth). The 2301E-HT will detect a creep as slight as one gear tooth of rotation.
When creep has been configured, the 2301E-HT will start looking for c
reep once the unit is given a “Stop”
command, the speed has decreased below the “Creep Speed,” and the “Dead Stop Time” has expired.
Once a creep is detected, the control will stay in the alarm condition until the “Reset Creep Time” expires.
The 2301E-
HT will look for creep again when the “Look Again Time” has expired.
The creep alarm is sent to the general governor alarms and to Modbus. A configurable relay output can
be configured to energize upon a Creep Detection.
Released