Woodward Large Electric Sonic Valve II, Инструкция по установке и эксплуатации, Страница: 25 / 66

Manual 35076 LESV II
Woodward 23
Chapter 2.
Description
Actuator: Woodward LELA (Large Electrical Linear Actuator)
The LELA and LELA2 actuators consist of:

A brushless dc motor that provides torque

An integral resolver for motor commutation and position feedback to the controller

A feedback device for motor resolver verification

A magnetostrictive feedback sensor for SIL2 position

A high-efficiency ball screw for rotary-to-linear motion conversion
The LELA and LELA2 actuators also contain:

A fail-safe spring designed to extend the actuator if power is removed from the actuator.

A soft-stop spring to dissipate motor rotor inertia during fail-safe shutdown and prevent ball screw
damage

A cam follower to provide opposing torque during slew operations

A lifting eye(s) to aid installation
Brushless DC Motor
The motor assembly used on the LELA2 is a permanent magnet, electrically commutated, brushless dc
motor. The components used in the motor assembly are rated for service from –40 to +155 °C
(–40 to +311 °F).
Resolver Position Feedback Sensors
The primary position feedback transducers are the dual redundant resolvers that are integral to the dc
brushless motor assembly.
The 2” LESV II actuator (LELA) also has a valve stem resolver for secondary position feedback. This
resolver is used as a watchdog function of the primary motor control, to prevent runaway conditions and
to ensure that the primary motor resolver is reading correctly. Linear shaft motion is converted to angular
rotation for the valve stem resolver through a linkage.
The 3”, 4”, and 6” LESV II actuator (LELA2) has a valve stem LVDT to provide secondary feedback.
Parameter files are loaded onto the DVP to specifically match the valve characteristics in order to obtain
the most accurate position sensing.
Optional SIL2 Position Feedback Sensor
The LELA actuator is available with an optional magnetostrictive feedback sensor. The sensor is
connected to the valve stem for a SIL2 light-off flow function.
Electronically, the SIL2 sensor is connected only to the customer control system and is not connected to
the Woodward DVP. The SIL2 sensor serves as a position indicator for valve position that is independent
of the DVP, and is used primarily to accurately control fuel flow during turbine light off.
The components in the SIL2 sensor are rated for service over a range of (–40 to +93) °C / (–40 to +199)
°F. However, to meet the SIL requirements for component reliability, the LESV II ambient temperature
range has been limited to (–29 to +80) °C / (–20 to +176) °F. Therefore, if at any time while the LESV II is
in service, the ambient temperature e80 °C, the sensor must be replaced. Refer to Chapter 4 for
instructions for sensor replacement.
Released