INNOVATIVE METHODOLOGY FOR CARRY OUT LOAD TEST OF ELECTRO MECHANISM EPV-250T USING EQUIVALENT ELECTRICAL LOAD.

摘要

Innovative methodology for carry out load test of Electro Mechanism EPV-250T using equivalent electrical load Electro-mechanism EPV-250T provides the automated electrical drive for opening and closing of fuel shut-off valves A and B used on aircraft. Fuel Shut- off valves A and B are used to control the flow of fuel through pipelines. Both shut-off valves A and B consist of two major assembly viz.mechanical valve assembly and an electro-mechanism EPV-250T. A & B Fuel Shut-off valves quantity per aircraft is 4 & 3 respectively. Electro-mechanism EPV-250T works on 27 volt DC power supply, it consist of: (i) Micro switch assembly: It consists of two micro switches which serve following two purposes: (a) Indicate the position of valve when in fully open / close condition (b) Disconnect the input supply to DC motor of electro mechanism when the valve flaps reach the extreme position i.e. fully open/ close condition . (ii) D-13TF DC motor: It isDC motor which runs in clockwise and anticlockwise direction based on the direction of current with clutch mechanism. It works on 27V DC power supply fed from aircraft systems. (ii) Gear assembly: It consist of 3 set of gear train which convert high speed low torque to desired low speed high torque at output shaft of Electro-mechanism. Electro-mechanism Overhaul procedure was not provided by the OEM to overcome the deficiency new Innovative methodology carry out load test of Electro Mechanism EPV-250T using equivalent electrical load was developed. a) Check the insulation resistance between electrical connector pins and body of Electro Mechanism EPV-250T. It should not be less than 20 Mega ohm, it help to ascertain the condition of electrical insulation of EPV-250T. b) Test stand is modified to carryout load test of Electro Mechanism EPV-250T, carry out initial setting of test stand to meet load requirement (i.e 1-4 kg f/m). c) Connect the electro mechanism to test panel, operate it on 27V DC and check the turn angle of output shaft, it should be from 0 for closed shut-off valves and 90+5 deg for open shut-off valves, an additional pointer assembly is installed to check the position of shut-off valves, Figure 1. Test Set up for testing EPV-250T. d) Load test of electro mechanism, Operate the electro mechanism at operating voltage 27V DC with counter acting load of 2.5 kgf/m. In both the directions for three cycles and check the following during third cycle (Before test open the cover of electric motor) i) Current consumption should not be more than 2.0 Amps. ii) Time taken for rotation of output shaft should not be more than 4 seconds. If it is found satisfactory in the test it is allowed to install on fuel shut-off valves A and B used onSu-30MKI aircraft.