1 Subject content and application scope
This standard specifies the technical requirements, calibration, test run procedures, data acquisition and processing methods of the steady-state speed measuring system for missile used turbojet and turbofan engines during ground test.
This standard is applicable to the steady-state speed measurement of missile used turbojet and turbofan engines (hereinafter referred to as engines) on ground test bench and high altitude test bench.
2 Technical requirements
2.1 Composition of speed measuring system
The block diagram for speed measuring system is shown in Figure 1.
2.1.1 Speed sensor
The speed sensor shall be electromagnetic or of other types and shall be installed on the engine. In the test, the frequency signal fx output by the speed sensor is proportional to the measured speed, thus the engine speed is measured. The equation thereof is as follows:
fx=k·n (1)
Where,
fx——the frequency signal, Hz;
k——the proportionality coefficient, Hz/(r/min);
n——the speed, r/min.
The output impedance of the speed sensor is not greater than 1kΩ, and the output voltage is not less than 5V. The speed sensor shall be verified by the metrological department and be provided with the verification certificate.
2.1.2 Tachometer
The tachometer shall match the output impedance, voltage and measuring frequency of the speed sensor equipped with each engine.
The tachometer, with an accuracy not less than 0.05%, is provided with two outputs, one for data acquisition, and the other for digital display.
1 Subject content and application scope
2 Technical requirements
3 Calibration
4 Test run procedures
5 Test run data acquisition and processing
Additional explanation
