10
T32FNA
6
Supply voltage
for rotor
7
15kHz, 54V/74V
1
2
--15V
3
+15V
4
”MD”-output signal
5/15kHz
. . . . .
4
Speed signal 25 V
1
7
Speed signal 25 V
Rotor
Stator
Pre--amplifier
”MD” and ”n”
Plug ”MD”
Plug ”n”
Fig. 2.2:
Schematic circuit diagram
2.1.2 Speed measurement system
The rotor carries a toothed wheel with 15 teeth for the determination of speed.
On the stator there are evenly distributed, four inductive pick-ups. During one
revolution of the rotor 15 voltage pulses are produced the frequency of which
is proportional to speed. The pick-ups are displaced in such a way that two
pulse trains appear with a phase shift of 90
. The phase shift serves as the in-
formation on the sense of rotation of the shaft.
A pre-amplifier serves to transform the two pulse trains into square waves of
25V peak-to-peak. The speed proportional square wave is available at the ”n”
plug for further processing.
Experience has shown that smooth, vibration-free running and a concentric
rotor are essential for accurate measurement of speed.
Vibration is permitted up to a maximum vibration amplitude falling with in-
creasing speed (see Fig. 2.3, Curve A).
If there is static eccentricity of the stator to the rotor, the possible maximum
vibration amplitude displacement (relative vibration displacement is reduced.
Curves B, C and D are examples of this relationship for eccentricities of
0.5 mm, 1 mm and 2 mm.
SUNSTAR传感与控制 http://www.sensor-ic.com/ TEL:0755-83376549 FAX:0755-83376182 E-MAIL:[email protected]
SUNSTAR自动化 http://www.sensor-ic.com/ TEL: 0755-83376489 FAX:0755-83376182 E-MAIL:[email protected]