DC tachometer generators provide a convenient means of converting rotational speed into an isolated analog voltage signal suitable for remote monitoring and velocity control applications. Tachometers are particularly suited in precision integrator and velocity servo applications, both of which require a highly linear speed/voltage relationship with minimum ripple. The nearly pure dc output-with no phase shift-allows tachometers to be used as velocity feedback transducers for fast-response servos and other devices. DC tachometers are also excellent rate generators for velocity damping in low speed position servo applications.
Servo-Tek Tachometer Generators
Servo-Tek Tachometer Generators provide a convenient means of converting rotational speed into an isolated analog voltage signal suitable for remote indication and control applications.
Combining high accuracy with low driving torque, Servo-Tek tach generators are ideal for use in servo systems. Tach Generators are particularly suited to application in precision integrators and velocity servos, both of which require a highly linear speed/voltage relationship with minimum ripple. DC Tachometer Generators are also excellent rate generators for velocity damping in position servos.
The nearly pure dc output-with no phase shift-allows Servo-Tek Tach Generators to be used as feedback transducers for numerous types of equipment, including fast-response servos and other devices.
Servo-Teks’ family of DC Tachometers includes:
- A Series - DC Tachometers with output signal between 1 and 10 volts/1000 rpm.
- B Series - DC Tachometers with output signal between 11 and 24 volts/1000 rpm.
- D Series - DC Tachometers with output signal between 25 and 50 volts/1000 rpm.
- E Series - DC Tachometers with output signal between 0.7 and 3 volts/1000 rpm.
- F Series – Low ripple DC tachometers with output signal between 1 and 8 volts/1000 rpm.
- H Series - Low ripple DC tachometers with output signal between 5 and 16 volts/1000 rpm.
- J Series - Low ripple DC tachometers with output signal between 16 and 30 volts/1000 rpm.
- Sealed Tachometers available with a variety of outputs.
Tach Generator Construction
Servo-Tek Tach Generators are housed in aluminum casings protected in accordance with Mil-C-5541 or Mil-A-8625. Alnico permanent magnets are used. Armature shafts are stainless steel, and rotate on fully-shielded stainless steel ball bearings. Commutators are made from an alloy containing 95% silver. Armature laminations are wound with Isomid insulated wire, over Teflon slot insulation. The entire armature is impregnated and baked, resulting in a NEMA Class H insulation system.
Tachometer Generator brushes and commutators are matched for long life and stability. Operation at 1 mA output will deliver maximum brush life.
Linearity, of Servo-Tek DC Tach Generators, at any speed is better than 0.1% of the output at that rpm.
The DC Tachometer Generator ripple rms value will not exceed 3% of the dc value at any speed in excess of 40 rpm on standard units; 1.5% on low-ripple models.
All Servo-Tek DC Tach Generators operate in either rotational direction. That direction can be determined by output voltage polarity. Output (in either direction) is held to a tolerance of 0.25% of the average output.
Optimum brush and commutator combination gives 0.1% stability. Highly stable output gives no evidence of long-term drift.
Servo-Tek DC Tach Generators are factory tested with an ac potential of 1,250 volts rms applied for one second between (either) terminal and the shaft.
Tachometer Generators are designed for continuous operation in ambient temperatures ranging from -55°C to +100°C(-67°F to +212°F). Voltage output at 25°C will not deviate by more than 0.01% per degree of change within the range of -20°C to +75°C. All Tachs are temperature compensated, with the exception of Series D and E.