T8821WAC Tachsyn Transducer

The Model T8821WAC Tachsyn Transducer from ServoTek Products are unique tachometer/commutators that can be used as brushless dc tachometers or brushless dc motors. They provide a true tachometer signal and full-time analog commutation control. A miniature remote mounted circuit board (CT-4) provides as field excitation for the transducer as well as the required conditioning for the output signal.

  • Linear, low noise tach signal down to zero speed
  • High accuracy commutation as 6-step Hall-equivalent outputs
  • Elevated temperature operation up to 155 degree Celsius
  • Low inertia, passive rotor for high speeds and rapid acceleration

Contact customerRFQ@marshbellofram.com for pricing and ordering information.



 Commutation Outputs
  • Number of pole                    8
  • Number of phases               3
  • Angle “on” each phase       180° ±2°
  • Angle between phases       120° ±2°
  • Output volts                         dc bus
  • Output impedance              1000 ohms

 Tachometer Output
  • Linearity (entire range)        ±0.1%
  • Volts/1000 rpm                     1.7 Vdc ±10%
  • Ripple                                      ±2%
  • Max. output voltage            dc bus-1 Vdc
  • Min. load resistance             10 K ohms
  • Bandwidth to 45° shift        1000Hz (typ)
  • Offset volts                           2 mV
  • Temp. coefficient             -0.05%°C (typ)

 Power Supply
  • Max. current at ±12 Vdc      0.060 A
  • Max. current at ±15 Vdc      0.075 A

Moment Of Inertia
  • ½” Bore                     15.5 x 10-4  oz-in.-sec²