Is a DC operated non-contacting rotary position transducer

About the R30D RVDT

The R30D RVDT (Rotary Variable Differential Transformer) is a DC operated non-contacting rotary position transducer. Integrated signal conditioning enables the R30D to operate from a bipolar ±15 VDC supply, and provide a high level DC output that is proportional to the full angular sensing range of the device. Calibrated for operation over ±30 degrees, the R30D provides a +/-3.75VDC output, with a non-linearity of less than ±0.25% of full range. Extended range operation up to a maximum of ±60 degrees is possible with increased non-linearity.

Internally, the DC supply voltage is converted into an AC carrier signal which excites the primary coil of the sensor. An integrated demodulator amplifier with low-pass filter converts the differential secondary output into a smooth, high level, linear DC output signal relative to the angular position of the shaft.

High reliability and performance are achieved through the use of a specially shaped rotor and wound coil that together simulates the linear displacement of a Linear Variable Differential Transformer (LVDT). Non-contact electromagnetic coupling of the rotor provides infinite resolution thus enabling absolute measurements to a fraction of a degree.

The R30D features a rugged aluminum size 11 housing making this rotary position sensor ideal for applications where integrated signal conditioning and small size are required.
Also see our other angular position sensor models, R60D (±60°, bipolar DC operation), RVIT-15 Series (single ended DC operation, voltage or current output), R120LC (+5VDC operation, low cost) and R30A/R36AS (AC operation).

Features R30D

  • Extended operation up to ±60°
  • High level, low noise DC output
  • Long term reliability
  • Excellent temp. performance
  • Rugged anodized aluminum housing
  • Shielded ABEC 3 precision bearings

Applications for R30D

  • Hydraulic pump control
  • Throttle lever position feedback
  • Rotary actuator feedback
  • Dancer arm position
  • Reeler/Dereeler
  • Valve position


Angular range, degrees
±30º (standard), ±40º, ±60º
Output at range ends
±3.75VDC, ±5.00VDC, ±7.50VDC
0.125 V/degree
Temp coefficient of sensitivity
0.04%/ºF [0.07%/ºC], over operating temp. range
Input voltage
+/-15VDC ±10%
Input current
25mA maximum
Output current
Output impedance
1 O maximum
Frequency response
500Hz @ -3dB
Storage temp.
-67°F to +257°F [-55°C to 125°C]
Mechanical angular range
360 degrees (no stops)
Shielded ABEC 3 precision
Housing material
Aluminium, anodized
Size 11 servo mount BU-ORD
Moment of inertia
0.53 x 10-6 inch.lb-force.second2 [0.61 x 10-6 Kg-force.cm.second2]
Maximum torque, unbalance
0.004 inch.ounce-force [0.3 gram-force.cm]
Maximum torque, friction
0.015 inch.ounce-force [1.1 gram-force.cm]
Shaft load capability
10 lb [4.5Kg] Axial; 8 lb [3.6 Kg] Radial
Electrical connection
4 lead wires, 28AWG , PTFE insulation, 12 inches [30cm] long
1.9 oz [54 grams]
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