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QR787 (Shaft)

  • Overview
  • Specifications
  • Info & Pricing

About QR787 (Shaft)

Quantum Devices, Inc. Model QR787 Is intended for applications requiring high performance, high-resolution digital feedback in a very small package. The model QR787 provides the resolution of larger encoder packages, but in a package only 20mm (0.787″) in diameter. Outputs can be configured in either single ended, open collector or internal pull up resistor, or with an industrial standard RS-422A differential line driver. QDI’s patented sensing scheme embodies a much simplified encoder design, which ultimately results in longer service life and less down time due to feedback device failure. The encoder housing is constructed of a conductive carbon fiber composite that provides the EMI shielding of an all metal housing and performance of a lightweight robust assembly.

Design Features:

  • Miniature Size, 20mm (0.787″) Diameter
  • Resolutions up to 2048 lines per revolution direct read
  • Single ended and differential outputs
  • Long service life
  • Conductive carbon fiber housing
  • IP 50 sealing
  • High noise immunity
  • Low supply current requirements
  • RoHS Construction

Note: prior to transitioning to RoHS-compliant, the product name was QD787 rather than QR787. Therefore, when cross-referencing a QD787 configuration, simply substitute the configuration prefix with QR787.


Electrical Specifications

Input Voltage 5 VDC ±5% or 5-26 VDC
Input Current Requirements 100 mA max. output option 01 & 02, 50 mA max. output option 03; plus interface loads
Input Ripple 2% peak to peak @ 5 VDC
Output Circuits AM26LS31 RS-422A line driver
TTL Output
OL7272 Line Driver
Output Format Quadrature with A leading B for CW Rotation
Ungated Z index pulse true over A and B high
Frequency Response 200 kHz
Symmetry 180 degrees ±10% typical
Minimum Edge Seperation 54 electrical degrees

Environmental Specifications

Storage Temperature -40 to 125°C
Operating Temperature 0 to 70°C typical
-20 to 100°C optional
Humidity 98% Non-condensing
Vibration 20 g's @ 50 to 500 CPS
Shock 50 g's @ 11mS duration

Mechanical Specifications

Maximum Shaft Diameter 8000 RPM
Nominal Shaft Diameter 0.125"
Shaft Material Stainless steel
Bearings Radial ball bearing, R2 type
Radial Shaft Load 2 lbs. maximum
Axial Shaft Load 1 lb. maximum
Housing Carbon fiber composite (case ground via connector)
Housing Volume Resistivity 10⁻² ohm-cm
Termination Two rows of 5 pins on 0.100" centers
8" ten conductor ribbon cable with 2x5 connector
Mounting Servo
Moment of Inertia 9.5x10⁻⁶ oz-in-sec²
Acceleration 1x10⁵ radians per second²
Info & Pricing

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