Click to Zoom
 Download Spec Sheet

QR787 (Blind Bore)

  • Overview
  • Specifications
  • Info & Pricing

About QR787 (Blind Bore)

Quantum Devices, inc. Model QR787 blind bore version provides a high performance, high resolution digital feedback solution for small motor applications. The QR787 model 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, 5 volt RS-422A differential or high voltage differential line driver. QDI’s patented sensing scheme embodies a much simplified encoder design, which ultimately results in longer life and less downtime due to feedback device failure. The encoder housing is constructed of a carbon fiber composite that provides the EMI shielding of an all-metal housing an performance of a lightweight robust assembly.

Design Features:

  • Miniature Size, 20mm (0.787″) diameter
  • Resolutions up to 2048 lines per revolution direct read
  • Blind bore (hollow shaft)
  • 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 80 mA max. output option 01 & 02, 35 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
Bore Diameter (Tolerance) 0.125", 2mm, 2.5mm, 3mm, 4mm (+0.0005/-0.0000")
Shaft Material 360 brass
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

More Information & Pricing

To get more information and pricing about this product, please tell us more about what you are looking for below and we can get you what you need:

Consult factory for configurations not shown (e.g. resolution, commutation, etc.).

Download Spec Sheet

Log In

Forgot Password?

Create an account

Create an account to gain access to all of our 3D models!

Create Account

Create an account to gain access to all of our 3D models!

Forgot Password