We developed a custom solution for 8.H120.355A.2048.0020, for heavy motor and generator systems where 2048 PPR push-pull feedback must stay stable under 25 mm through-shaft mounting, torque-arm movement, 2 m cable routing, and EMC noise.

Model reading:

  • 3 = 100 mm torque arm
  • 5 = 25 mm through hollow shaft
  • 5 = push-pull with inverted signals, 10–30 VDC
  • A = radial PVC cable, special length
  • 2048 = 2048 pulses per revolution
  • 0020 = 2 m cable length

Typical production lead time: 15 working days.

At 2048 PPR, the system usually fails first at counter margin, shield continuity, shaft fit, or torque-arm restraint. The optical sensor is rarely the first weak point.

Where the System Fails First

The 25 mm through hollow shaft must stay concentric. If the shaft fit is loose, A/B phase jitter appears before visible mechanical damage.

The 2 m radial cable is short, so cable length itself is not the main problem. The real risk is routing: if the cable runs close to inverter output or motor power lines, the push-pull edges become noisy before the encoder body fails. Standard push-pull transmission is rated up to 150 m at 80 kHz, but that assumes correct shielding and grounding.

Typical failure points:

  • Loose 25 mm shaft fit → phase jitter
  • Forced 100 mm torque arm → housing oscillation
  • Poor cable shielding → unstable A/B/0 edges
  • Counter margin too low → missed pulses
  • Grounding error → reference signal noise
  • Shaft current without isolation control → feedback damage risk

Mechanical Boundary

H120 provides 2.5 kV bearing isolation, HD-Safety-Lock™, double shaft protection, IP67, seawater-resistant housing, 475 N radial load, 375 N axial load, and -40 °C to +100 °C operation. These margins only help when shaft fit, torque-arm geometry, and shielding are controlled.

Installation Notes

  • Keep the model format as 8.H120.355A.2048.0020
  • Check the 25 mm through hollow shaft fit first
  • Install the 100 mm torque arm without side-loading the housing
  • Route the 2 m cable away from inverter and motor power wiring
  • Keep shielding continuous from encoder to cabinet
  • Confirm counter capacity at real RPM and 2048 PPR
  • Check shaft-current isolation before replacing the encoder

Key Data

  • Model: 8.H120.355A.2048.0020
  • Type: Heavy-duty through hollow shaft incremental encoder
  • Resolution: 2048 PPR
  • Output: Push-pull with inverted signals
  • Supply voltage: 10–30 VDC
  • Max frequency: 300 kHz
  • Max cable length: 150 m at 80 kHz
  • Shaft: 25 mm through hollow shaft
  • Mounting: 100 mm torque arm
  • Connection: 2 m radial PVC cable
  • Protection: IP67
  • Temperature: -40 °C to +100 °C
  • Shaft load: 475 N radial / 375 N axial
  • Shock: 2000 m/s², 6 ms
  • Vibration: 150 m/s², 10–2000 Hz