We developed a custom solution for 8.H120.4351.1024, for heavy motor and generator systems where 1024 PPR push-pull feedback must remain stable under through-shaft mounting, torque-arm restraint, shaft current risk, and EMC noise.

Model reading:

  • 4 = 150 mm torque arm
  • 3 = 20 mm through hollow shaft
  • 5 = push-pull with inverted signals, 10–30 VDC
  • 1 = radial PVC cable, 1 m
  • 1024 = 1024 pulses per revolution

Typical production lead time: 15 working days.

At 1024 PPR, the counter load is moderate. The first problem usually appears at the mechanical interface, not at the optical sensor. A through hollow shaft must stay concentric; if the torque arm is forced or the shaft fit is loose, the encoder will show phase jitter before the bearing shows obvious damage.

Where the System Fails First

The 20 mm through hollow shaft makes installation flexible, but it also makes shaft fit and torque-arm geometry critical. The torque arm must prevent housing rotation without loading the encoder body sideways.

For standard push-pull output, the datasheet gives 300 kHz maximum pulse frequency and 150 m maximum cable length at 80 kHz. This model uses a 1 m radial cable, so signal length is not the main limitation. The real signal risk is usually shield termination, grounding, inverter noise, or poor cabinet routing.

Typical failure points:

  • Loose through-shaft fit → phase jitter
  • Forced torque arm → housing stress
  • Poor shield grounding → unstable A/B edges
  • Counter filtering mismatch → false counts
  • Shaft current without isolation control → feedback damage risk

Mechanical Boundary

H120 is built for large drives: 2.5 kV bearing isolation, HD-Safety-Lock™, dual shaft protection, IP67, seawater-resistant housing, 475 N radial load, 375 N axial load, and -40 °C to +100 °C operating range. These margins help only when the hollow shaft and torque arm are installed correctly.

Installation Notes

  • Keep the model format as 8.H120.4351.1024
  • Control the 20 mm through hollow shaft fit before checking electronics
  • Install the 150 mm torque arm without side-loading the housing
  • Keep cable shield continuous from encoder to cabinet
  • Separate encoder wiring from inverter and motor power cables
  • Confirm counter settings at real RPM and 1024 PPR
  • Check shaft-current isolation before replacing the encoder

Key Data

  • Model: 8.H120.4351.1024
  • Type: Heavy-duty through hollow shaft incremental encoder
  • Resolution: 1024 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: 20 mm through hollow shaft
  • Mounting: 150 mm torque arm
  • Connection: 1 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