Avtron M3 Large-Bore Encoders (M3-6/9, M3-G/J)

Avtron M3 Large-Bore Encoders (M3-6/9, M3-G/J)

The Most Durable Optical Large-Bore Encoder Available!

  • Mill Duty
  • Wide-Gap Technology: Up to 8X larger gap between sensor and rotor
  • Up to 2500 PPR
  • No couplings required
  • Heavy duty bearings and seals
  • Rugged cast housing
  • Dust and liquid tight
  • Available in thru shaft and end of shaft models
  • Fits large motor and load shafts directly
Outline Drawing

Avtron M3 large bore hollow shaft mill duty optical hollow shaft encoders fit motor or load shaft from 1 1/2" to 2 3/8" [48mm-60mm].
Looking for solid shaft M3-1 and M3-2 models or small-bore M3 models?  Use our cross reference page to replace these models with the latest Avtron models.

Forget tiny hollow shaft encoders that require shaft reduction and special protection! M3 mill duty encoders can accommodate up to a 2 3/8" shaft directly and are designed for use in rougher applications than ordinary optical encoders.
M3 has bigger bearings than light duty and commercial grade encoders to withstand more shaft vibration and stress. M3 encoders are designed with bigger, heavy-duty seals to keep contamination out of the encoder and keep your machines working.
M3 encoders offer a large variety of connector and mounting options to replace virtually any existing encoder or tachometer. When you install an Avtron M3, you’ve upgraded to the most durable optical encoder available anywhere!

Also available:  Heavy mill duty HS45 and severe duty AV685 encoders.
Operating Power: 5-24 VDC, 5-18V, 12-24V; Current 120mA, no load
Output Format: A,/A, B,/B, C,/C ; Marker Z,/Z 
Frequency Range: 0 to 150 KHz
PPR: 240-2500
     5000 RPM Max. Std., shafts 1 1/2" to 1 5/8" 
     3600 RPM Max. Std., shafts 2" to 2 3/8" 
     (for higher speeds, consult factory)
Temperature: -40°* to 85°C (*-20° standard)
Chemical: Polyurethane enamel paint protects against salt spray, mild acids, and bases
Weight: 7 lbs.

All dimensions are in inches [millimeters].
Specifications and features are subject to change without notice.

* See instruction sheet for full list.
  • Highly resistant to electrical and magnetic motor and brake noise
  • Auxiliary channel offers separate low frequency outputs (1/4) at no extra charge on each output
  • Marker Pulse Standard
  • Available C-Face tether kits (4.5" to 16")
  • Available threaded rod torque arm
  • Optional OSHA finger guard
  • Optional shaft grounding brush
  • Optional dual output for backup, complete isolation between outputs
  • 1 Year No-Hassle Warranty
Industry General Food & Beverage Pulp & Paper Wood Products Wind Power Crane & Hoist Metals Mining Marine Oil & Gas

Light Mill Duty

AV20, AV25, AV6A, AV6M, Avtron Elevator Encoder, Cables and Connectors, Encoder Couplings, Encoder Programming Tool, HS25A, HS35A, HS6A, K661, SC65

Mill Duty

AV32, Cables and Connectors, Encoder Couplings, HS35M, HS35X, HS6M, K661, M185, M3, M3(small), RAHS35M

Heavy Mill Duty

AV115, AV125, AV44, AV45, AV56, AV56-Wind, AV56S, AV67, AV85, AV850, AVSK, Cables and Connectors, Carlen Replacement, HS44, HS45, K661, M4, M4(small), XP5, XR115, XR12, XR125, XR45, XR4F, XR5, XR56, XR67, XR85, XR850, XR97, XRB1, XRB2, XRB3

Severe Mill Duty

AV12, AV30, AV485, AV5, AV685, Cables and Connectors, Carlen Replacement, Encoder Couplings, HS40, K661, M484, M6, M6C, M7, XP5, XPH1, XPH8, XR12, XR485, XR5, XR685, XR97, XRB1, XRB2, XRB3,
Avtron's M3 large bore encoders directly replace and provide a great upgrade from competitive models, including:

BEI:  HS45 encoders

Dynapar:  HS35, HS35R encoders

Northstar:  HSD35, HSD37, HSD38, HS56, HS85, Magcoder, MH encoder

Leine and Linde:  861, 862, 863, 865 encoders

Baumer Hubner:  AG 14, EGZ 14, HOG 12, HOG 161

And other hollow shaft mount encoder models, shaft sizes 1 1/2"- 2 3/8" [48mm-60mm]

For direct model replacements, try our cross reference page
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In This Section

  • Encoder

    A device which indicates position and speed via a set of digital outputs. Incremental encoders output quadrature (A Quad B) signals, and may add a marker pulse once per revolution.  Absolute encoders typically indicate position via a digital message, a set of parallel outputs, or analog values.

  • Incremental Encoder

    An encoder that produces pulses in proportion to distance moved or rotated. Incremental encoders can also have a marker pulse Z, Z NOT (, ) once per revolution to provide a position reference. Avtron produces a full range of incremental rotary encoders.

  • Marker Pulse

    The Marker Pulse occurs once per revolution. The purpose of the marker pulse is to provide a repeatable home position location for positioning applications. The marker pulse is often abbreviated as "ØZ" or "Z" in the USA and "C" or "N" in Europe.

  • Optical Encoder

    An Optical Encoder typically uses a light source shining through, or reflecting off, an optical disk with lines or slots that interrupt the beam of light to an optical sensor. Electronics count the interruptions of the beam and generate the encoder’s output pulses.

  • PPR

    Pulses Per Revolution. Most Avtron encoders output quadrature pulses, with four times as many lines as pulses. Often lines can be counted in the drive/speed controller for higher resolution applications.

  • Sensor Crash

    When the rotating disk in an encoder contacts the sensor (optical or magnetic/magnetoresistive), it damages or destroys the sensor. Sensor crashes can be caused by excessive vibration, shaft runout, or alignment problems in encoder mounting. Avtron encoders feature Wide-Gap technology to eliminate sensor crashes.

  • Wide-Gap Technology

    Avtron encoders use special optical sensors and magnetoresistive sensors, combined with proprietary circuit designs to allow the sensor to be located much farther from the magnetic rotor or optical disk. This eliminates sensor crashes and makes mounting easy and forgiving of mechanical variation.

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