Avtron M4-(3-5, A-F) Small Bore Encoders

Avtron M4-(3-5, A-F) Small Bore Encoders

Obsolete, Replaced by HS45

  • No Longer Available-Replaced by HS45
  • See documents tab for HS45 upgrade benefits
Outline Drawing

Avtron M4 hollow shaft encoder, 5/8" to 1 1/8" [16-25mm] has been replaced with the HS45 upgraded model, which offers larger bearings and potted construction for increased durability, as well as LED and remote diagnostics.  HS45 replaces these models with no rewiring and no mechanical changes.

Looking for M4-1 or M4-2 solid shaft models?  These were replaced by the upgraded AV485 encoder, offering severe duty construction with larger bearings and potted electronics as well.
Looking for M4 large-bore models > 1 1/8"/48mm shaft size?  They are a current model, click here for the M4-Large-Bore encoder.

Check out our cross reference page for updated models.

Operating Power: 5-24 VDC; Current 120mA, no load
Output Format: A,A–, B,B–; Optional Marker Z,Z–
Frequency Range: 0 to 100 KHz
PPR: 240-1200
  • 5000 RPM Max. Std., shafts 5/8" 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.
  • No longer available-replaced by HS45
  • Replaces Lakeshore HS85 and HS56
  • Optional stub shaft kits for GE motors, 180-6000 Frame
  • Available C-Face tether kits (4.5" to 16")
  • Available threaded rod torque arm
  • Optional OSHA finger guard
  • Highly resistant to electrical and magnetic motor and brake noise
  • Second isolated output may be different PPR
Industry General Food & Beverage Pulp & Paper Wood Products Wind Power Crane & Hoist Metals Mining Marine Oil & Gas

Light Mill Duty

AV20, AV25, AV32, AV6A, AV6M, HS25A, HS35A, HS6A, HS6M, K661,

Mill Duty

AV32, HS35M, K661, M185, M3, M3(small), RAHS35M

Heavy Mill Duty

AV115, AV125, AV45, AV5, AV56, AV56S, AV67, AV85, AV850, AV850Test, AVSK, Carlen Replacement, HS45, K661, M4, M4(small), XR115, XR12, XR125, XR45, XR4F, XR5, XR56, XR85, XR850, XR97, XRB1, XRB2

Severe Mill Duty

AV12, AV30, AV485, AV5, AV685, Carlen Replacement, HS40, K661, M484, M6, M6C, M7, XR12, XR485, XR5, XR685, XR97, XRB1, XRB2,

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In This Section

  • A Quad B

    A Quad B refers to the set of output quadrature signals from an incremental quadrature encoder to indicate speed and direction, including complements: A, A NOT, B, B NOT (, , , ). Most Avtron encoders offer A Quad B output at no extra cost.  For more information on quadrature- Wikipedia: http://en.wikipedia.org/wiki/Quadrature_phase

  • Anti-Rotation Arm

    A device used to prevent hollow shaft encoders from spinning with the shaft rotation. It is also called a tether or a torque arm. To prevent encoder bearing damage, anti-rotation arms are very flexible and permit all movements, including axial shaft movement but not rotation.

  • Axial Shaft Movement

    Motor shaft movement in or out, relative to the ends of the motor. Often motors that use roller or sleeve bearing construction have more axial shaft movement. Most Avtron modular encoders tolerate +/- 0.050" of axial movement maximum. Use hollow shaft encoders for high axial movement motor styles, such as MD motors. Most competitors’ modular encoders tolerate much less axial movement than Avtron products.

  • 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.

  • Hollow Shaft

    Hollow Shaft encoders mount by passing the shaft of the motor into or through the encoder. Hollow shaft encoders are easy to mount and replace but are vulnerable to damage. Also, the weight of the encoder must be considered for small motor shafts < 0.75" diameter. Avtron offers a full range of hollow shaft encoders, including: AV685, HS25A, HS35A, HS35M, M3, M4, M6, M7, XP45.

  • Industrial EPIC

    The preferred encoder connector of most users in North America. It contains a full size terminal strip and, unlike the MS connector, requires no soldering for quick field connections. Avtron offers pin-for-pin exact replacements for competitors’ models using industrial EPIC® style connectors. EPIC® is a registered trademark of the Lapp Group.

  • Magnetic Encoder

    Magnetic and magnetoresistive encoders typically use a magnetized rotor with north and south poles lined up around the perimeter of the disk. A magnetoresistive sensor detects the transitions, and these are the counts or pulses generated by the encoder. Magnetic encoders withstand dirt, dust, water, and temperature changes far better than optical encoders.

  • Mill Duty

    Mill Duty encoders are sturdier than light mill duty and can withstand more shock, vibration, and bearing loads. Mill duty encoders must be protected from temperature cycling and contaminants.

  • MS Connector

    The most used encoder connector style in North America. Available in 6, 7, and 10 pin versions, with 10 pins being the most common. Avtron offers pin-for-pin exact replacements for competitors’ models using MS connectors. MS connectors are extremely reliable but require soldering. Many users prefer industrial EPIC ® style connectors instead. EPIC® is a registered trademark of the Lapp Group.

  • 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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