Eltra ER 38 F/G Miniature Blind Hollow Shaft Incremental Encoder

A miniature 38 mm hollow shaft encoder with up to 14400 ppr and IP 66 / IP 67 protection

The ER 38 is Eltra’s miniaturised hollow shaft range for general factory automation, small AC motors and geared motors. Despite the small body it offers up to 14400 pulses per revolution, an output frequency of up to 500 kHz and a metal cover for high protection, with IP 66 on the shaft side and IP 67 on the cover side.

Two models share the datasheet. The ER 38F is mounted by a stator coupling and the ER 38G by a torque pin that is supplied. The blind hollow shaft is clamped with a collar and takes a bore of up to 10 mm; smaller shafts of 4, 5, 6, 6.35 and 8 mm are covered with a supplied bronze shaft adapter. A weight of 150 g and a moment of inertia of 0.8 x 10-6 kgm2 keep the load on a small shaft low.

Headline features

• Miniaturised encoder for factory automation and small motors
• Three channel output (A / B / Z) with resolution up to 14400 ppr
• Supply up to +30 V DC; several electrical interfaces
• Output frequency up to 500 kHz
• Metal cover for high IP protection
• Blind hollow shaft up to 10 mm with collar clamping
• Stator coupling or torque pin mounting

Technical specifications

Reading the ER 38 ordering code

The datasheet example is ER 38F 500 S 5/30 P 10 X X PR . XXX.

Installation and operating notes

The shaft load limit is only 5 N axial and radial, so rely on the stator coupling or torque pin to take torque and never use the encoder as a bearing support.

Keep the mating shaft free of burrs and use the collar clamp only after fitting the adapter, if one is needed for bores below 10 mm. The recommended interface flange design is drawn in the datasheet.

At the maximum 14400 ppr the output frequency limit of 500 kHz corresponds to about 2080 rpm (derived: 500000 x 60 / 14400), so high resolutions limit useful speed.

Applications for the ER 38

The datasheet lists general factory automation, small AC motors and geared motors. Typical GCC users are food and beverage, water treatment dosing, textile and packaging lines where a small, sealed encoder with a high count is needed on a gearmotor.

The metal cover and IP 66 / 67 rating withstand dust and washdown better than the polymer-body encoders in the EH series, but the datasheet makes no corrosion or salt-spray claim. General guidance.

Information to send with an RFQ for the Eltra ER 38

Send the points below to quote the ER 38.

• Model F or G, and motor shaft diameter
• Resolution and zero pulse
• Supply voltage and output circuit
• Cable length and maximum speed

Related items and documents

For a similar-sized magnetic encoder see EMI 30 and EMI 55 in the Eltra range. Further position and speed feedback devices are shown in encoders. This page carries the datasheet. Seven Star LLC will quote ER 38 after the code, count and destination are confirmed.

Commissioning and maintenance notes

Miniature hollow shaft encoders are used in the region on small motors and geared motors in packaging, printing, textile and labelling machines, and in small automation systems. Before installation, check that the bore matches the shaft and that the anti-rotation fixing does not load the bearings. Avoid hammering the encoder onto the shaft, as the small bearings and optical disc are sensitive to shock.

Match the output type, resolution and supply voltage with the drive or counter input, and check that the input can accept the output frequency at full speed. Use shielded cable with the shield earthed as described in the manual, and keep it away from motor power cables. The IP rating helps in dusty and humid areas, but the cable entry should still be protected from water jets. Inspect the cable and fixing during routine maintenance, and replace damaged cables at once.

When ordering a replacement, record the resolution, output type, bore and connection of the existing encoder, so the new unit fits without changes to the drive settings. Keeping one spare encoder for critical machines shortens downtime.