Eltra EH 80 Hollow Shaft Servo Encoder

Name: Eltra EH 80 Hollow Shaft Servo Encoder | Seven Star LLC
Brand: Eltra
SKU: EH 80

An 80 mm hollow shaft encoder with very high shock and vibration resistance

The EH 80 series is described by Eltra as 80 mm encoders with very high resistance to shock and vibration, recommended for feedback control on AC servomotors. The mechanical figures back that up: 70 G shock for 11 ms and 30 G vibration from 10 to 2000 Hz, compared with 50 G and 10 G for most of the standard Eltra series.

There are four models. The EH 80C is a blind hollow shaft, the 80K is a blind hollow shaft with rear fixing, the 80P is a through hollow shaft and the 80PG is a through hollow shaft with collar clamping. Resolution goes up to 2048 ppr, the output frequency up to 105 kHz, and bores of 8, 10, 12, 14 and 15 mm are offered depending on model. The housing is glass-fibre reinforced PA66 or PPS.

Design highlights

80 mm encoder with very high shock and vibration resistance
Recommended for feedback control of AC servomotors
Three channel output (A / B / Z) up to 2048 ppr
Supply up to +30 V DC with several electrical interfaces
Output frequency up to 105 kHz
Blind or through hollow shaft up to 15 mm
Shaft mounting by grub screws or collar clamping

Technical specifications

Parameter	Specification
Models	80C blind; 80K blind with rear fixing; 80P through; 80PG through with collar clamping
Resolution	100 to 2048 ppr (100 without zero pulse only)
Supply voltage	5 version: 4.5 to 5.5 V DC; 5/28 version: 4.5 to 30 V DC with reverse polarity protection
Power draw without load	0.8 W max
Max load current	C / P 50 mA per channel; L / RS 20 mA per channel
Output circuits	NPN open collector; push-pull HTL; line driver; RS-422
Max output frequency	105 kHz
Index signal	90°e, gated A and B
Bore diameter	8, 10, 12, 14, 15 mm, by model
Enclosure rating	IP 64 shaft side and IP 65 cover side (C, P, PG); IP 64 (K)
Max rotation speed	3500 rpm (P, PG); 6000 rpm (C, K)
Shock / vibration	70 G, 11 ms / 30 G, 10 to 2000 Hz
Moment of inertia	4 x 10-6 kgm2
Starting torque	Below 0.04 Nm at +20°C
Materials	Housing and bearing stage PA66 or PPS glass fibre reinforced; shaft aluminum (C, K) or stainless steel (P, PG)
Bearings	2 ball bearings, life 109 revolutions
Cable	Shielded, fixed installation, 0.22 mm2, min bend radius 60 mm; standard length 0.3 m
Operating temperature	-20 to +85°C; up to +100°C on demand
Storage temperature	-25 to +85°C
Weight	250 g
MTTFd / mission time	207 years / 20 years per EN ISO 13849-1; DC 0 %
Approvals printed	UL / CSA file E212495; EMC 2014/30/EU; RoHS 2011/65/EU

EH 80 model overview and ordering code

The datasheet example is EH 80C 500 S 5 L 8 X 6 PR . XXX. The model letter changes the bore options, speed limit and shaft material, as listed below.

Code position	Options
80C	Blind hollow shaft; bores 8, 10, 12, 14, 15 mm; 6000 rpm
80K	Blind hollow shaft with rear fixing; bore 10 mm; IP 64; 6000 rpm; mating shaft tolerance h7
80P	Through hollow shaft; bores 8, 10, 12, 14, 15 mm; 3500 rpm
80PG	Through hollow shaft with collar clamping; bores 10, 14 and 15 mm; 3500 rpm
Resolution	100, 200, 250, 256, 360, 400, 500, 512, 600, 1000, 1024, 2000, 2048 ppr
Interface and supply	C, P, L or RS; 5 V or 5 to 28 V DC
Output type	PR radial cable, 0.3 m standard; 1.5, 2, 3, 5 or 10 m optional

Installation and operating notes

Use a g6 mating-shaft tolerance for C, P and PG and h7 for the 80K. Torque pins are listed under Accessories and are needed to prevent the body from rotating on the motor.

The larger shock and vibration ratings make the series appropriate for servo axes that reverse quickly and for motors that vibrate; they do not remove the need to fix the cable so that it does not flex at the exit.

The datasheet states IP 64 on the shaft side and IP 65 on the cover side. Where a motor end shield exposes the shaft side to splash or dust, consider this when choosing a location.

Applications for the EH 80

Servo axes on machine tools, packaging lines, plastic injection and handling equipment benefit from a rugged feedback device that survives repeated acceleration. The temperature figure of up to +100°C on demand extends use near warm motor housings.

This is not a hazardous-area or high-IP product. For classified zones use the Eltra EX 80, and for washdown look at higher IP series. The remark is general selection guidance.

Information to send with an RFQ for the Eltra EH 80

To confirm the right EH 80 variant, provide the following.

Model C, K, P or PG and the motor shaft diameter
Resolution and zero pulse requirement
Supply voltage and output circuit
Maximum speed, ambient temperature and cable length

Commissioning and maintenance notes

Before installation, check that the bore matches the motor shaft and that the anti-rotation fixing does not load the bearings, and avoid hammering the encoder onto the shaft. Match the output type and supply voltage with the servo drive input, and use shielded cable with the shield earthed as described in the manual, kept away from motor power cables. In hot plant rooms in the region, check the operating temperature against the real conditions near the motor, and inspect the connector and cable during routine maintenance.

Keep one spare encoder for critical servo axes to shorten downtime.

Frequently asked questions

How resistant is the EH 80 to shock and vibration?

The datasheet gives 70 G for 11 ms shock and 30 G vibration from 10 to 2000 Hz.

What are the four models?

80C blind hollow shaft, 80K blind with rear fixing, 80P through hollow shaft and 80PG through with collar clamping.

What maximum resolution is offered?

2048 ppr.

What temperature range applies?

-20 to +85°C, with up to +100°C available on demand.

What is the enclosure rating?

IP 64 on the shaft side and IP 65 on the cover side for models C, P and PG; IP 64 for model K.

Encoders for motors, lifts and machinery

Eltra describes application areas such as industrial automation, motor feedback, lift systems, packaging, light material processing, heavy duty industry, off-highway vehicles and potentially explosive atmospheres. Hollow shaft and solid shaft designs, bore sizes from a few millimetres to 40 mm, resolutions up to 24000 ppr and enclosure ratings up to IP 67 are printed in the Eltra datasheets.

Frequently Asked Questions