Schneider / Lexium servo drives and motors

Two of the most common Lexium call-outs are not faults. Sto and nA on the display mean the drive is working correctly and something else is missing.

Lexium is the Schneider servo range. Lexium 32 drives from 0.15 kW to 11 kW with BMH and BSH motors, on packaging, labelling and machine building across New Zealand.

Sto and nA are not faults

Worth putting first, because these two account for a lot of unnecessary drive replacements.

Neither is a hardware failure. A drive showing Sto has an open safety circuit somewhere: a guard, an E-stop, a safety relay contact. A drive showing nA has control power but no main power.

Check both before ordering anything.

Actual fault codes

Real faults display as E followed by four digits, scrolling on the 7-segment display.

E 7339 is usually mechanical rather than electrical. A jam, high friction on the axis, a slipping shaft coupling, or servo gains set too low. Replacing the drive fixes none of those.

SoMove gives a plain text description and a message history log, which is the fastest way to find an intermittent trip.

Reading a Lexium 32 type code

Take LXM32AD30N4.

The same power and voltage convention as Altivar

Useful, because if you can read one you can read the other.

Same convention as the Altivar drives.

An S at position 12 means a custom build

An important one. Schneider states that in the case of a customised version, position 12 of the type code is an S, and the subsequent number defines the customised version.

The example given is LXM32••••••S123.

A drive with an S and a number in that position is not a standard product. A standard drive of the same rating may not behave the same, because the customisation could be firmware, parameters or hardware.

If your drive has one, send us the whole code including the S number. Do not assume the base reference is equivalent.

The four Lexium 32 models

The A has fixed communication and the M does not

This is the selection decision that matters.

An LXM32A has CANopen and CANmotion built in and that is what it does. If the machine needs PROFINET or EtherCAT, an LXM32A cannot be made to do it.

The LXM32M takes a fieldbus module, and the available modules cover:

So an LXM32M is a different part from its fieldbus module. A used LXM32M may arrive without one, and the module is what makes it talk to your controller.

Tell us which fieldbus the machine uses and we will confirm whether you need the module as well.

The encoder module

An optional module adds a second encoder interface for digital or analogue encoders.

And a useful side effect: Schneider notes that if an encoder module is installed, additional motors can be used. So the module widens motor compatibility as well as adding feedback.

Safety: what is on board and what needs the module

STO comes with every drive. Everything else needs the enhanced safety module eSM.

That matters on a machine where an operator needs to work at reduced speed with a guard open. SLS is what allows that, and a drive without an eSM cannot provide it.

If the existing drive has an eSM, a replacement without one loses those safety functions. As with every safety part on this site, whether a substitution is valid belongs with whoever holds the machine's assessment.

Schneider also notes further conditions must be fulfilled when using the eSM, including on motor selection.

The memory card enables fast replacement

Genuinely useful and easy to miss.

Schneider specifies a memory card slot for backup and copying of parameters and fast device replacement.

So a Lexium can be replaced by moving the card across rather than recommissioning. That turns a tuning job into a swap.

Two consequences:

Keep the card from a failed drive. It holds the parameter set.

Use the card as a backup even when nothing is wrong. A card written today is what saves the outage in two years.

Third Schneider platform on this site where a removable card carries what matters, after the Premium PCMCIA and the M340 memory card.

The motor must meet a minimum inductance

A technical constraint that catches people fitting a non-Schneider motor.

Schneider specifies a minimum inductance value for the connected motor, which limits the current ripple of the peak output current.

If the motor inductance is below that minimum, Schneider warns this may adversely affect current control and trigger motor phase current monitoring.

So a drive tripping on phase current monitoring with a substituted motor is behaving as designed. The motor is wrong for the drive, not the other way round.

The supported families are BMH and BSH. Selection depends on the mains voltage and the motor inductance, and other motors need checking with Schneider.

A stiff supply may need a reactor

Counter-intuitive and worth knowing.

Schneider rates the drives at a mains impedance corresponding to a short circuit current of 1 kA.

And states: if the supply mains has a higher short circuit current than indicated in the technical data, use upstream mains reactors.

So a strong supply is not automatically better. A drive close to a large transformer sees a stiffer supply than the drive is rated for, and the harmonic currents rise accordingly.

If a bank of drives sits near the incomer and they keep failing, that is worth checking. Mains reactors are listed in the Schneider accessories and spare parts section.

Fuses and protection

Note that Schneider permits lower ratings, provided the device does not trip at the drive's input current. So the published figure is a maximum rather than a requirement.

Motors

Drive and motor are matched. Send both references, plus the feedback type, when quoting either.

The wider Lexium range

Software

Lexium uses SoMove, the same tool as Altivar drives and Altistart soft starters.

One tool across drives, servos and soft starters is a real advantage on a mixed Schneider site.

Installation features worth knowing

• Side-by-side mounting, so no clearance needed between drives
• Colour coded connectors on the front panel or top
• Automatic parameter calculation, speed observer and band-stop filter for vibration reduction

Side-by-side mounting matters on a multi-axis panel. Six drives with no gaps is a much narrower panel than six with clearance.

What to send us

The full type code, including anything after an S at position 12.

The motor reference.

Which fieldbus, if it is an LXM32M.

Whether an eSM safety module is fitted.

Whether you have the memory card.

The fault code, if there is one. Sto and nA are not faults.

What we can supply

Current production. Lexium 32 drives across all four models, BMH and BSH motors, fieldbus modules, encoder modules, eSM safety modules, memory cards, mains reactors and braking resistors. Quoted with a delivered lead time.

Earlier ranges. Lexium 15, Lexium 05 and other superseded servo. Surplus and tested used.

Modules separately. A fieldbus or safety module failure does not need a new drive.

We buy Lexium

Lexium drives and BMH and BSH motors hold value, and matched pairs are worth more together. Keep the memory cards and modules with the drives. See Sell To Us.

Related

Schneider overview. Altivar drives, which share the type code convention and the SoMove software.

For servo from other brands see Allen-Bradley Kinetix, Omron G5 and 1S and ABB MicroFlex.

Send us your type codes

If the display shows Sto or nA, check the safety circuit and the main supply before ordering. Those are not faults. Quotes in NZD including GST.

Request a quote

Industech is an independent supplier of new, surplus and used industrial automation equipment. We are not an authorised distributor of, approved by, sanctioned by, or affiliated with Schneider Electric. Schneider Electric, Lexium and SoMove are trademarks of Schneider Electric. All trademarks, brand names and type codes are the property of their respective owners and are used here for identification purposes only. Information on this page is for identification and does not constitute a safety assessment.