Mitsubishi HA103NC-S (HA1O3NC-S) AC Servo Motor — 2kW, 3000 rpm, MELDAS HA-NC Series

Product Overview

Part Number: HA103NC-S 

Also Referenced As: HA1O3NC-S / HA103NCS

Manufacturer: Mitsubishi Electric

Series: MELDAS HA-NC Series

Spec No.: 7Z134

The Mitsubishi HA103NC-S is a 2-kilowatt AC servo motor built specifically for Mitsubishi's MELDAS CNC platform. Where general-purpose MELSERVO motors are designed for broad industrial automation use, the HA-NC series was developed as a machine-tool-dedicated motor family — matched to the MDS-A and MDS-B series servo drive units and the MELDAS numerical control systems that powered a generation of Mitsubishi-controlled machining centres, vertical lathes, and multi-axis CNC machines.

At 2kW and 3,000 rpm rated speed, the HA103NC-S occupies the mid-capacity position in the HA-NC family. Its rated current of 9.2A at 170VAC reflects the motor's design point for sustained axis duty: sufficient torque delivery for cutting feed axes while maintaining thermal stability over long production runs.

Electrical & Performance Specifications

The MELDAS HA-NC Series: Built for CNC, Not for General Use

There is a meaningful difference between Mitsubishi's general-purpose MELSERVO motors (HC-SF, HC-SFS, HF, HG families) and the HA-NC series. The HA-NC motors were developed as an integral part of the MELDAS CNC ecosystem — Mitsubishi's machine-tool numerical control platform that powered a large installed base of machining centres and turning centres from the 1990s through to the mid-2000s.

These motors interface with MELDAS drive units — primarily the MDS-A and MDS-B series servo modules — through a dedicated connection scheme documented in Mitsubishi's MELDAS servo specifications manuals. The drive unit reads encoder feedback from the OSE104 encoder fitted to the HA103NC-S, and the MELDAS CNC unit manages the full position loop as part of its axis interpolation. This tight integration between motor, drive, and CNC controller is why HA-NC motors are essentially non-interchangeable with other servo families: the feedback protocol, the drive connection pinout, and the CNC parameter tables all assume this specific motor series.

The HA-NC family also carries an important hardware note: these motors use ferrite permanent magnets. Ferrite magnets are susceptible to partial demagnetisation under specific conditions — a hard mechanical crash that applies sudden shock load to the rotor, or a servo drive fault that sends an abnormal current burst through the motor windings. A demagnetised HA103NC-S will deliver reduced torque and may exhibit hunting or instability during closed-loop operation. This is recoverable: specialist repair facilities can re-magnetise ferrite-magnet motors as part of a full rebuild, restoring rated performance. It is, however, a consideration that distinguishes these older-generation motors from modern rare-earth magnet designs.

OSE104 Encoder

The OSE104 fitted to the HA103NC-S is an optical serial encoder providing position feedback to the MELDAS drive unit. The serial interface — rather than a parallel A/B/Z pulse output — transmits position and speed data as a serial packet, which reduces cable conductor count compared to parallel encoder wiring while providing the resolution the MELDAS CNC needs for accurate position interpolation.

Encoder condition is critical to HA103NC-S performance. Several common failure modes originate at the encoder rather than the motor windings: contamination of the optical disc from bearing grease migration, hairline cracks in the encoder disc from shock events, or degraded LED output from extended service hours. A MELDAS CNC reporting an encoder error alarm on an HA103NC-S axis is frequently pointing at the OSE104 assembly rather than an electrical fault in the motor itself.

For machines undergoing repair, the encoder and motor are typically serviced together. The OSE104 is available as a separate replacement item, but installation requires careful shaft-to-encoder alignment and correct cable routing to avoid flex fatigue at the connector.

Typical Machine Tool Applications

The HA103NC-S was standard equipment on Mitsubishi-branded machining centres and appears as original equipment in a range of Japanese-built machining platforms that specified MELDAS controls. Typical axis assignments include:

Vertical machining centre feed axes (X, Y, Z). The X and Y table axes of a vertical machining centre require motors capable of sustained torque during contouring operations and rapid traverse between positions. At 2kW, the HA103NC-S is appropriately sized for medium-capacity VMC tables — providing the torque needed for ball-screw preload, friction, and moderate cutting feed forces across the full speed range.

Horizontal machining centre pallet and table axes. HMC configurations often use the HA-NC series for the rotary B-axis or pallet change positioning axes where the load profile involves high peak torque demand during indexing followed by a sustained hold at the indexed position.

CNC lathe turret index axes. On Mitsubishi MELDAS-controlled turning centres, the turret index drive requires fast acceleration to an indexed position and positive hold during cutting. The 2kW output and 3,000 rpm rated speed of the HA103NC-S is well-matched to this duty cycle.

Rotary table axes on multi-axis platforms. Fourth-axis rotary table drives in the HA-NC motor range rely on the tight MELDAS integration for synchronised contouring where the rotary axis must interpolate with the linear axes simultaneously.

The HA-NC Family Context

The HA-NC naming follows Mitsubishi's MELDAS motor convention, where the middle digits indicate motor capacity. Within this family:

The HA103NC-S and HA103NCB-S are identical in all electrical and mechanical respects except that the NCB variant adds a spring-applied, 24V DC release electromagnetic brake — required for any vertical axis application where gravity would cause uncontrolled descent on servo-off or power loss.

Sourcing & Repair Considerations

The HA103NC-S has been out of production for a number of years. Three categories of supply are available in the market:

New-old-stock (NOS). Genuine Mitsubishi-manufactured units that have never been operated, held in storage since original production. NOS units carry no operational wear but may have experienced bearing grease degradation or encoder LED dimming from extended storage — both addressable through inspection before installation.

Refurbished / rebuilt. The preferred option for high-cycle applications. A properly rebuilt HA103NC-S will have had the bearings replaced, ferrite magnets re-magnetised to rated flux, encoder assembly cleaned and verified, winding insulation tested, and the complete motor run-tested against a MELDAS drive system. The result is a motor whose remaining service life reflects the quality of the rebuild rather than the age of the housing.

Repair of failed units. If the machine is down and only the original motor is available, repair is a viable path — provided the motor is sent to a facility with both the test equipment to verify encoder output and the capability to re-magnetise ferrite rotors. General-purpose servo repair shops without MELDAS test capability may return a motor that passes basic electrical tests but fails under closed-loop MELDAS control.

Installation Notes for Maintenance Engineers

Reinstalling an HA103NC-S after motor exchange requires attention to a few points specific to the MELDAS system:

Encoder cable routing. The OSE104 serial encoder cable should be routed away from the motor power cable and any high-current switching lines. Running the encoder cable parallel to the motor power cable over any significant length can introduce interference into the serial signal, causing intermittent communication errors that are difficult to trace.

Coupling alignment. The HA103NC-S weight (approximately 21.8 kg) and the relatively stiff MELDAS position loop mean that even small angular misalignment at the ball-screw coupling will produce a periodic torque disturbance at shaft frequency. Align couplings to the tightest practical tolerance and confirm there is no runout at the coupling hub before final bolt-down.

MELDAS parameter verification. After replacement, verify the motor type parameter in the MELDAS CNC matches the HA103NC-S. Incorrect motor parameters affect the current loop tuning and the encoder scaling — either can produce oscillation, alarm-out, or sluggish response that mimics a mechanical problem.

Magnet check before installation. On any used or refurbished HA103NC-S, a no-load back-EMF test (slowly rotating the shaft by hand and measuring the open-circuit voltage) provides a quick confirmation that the ferrite magnets are at or near rated flux. A significantly lower-than-expected back-EMF voltage is a reliable indicator of partial demagnetisation before the motor is installed in the machine.

FAQ

Q1: What servo drive units are compatible with the Mitsubishi HA103NC-S?

The HA103NC-S is designed for Mitsubishi's MELDAS servo drive families — specifically the MDS-A and MDS-B series drive units used in MELDAS CNC systems. It is not electrically or functionally compatible with MELSERVO general-purpose amplifiers such as the MR-J2S or MR-J3 series, which use different encoder interfaces and connection schemes.

Q2: What does the OSE104 encoder provide, and can it be replaced separately?

The OSE104 is an optical serial encoder that provides position and speed feedback to the MELDAS drive unit. It is available as a separate replacement component, making it possible to renew a worn or damaged encoder without replacing the complete motor body. Any encoder replacement should be followed by an alignment check and a run-test against the MELDAS drive before returning the axis to production.

Q3: The motor uses ferrite magnets — what does that mean for maintenance?

Ferrite magnets can lose magnetic flux strength if the motor is subjected to a hard mechanical crash or an abnormal current event from a drive fault. A demagnetised rotor produces reduced torque and unstable closed-loop behaviour. The condition is repairable — specialist facilities can re-magnetise ferrite-magnet servo motors — but it does mean that crash events should be followed by a motor inspection rather than simply re-homing the axis and resuming production.

Q4: What is the difference between the HA103NC-S and the HA103NCB-S?

The only difference is the electromagnetic brake. The HA103NCB-S incorporates a spring-applied, 24V DC release holding brake — required for vertical axes where the motor must hold position on power-down or e-stop. The HA103NC-S has no brake and is suitable for horizontal axes or applications where a mechanical counterbalance provides the holding force.

Q5: Is the HA103NC-S interchangeable with any currently manufactured Mitsubishi motor?

No direct drop-in replacement exists. Newer Mitsubishi servo motors (HF, HG series) use different encoder protocols and are only compatible with current-generation MR-J3/J4 amplifiers. Migrating to a modern equivalent requires replacing both the motor and the MELDAS servo drive unit simultaneously, along with MELDAS parameter updates — this is a system-level upgrade, not a motor swap.