Fanuc A06B-6240-H306 Power Supply Module Used Nice Ao6B-624o-H3o6 A06B6240H306 stock price

Fanuc A06B-6240-H306 | Alpha i Three-Axis Servo Amplifier Module αiSV 20/20/40-B — 6.5A / 6.5A / 13A, 283–339V DC, FSSB, CNC 30i / 31i / 32i-B

Overview

The Fanuc A06B-6240-H306 is a three-axis αiSV-B series servo amplifier module — the B-generation evolution of Fanuc's alpha i servo drive platform, designed to power three independent servo axes from a single compact unit within the modular FSSB servo system.

Its asymmetric current rating — two 6.5A output channels on the L and M axes, stepping up to 13A on the N axis — reflects the engineering reality of a typical three-axis machining centre, where two lighter axes and one heavier axis (or a rotary fourth axis) can share a common three-channel drive without over-specifying each channel.

The A06B-6240-H306 belongs to the A06B-6240 series, which represents Fanuc's B-generation upgrade to the earlier A06B-6114 series.

The transition from the H103/H114 i-generation to the H123/H124/H3xx B-generation brought improvements in power density, energy efficiency, and compatibility with the 30i/31i/32i-B CNC platforms that Fanuc positioned for its most demanding machine tool applications.

Where the earlier i-generation served the 16i/18i/21i and 0i control families, the B-generation targets the high-end 30i/31i/32i-B controls used in five-axis machining centres, precision grinding machines, large turning centres, and complex multi-pallet flexible manufacturing cells.

Consolidating three axes into one module has a direct impact on cabinet space and system cost.

Instead of three separate single-axis SVM1 modules, the A06B-6240-H306 provides the same three-channel drive capability in a single housing that draws power from the shared DC bus supplied by the αiPS power supply module.

For machine builders designing compact electrical cabinets — a priority on shop-floor equipment that has steadily shrunk in the past two decades — this consolidation translates to more usable cabinet volume for other components, shorter inter-module wiring, and fewer connectors to maintain.

All three axes communicate with the CNC through a single FSSB optical fibre daisy-chain — the L, M, and N axes within the A06B-6240-H306 are each individually addressed by the CNC's FSSB configuration, and each responds independently within the module.

The module's internal architecture handles the three-axis current control, IPM gate drive, and encoder feedback for all three channels, while presenting each axis as an independent controlled entity to the CNC's servo loop computation.

Key Specifications

αiSV-B Generation — What the B Designation Means

Fanuc's B designation on the αiSV-B series is not cosmetic. The A06B-6240 series incorporates circuit design improvements over the A06B-6114 i-generation that reduce switching losses in the IPM transistor stages, improve the thermal management of the drive under sustained high-current demand, and tighten the integration with the 30i/31i/32i-B CNC's servo control requirements.

These improvements matter most in applications where the servo axes operate close to their rated current for extended periods — deep cutting operations, high-feed profiling passes, or multi-axis interpolation where all three channels draw current simultaneously.

The B generation also carries revised protection thresholds and alarm logic that align with the 30i/31i/32i-B CNC's expanded diagnostic capabilities.

When an over-current, over-temperature, or IPM fault occurs, the amplifier's alarm code appears on the CNC's servo maintenance screen with more granular information than the earlier i-generation provided, which speeds up fault isolation during maintenance. 

The LED indicator on the front panel of the A06B-6240-H306 provides a quick visual reference for field technicians without needing to navigate into the CNC's maintenance screens — a practical time-saving feature when an amplifier fault stops the machine in a production environment.

Three-Axis Integration — Practical Cabinet Benefits

A machining centre with X, Y, and Z axes driven by alpha i servo motors in the small-to-medium torque range can have all three axes served by a single A06B-6240-H306.

The alternative — three A06B-6240-H123 (αiSV 20-B single-axis) modules — would occupy three separate module slots and require three sets of DC bus bar connections within the drive rack.

The H306 achieves the same three-axis drive capability with one set of DC bus connections, one battery unit, and one FSSB fibre chain segment.

The asymmetric current rating (20A transistor on L and M, 40A transistor on N) is a deliberate product decision: it covers the common machine configuration where two lighter axes and one heavier axis are grouped.

If all three axes require the 13A (40A transistor) rating, the three-axis H307 or individual single-axis modules are the appropriate selection.

Before specifying the H306 for a retrofit or repair, verify the peak and continuous current demand of each motor connected to the L, M, and N axes against the module's per-axis ratings.

FSSB in the B-Generation Context

The FSSB optical fibre link that connects the 30i/31i/32i-B CNC to the A06B-6240-H306 operates at a higher communication bandwidth than the FSSB implementation in the earlier 16i/18i generation drives.

This is not visible as a specification difference in the amplifier hardware per se — the same fibre connectors and cable types are used — but the CNC's servo card on the 30i/31i/32i-B platform has been designed to take advantage of the FSSB bandwidth for faster servo data exchange, which supports the tighter following error budgets that high-accuracy contouring on these controls demands.

The three axes within the A06B-6240-H306 each occupy one FSSB axis slot.

The CNC's FSSB configuration assigns axis numbers to each slot in the fibre chain during system startup. For a machine using the H306 as axes 1, 2, and 3 in the FSSB chain, the CNC identifies all three within the same module and maintains independent servo loops for each.

If one axis develops a fault, the other two remain available depending on the fault type and the machine's safety configuration.

Fault Diagnosis and Serviceable Components

The A06B-6240-H306's 7-segment LED display on the front panel shows drive status and alarm codes. Normal operating states display as numerical readouts; alarm states show alphanumeric codes that reference specific fault categories. Common fault patterns include:

Alarm 6 / Alarm b — Over-current or IPM fault on one or more axes.

Check motor power cables for insulation breakdown, motor winding resistance for shorts between phases or to ground, and connector integrity at the motor junction box.

An IPM fault that persists with the motor disconnected points to a failed transistor module inside the drive.

Alarm 5 (LVDC) — Low DC bus voltage from the aiPS supply. Check the aiPS for its own alarm condition before assuming the H306 is at fault.

The aiPS and H306 share the same DC bus; a power supply issue affects all modules on the bus simultaneously.

Alarm 1 (FAL) — Internal cooling fan has stopped. The fan in the H306 is separately available and replaceable without replacing the entire module.

Check the fan connectors before condemning the module on a fan fault.

At the component level, the IPM transistor modules for each axis, the internal cooling fan, the encoder battery, and the DC bus fuses are available as separate spare parts and can be replaced by qualified service engineers during a module overhaul, extending the service life of the unit without a full module exchange.

FAQ

Q1: Can the A06B-6240-H306 drive beta i series (βiS) motors in addition to alpha i motors?

Yes. Beta i series motors that fall within the current ratings of each axis — particularly the lighter βiS motors (0.4, 0.5, 1, 2kW class) that pair with the L and M axis's 6.5A output, and medium βiS motors compatible with the N axis's 13A — can be driven by the H306 with the appropriate motor type parameter entries in the CNC's servo configuration.

Confirm the specific βiS motor's rated current against the applicable axis channel before connecting. The CNC parameter No. 2020 motor type entry must match the physically connected motor.

Q2: Can the A06B-6240-H306 be mixed with A06B-6114-H1xx i-generation SVM modules on the same drive bus?

No. The A06B-6240 B-generation series operates with the A06B-6200 series αiPS power supplies and uses the control power distribution architecture of the 30i/31i/32i-B system. The A06B-6114 i-generation series operates with A06B-6110 series aiPS power supplies.

The two generations have different DC bus hardware interfaces and different control power distribution, and they cannot share the same drive bus or power supply within a single system. 

Any retrofit that replaces i-generation SVM modules with B-generation H306 modules must also address the power supply compatibility.

Q3: What is the correct approach when one of the three axes in the A06B-6240-H306 develops a fault, and the other two are functioning normally?

First, isolate whether the fault is in the motor, the motor power cable, or the amplifier itself. Disconnect the faulted axis motor power cable at the amplifier connection point and power on the CNC — if the alarm clears with the motor disconnected, the fault is in the motor or cable, not the amplifier.

If the alarm remains with the motor disconnected, the amplifier's transistor stage or control circuit for that axis has failed and the module requires service or exchange.

The two functioning axes can remain operational during diagnosis as long as the machine's safety logic permits running a partially alarmed drive system, but production on the faulted axis cannot resume until the fault is resolved.

Q4: What parameters need to be set when replacing a faulty A06B-6240-H306 with a new or refurbished unit?

The servo parameters that directly link the amplifier to the specific motors are stored in the CNC, not in the amplifier — so a straight amplifier replacement (same H306 to H306) typically does not require parameter changes, provided the replacement unit's hardware configuration matches the original.

However, after fitting any new amplifier, verify that the CNC's amplifier initialisation completes without SV5136 (motor type mismatch) or SV5061 (servo error overflow) alarms. Check FSSB axis assignment via the servo maintenance screen to confirm all three axes are correctly identified.

If the replacement unit has a different hardware revision, consult the Fanuc servo startup guide for any revision-specific parameter notes.

Q5: How does the 34A rated input current of the A06B-6240-H306 affect αiPS power supply sizing for a multi-drive cabinet?

The αiPS power supply must handle the sum of the rated input currents from all the SVM and αiSP (spindle) modules it supplies.

The H306's 34A is its rated peak input draw — in practice, the average current at typical cutting loads is lower, but the αiPS must be sized to supply the worst-case simultaneous peak demand of all connected modules. 

For a cabinet with one H306 plus a spindle module, add the H306's 34A to the spindle module's rated input, apply a system demand factor (typically 0.7–0.8 for simultaneous heavy operation on all axes), and select the αiPS that exceeds this combined demand.

Undersizing the αiPS relative to the combined module input current produces LVDC alarms under heavy simultaneous axis loading.