Product Core Brief

• Model: MHD115C-058-PG1-BA
• Brand: Bosch Rexroth (Indramat Division)
• Series: MHD Permanent Magnet Synchronous Servo Motor family
• Core Function: Deliver high continuous stall torque for heavy vertical/rotary machine axes, provide multiturn absolute position feedback and power-off axis locking via integrated brake
• Product Type: Frame size 115 C-length synchronous servo motor, factory fitted holding brake, PG1 sealed shaft, BA side-A power/signal connector orientation
• Key Specs: 70Nm continuous stall torque | 70Nm 24VDC holding brake | Hiperface multiturn absolute encoder | IP65 enclosure | Natural convection cooling
• Note: OEM active production; factory-new surplus and fully load-tested refurbished inventory available. Matches Indramat IndraDrive C/H drive platforms for machine tool and fab automation axes.

Key Technical Specifications

• Frame Mechanical Dimensions: 192mm mounting flange, 180mm centering bore, C-series stator length
• Continuous Stall Torque: 70 Nm base rated output
• Peak Dynamic Torque: 231 Nm short-duration overload capacity
• Maximum Rated Speed: 6000 rpm
• Rotor Inertia: Low inertia rotor optimized for fast acceleration cycles
• Encoder Interface: PG1 Hiperface multiturn absolute encoder, 4096 revolutions absolute tracking, 128 line incremental resolution
• Shaft Configuration: Plain smooth output shaft with integral contactless shaft sealing ring
• Holding Brake Assembly: 24 VDC coil, 1.29 A coil draw, 70 Nm static holding torque, fail-safe power-off clamping
• Cooling Method: Natural surface convection, no auxiliary blower required for standard duty cycles
• Environmental Protection Class: IP65 housing, sealed stator windings and encoder compartment
• Power Connector Layout: BA code defines power and feedback connectors routed to side A of motor housing
• Operating Ambient Range: -20°C to +60°C continuous cabinet/machine frame operation
• Total Unit Weight: 55 kg
• Compliance Standards: CE, UL, IEC 60034-1, SEMI S2 for cleanroom handling equipment
• Compatible Drive Platforms: IndraDrive C, IndraDrive H digital servo amplifiers

Product Introduction

This high-torque permanent magnet servo targets heavy vertical lift and rotary table axes on machine tools and semiconductor substrate handling equipment. Its low rotor inertia delivers rapid acceleration without sacrificing sustained stall torque under static vertical loads.Integrated multiturn absolute feedback eliminates mandatory homing after emergency power loss, while the factory brake prevents axis drop during unplanned shutdowns. Natural convection cooling removes auxiliary fan maintenance points inside sealed process enclosures.

QA & Testing SOP (Transparency Building)

1. Incoming Inspection: Cross-reference serial and Rexroth order part number R911290479 against OEM vital product databases; visual scan for scratched flange mounting surfaces, cracked encoder housing, oil leakage at shaft seal, and corroded connector pins. All connector orientation and brake wiring pinouts photographed pre-disassembly.
2. Live Bench Testing: Mount motor to rigid dynamometer test stand paired with matching IndraDrive H amplifier; run continuous 24-hour cyclic load profile alternating 0–70Nm stall hold and 0–6000rpm speed ramps. Fluke power analyzer monitors three-phase winding current balance and brake coil draw stability.
3. Electrical & Encoder Testing: Megger winding insulation test >100MΩ between phase windings and motor housing; validate full multiturn absolute position tracking across 4096 revolutions with Hiperface signal analyzer, measure encoder position error <1 count full travel.
4. Brake Functional Validation: Apply 24VDC nominal brake supply, verify full 70Nm static holding capacity via torque fixture; confirm zero shaft drift under full rated vertical load with brake energized deactivated state.
5. Final QC & Packaging: Torque flange mounting studs to OEM specified torque values, cap shaft and connector ports with OEM protective plugs, wrap unit in static-dissipative foam, affix printed QC tag with dynamometer torque curve and encoder linearity test data before sealed wooden crate shipping.

Installation Pitfalls & Guide (Engineer to Engineer)

❗ Connector Orientation Mismatch Risk: BA suffix specifies side-A power/feedback connector routing. Installing a RA/AA suffix replacement unit requires full cable harness rework; misaligned cable routing creates bending stress leading to intermittent encoder feedback loss during axis motion. Photograph original connector layout before motor removal.❗ Vertical Axis Brake Load Oversight Risk: Brake holds 70Nm static torque only at nominal 24VDC coil voltage. 10% rail voltage sag reduces holding capacity by 15%, risking uncontrolled axis drop during power fluctuation events. Verify 24VDC brake supply minimum 23.5V under full machine load.❗ Shaft Seal Contamination Hazard: Removing the factory shaft protective cap before coupling installation scratches the integral PG1 shaft seal, allowing coolant, dust or cleanroom particulate ingress that causes premature bearing failure within 3,000 operating hours.❗ Dynamometer Drive Parameter Mismatch Risk: Winding code 058 defines fixed motor inductance/resistance values stored in drive parameter bank P0-0. Loading parameter sets from MHD115 shorter length variants triggers unstable current regulation and audible stator vibration at mid-speed ranges.❗ Catastrophic Winding ESD Risk: Ungrounded technicians damage internal Hiperface encoder ASIC and winding insulation; certified ESD wrist strap and conductive ground mat mandatory before opening encoder housing or touching exposed shaft/seal surfaces.4-Step Replacement Guide:

1. Pre-install: Execute machine lockout-tagout, fully bleed vertical axis counterbalance pressure if fitted, export all axis motion parameter sets from the IndraDrive amplifier via HMI software.
2. Removal: Disconnect power and encoder connector cables fully, release flange mounting bolts evenly to avoid shaft side-load binding, lift motor with rated capacity overhead hoist, set unit on vibration-dampened ESD foam pad. Record all brake coil wiring pin assignments.
3. Install: Lift replacement motor into aligned mounting bore, torque flange fasteners to OEM torque spec, fit coupling hub without damaging PG1 shaft seal, re-terminate brake and power/encoder cables matching photographed BA side-A routing.
4. Power-on Test: Restore machine three-phase mains and 24VDC brake supply, upload saved drive motor parameter set, run 30-minute cyclic torque/speed test to validate stable encoder position tracking and zero vertical axis drift with brake de-energized.

FAQ (Frequently Asked Questions)

Q: Can this motor replace shorter MHD115 variants like MHD115B-058 on identical IndraDrive racks without parameter rework?A: No cross-compatibility for out-of-box operation. C-length stator creates different rotor inertia and winding inductance values; drive P0 motor parameter table must be fully reloaded and axis loop gains retuned to eliminate speed ripple and position overshoot during production cycles.Q: Does this servo support hot-swapping while machine three-phase mains power remains energized?A: Three-phase power and Hiperface encoder cables carry live high voltage and differential signaling during operation. Live disconnection injects voltage transients that corrupt drive non-volatile motion parameters and risk permanent encoder hardware damage. Full machine mains lockout is mandatory before connector disconnection.Q: What warranty separates factory-new surplus stock from fully refurbished MHD115C-058- units?A: Factory-new Rexroth-certified surplus carries a 12-month industrial warranty covering winding insulation breakdown, encoder signal drift and brake holding torque degradation. Refurbished units ship with a 6-month limited functional warranty; bearings and brake friction liners show measurable wear after extended runtime, reducing long-term static holding consistency.Q: Will swapping this servo erase stored axis motion profiles and vertical position offset values in the IndraDrive amplifier?A: All motion recipes, position offsets and loop gain parameters reside in the drive’s internal flash memory, independent of motor hardware. Export a full parameter backup before motor removal to avoid retuning after installation.Q: Can this hardware operate on older IndraDrive C amplifiers released prior to 2010 without firmware updates?A: The PG1 Hiperface multiturn encoder uses standard protocol compatible with all IndraDrive C firmware versions V1.04 and newer. Units running firmware V1.03 or older require a free Rexroth firmware patch to read full multiturn absolute position data without cycle homing.Q: What expected service window applies to factory-new versus refurbished motors in 24/7 high-volume production environments?A: Factory-new units target scheduled bearing and brake liner replacement at 46,000 operating hours. Refurbished variants degrade at 35,000 hours; reused rolling element bearings develop clearance drift that widens position error bands and triggers machine position deviation faults during wafer or part processing batches.Q: What functional difference separates PG1 and PG0 encoder suffixes on the same MHD115C base motor?A: PG1 includes integral contactless shaft seal and full multiturn absolute Hiperface feedback; PG0 omits the shaft sealing ring and only supplies single-turn absolute encoder data, requiring full machine homing after every power cycle interruption. PG1 is mandatory for cleanroom and coolant-exposed machine axes.