Why a Heavy-Duty Servo as the Common Denominator
Modern automated material-handling lines rarely stop at a single technology. A belt or roller conveyor moves product from point A to point B, then a delta or Cartesian robot lifts, re-orientates, and nests it into packaging. When both subsystems are driven by the same servo platform, design, commissioning, and spare-parts logistics become simpler—especially when the motor in question delivers enough torque overhead for both linear and rotary loads. Bosch Rexroth’s MHD115C-058-PP1-AA, a 192 mm-flange permanent-magnet synchronous motor, sits in that sweet spot: 70 Nm of continuous standstill torque, 231 Nm of peak torque, and a characteristic speed of 4,000 rpm, all inside an IP65 housing and insulation class F package weighing about 55 kg.
Key Electrical and Mechanical Data You Will Need
Before opening DriveTop or IndraWorks to create the axis, keep four factory parameters on your notepad. First, continuous current at standstill (IdN) is 82.5 A at a 60 K over-temperature rise; second, the voltage constant is 86.4 V/1000 rpm; third, the rotor inertia is 1.38 × 10-2 kg·m²; and fourth, the maximum speed is 6,000 rpm. These numbers define the drive-controller rating, the cable cross-sections (16 mm² minimum for natural-convection operation), and the acceleration profile you can safely command without exceeding 371 A peak phase current.
The square 192 mm flange and 180 mm centering relief are dimension-matched to most conveyor gearheads in the 140- to 160-mm frame class, allowing direct-coupled right-angle reducers or in-line planetary stages.
Motor Sizing for Conveyors—An Example Walk-Through
Imagine a 15-metre accumulation conveyor moving 50 kg cartons at 1 m/s on Ø60 mm rollers. Frictional losses bring the required shaft torque to roughly 40 Nm. The MHD115C-058 offers 70 Nm continuous, so even after the 93 % efficiency of a two-stage helical gearbox the axis retains 65 % headroom for acceleration and incline sections. Characteristic speed at the motor is 4,000 rpm; with a 6:1 ratio you still deliver 666 rpm at the roller drive shaft—more than enough linear velocity.
Such oversizing is not wasteful. It lets you run the motor closer to 60 K thermal limits instead of the 100 K endurance boundary, improving bearing life and keeping the winding insulation well below its class F (155 °C) rating during three-shift duty.
Mechanical Integration Details that Matter
Because the pick-and-place cell and the conveyor often share a single welded base, coaxial alignment is critical. The motor’s centering pilot eliminates axial run-out, but installers frequently neglect the four M12 mounting bolts: they must be tightened in a cross pattern to 120 N·m to avoid warping the stator laminations. Matching the motor’s IP65 rating, select cable glands or circular connectors that carry the same ingress-protection code, especially where coolant spray or carton dust is present.
Pairing with IndraDrive C (HCS) or Cs—Parameter Entries That Save Time
The Rexroth drive wizard will ask for:
- Motor part number ➜ select “MHD115C-058” from the library.
- Encoder ➜ default “digital servo feedback, multi-turn.”
- ContTorque @ 0 rpm ➜ 70 Nm.
- ContCurrent @ 0 rpm ➜ 82.5 A.
- Torque constant ➜ 0.95 Nm/A (crest).
Enter those exactly as published to make the auto-tuning routine converge in one pass.
From Conveyor to Robot—Why the Same Motor Fits Both
The robot sitting at the discharge end must accelerate a 25 kg gripper and payload through a 400 mm pick stroke in 0.25 s. Required axis torque peaks near 125 Nm, but only for 120 ms. The MHD115C-058 PP1 AA’s 231 Nm theoretical maximum torque and 371 A peak current mean you can reach that figure without exceeding magnetic saturation, provided the duty cycle stays within Rexroth’s S6-25 % rating. The identical motor and drive family across conveyor and robot simplifies spare-motor stocking and lets the PLC share a single Sercos network for synchronized infeed and robot pick windows.
Coordinated Motion Control
If the conveyor uses an encoder wheel or Rexroth MSK incremental ruler, feed its position into the drive’s integrated “SyncMotion” function. The pick-and-place axis can then phase-lock to the belt so that parts never outrun the gripper. Use the drive-based camming table rather than the PLC for cam execution; the HCS firmware can interpolate 256 points with 125 µs cycle time, keeping jitter under 1 ms.
Thermal and Environmental Safeguards
Even with heavy loads the motor’s winding temperature is the limiting factor, not the surface. Attach a PT100 or KTY sensor to the drive and set the warning threshold at 120 °C. Maintain ambient under 40 °C; above that, derate torque by 10 % per additional 10 °C or add forced air across the housing ribs.
Commissioning Checklist
- Verify cable cross-sections (≥16 mm² power, ≥0.34 mm² feedback).
- Meg-ohm test the insulation to ≥1 MΩ at 500 Vdc.
- Load factory motor file; confirm resolver polarity if using analog feedback.
- Run static torque test at 20 % rated current; vibration ≤1.8 mm/s (ISO 10816-3, Group II).
- Execute autotune, then refine proportional and velocity gains until step response settles <150 ms with <10 % overshoot.
Preventive Maintenance Notes
Because the MHD series uses lifetime-lubricated bearings, the primary wear item is the shaft seal. Replace the Viton ring every 20,000 hours or when gearbox leaks become visible. Keep connector threads below 45 °C; hotter threads indicate excessive cable resistance or loose crimps.
When Repairs or Replacements Are Required
A seized brake, a de-mag event, or a cracked Hall sensor does not mean weeks of downtime. Wake Industrial stocks refurbished MHD115C-058-PP1-AA units and can turn around factory-level repairs—encoder swap, bearing package, laser-balanced rotor—in as little as three business days. For urgent conveyor or robot stoppages, exchange service is available so you can resume production before the next shift. Remember, Wake Industrial is a trusted independent source for Rexroth repairs and replacements, not an authorized distributor of Bosch Rexroth.
Closing Thoughts
Designing a seamless material-handling line starts with components that do double duty. By specifying the MHD115C-058-PP1-AA for both conveyor propulsion and pick-and-place actuation, you gain standardized drive files, common spare parts, and enough dynamic range to handle carton, pouch, or discrete parts with the same mechanical core. If you need help sizing the gearbox, flashing the correct parameter set, or sourcing a drop-in replacement, reach out to Wake Industrial today—engineers are standing by to keep your conveyors rolling and your robots picking with zero unplanned downtime.