This document is an installation and maintenance manual for Benzlers Series BS gear units, which are worm reducers, gearboxes, geared motors, and industrial reducers. The manual provides comprehensive information to ensure satisfactory installation and long, trouble-free operation.
Function Description:
Benzlers Series BS gear units are designed to transmit power and modify torque and speed in various industrial applications. They can be supplied as standalone gear units, geared motors, or integrated into larger machinery. The units are particularly suited for use in potentially explosive atmospheres, provided they are correctly installed and maintained according to the EU directive 94/9/EC (ATEX 100a). They are classified for Group II Cat 2 (zones 1 & 21) or Group II Cat 3 (zones 2 & 22) environments.
Important Technical Specifications:
- Unit Identification: Information such as unit type (Model No.), order number, and year of manufacture can be found on the nameplate.
- Lubrication: BS40-BS71 worm gear units are supplied lubricated for life with synthetic oil MOBIL SHC 634, suitable for worm gears. Lubricant replacement is not required during normal operation within an ambient temperature range of ±30°C. However, units operating in potentially explosive atmospheres require oil changes based on operating temperature and time (refer to Table M2 for renewal periods).
- Oil Quantities (Single Units BS40-BS71): BS40: 0.20 liters, BS50: 0.25 liters, BS63: 0.40 liters, BS71: 0.75 liters.
- Oil Quantities (Double Units BS40-BS71): BS40: 0.25 liters, BS50: 0.35 liters, BS63: 0.55 liters, BS71: 0.75 liters.
- Shaft Tolerances: Input or output shaft extension diameter tolerance is ISO j6 (for ≤40 mm) and k6 (for >40 mm). Fitted components should be to ISO tolerance K7. Hollow shaft tolerance is H7.
- Mounting Surface Flatness: Maximum permissible flatness error for the mounting surface is 0.12 mm.
- Bolt Tightening Torques (Quality Class 8.8):
- M4: 2.8 Nm (25 Lbf.in)
- M5: 5.5 Nm (49 Lbf.in)
- M6: 10 Nm (89 Lbf.in)
- M8: 25 Nm (221 Lbf.in)
- M10: 50 Nm (442 Lbf.in)
- M12: 85 Nm (752 Lbf.in)
- M16: 200 Nm (1770 Lbf.in)
- Oil Seal Dimensions:
- BS40: Input Shaft: 20 x 47 x 7 (47 x 6.5*), Output Shaft: 30 x 47 x 7
- BS50: Input Shaft: 20 x 47 x 7 (47 x 6.5*), Output Shaft: 40 x 52 x 7
- BS63: Input Shaft: 30 x 62 x 10 (62 x 7*), Output Shaft: 45 x 60 x 8
- BS71: Input Shaft: 35 x 72 x 10 (72 x 9*), Output Shaft: 50 x 72 x 8
- (*Sealing Cover dimensions)
- Noise Level: The product range satisfies a noise (sound pressure level) of 85 dB(A) or less when measured at 1 meter from the unit surface, in accordance with ISO 8579-1:2002.
- Temperature Class: Customer to specify Temperature Class T3 or T4, and Category 2 or 3 for ATEX environments.
- Torque Arm: The angle between the torque arm and the high-speed shaft must not exceed 20°.
Usage Features:
- Installation: Units should be installed on a flat, vibration-absorbing, and torsionally rigid foundation. Components fitted to shafts should be heated to 80/100°C to aid assembly, avoiding violent forces. Shaft-mounted units require greasing the shaft with Molykote BR2 or equivalent before fitting.
- Alignment: Proper shaft alignment is crucial to prevent vibration and stress on bearings and gearing. The manual details procedures for checking angularity and eccentricity using block gauges and dial indicators. Allowable angularity gap (G) for rigid couplings is 0.0005 D (where D is the diameter at which the gap is measured), and for other types, refer to the manual. Allowable eccentricity for rigid couplings is 0.025 mm.
- Running-in: For optimal performance, gear units should be run-in under partial load for the first 10-30 hours, gradually increasing to full load. If partial load is not possible, run under no load for several hours, then under load with regular cool-down intervals.
- Motor Connection: Electrical connections to the mains supply must be made by a qualified person, ensuring correct cable sizing and adherence to electrical regulations. Motor terminal wiring diagrams are provided for Delta (low voltage) and Star (high voltage) circuits.
- ATEX Compliance: For units in potentially explosive atmospheres, ensure proper ventilation, ambient temperature within lubricant recommendations, and electrical grounding. Guards and covers must be dust-tight to prevent dust buildup in Zone 21 & 22 areas. Plastic protection covers are only suitable for Category 3 (Zone 2 & 22).
Maintenance Features:
- Periodic Inspection: For units with a level indicating device, check the oil level every 1000 hours or 6 months, whichever comes sooner. Top up with the recommended lubricant if necessary.
- Oil Changes: While BS40-BS71 units are generally lubricated for life, those in explosive atmospheres require oil changes. The frequency depends on oil temperature, type of oil, environment (humidity, dust), and operating conditions (shock, loading). Initial oil fill in a new gear unit should be changed after 1000 hours or one year, or half the specified life, whichever is sooner.
- Oil Plug/Ventilator Removal: Ensure the unit has cooled sufficiently before removing plugs to prevent burns. Do not stand over plugs during removal due to potential pressure build-up.
- Bearing Replacement: Bearings should be replaced every 5 years for ATEX-marked units.
- Cleaning: Periodically clean dirt or dust from the gear unit and electric motor cooling fins and fan guard to aid cooling. Dirt/dust buildup should not exceed 5 mm.
- Troubleshooting: The manual includes a fault diagnosis section for common gear unit problems such as non-rotating output shaft, unusual running noise, and oil leakage, along with possible causes and remedies.
- Safety: Always de-energize the drive and secure against unintentional switch-on before maintenance. Wait for the unit to cool down to avoid hot surface burns. Do not mix synthetic with mineral lubricants, and avoid overfilling to prevent leakage and overheating.
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