Air motors up to 4.4 kW by Mannesmann Demag without integrated brake

Mannesmann Demag Air Motors up to 4.4 kW without Holding Brake – Technical Description and Practical Applications

The Mannesmann Demag series of air motors up to 4.4 kW offers robust, high-torque drives in steel housings, designed for industrial applications without an integrated holding brake. Nominal power ratings from 2.2 kW to 4.4 kW are available with various no-load speeds and characteristic curves, allowing the motors to be precisely adapted to desired torque and speed profiles. Typical designs are based on axial vane or rotary vane principles; material selection, mechanical face seals or elastomer seals, and connection variants determine operational durability and maintenance intervals.

Construction, Materials, and Sealing Technology

The housing is typically made of hardened steel or, less commonly, gray cast iron for special variants, to control vibrations and thermal loads. The shaft is hardened and ground, usually with an H7 fit for feather key or spline hubs. Bearings are low-maintenance ball or roller bearings, depending on axial and radial loads. Combined sealing systems are used for sealing: a primary shaft lip seal (Simmerring) for protection against external contamination and secondary labyrinth or mechanical face seals to minimize internal leakage at high pressure. Material Selection: Steel housing for high impact and pressure resistance, stainless steel options for corrosive environments, and special coatings (e.g., nitriding) to increase wear resistance. Seals made of NBR or HNBR for common compressed air applications; FKM/EPDM versions for higher temperatures or aggressive media.

Connections, Supply, and Control

The motors are supplied via standardized pneumatic connections (G1/4", G3/8", or G1/2" depending on flow rate requirements). Both axial and radial connection variants are available to adapt to installation conditions. Compressed air preparation is mandatory: filters, pressure regulators, and oil mist separators (FRL) upstream of the motor ensure a clean, dried, and correctly lubricated airflow. Lubricant can be added either continuously via upstream oilers or intermittently via lubrication points; some models have internal lubrication channels, while others require external lubrication. Speed control is achieved mechanically via throttle valves or pneumatic proportional valves; for more precise control, pneumatically controlled servo valves or combined pneumatic-electronic control systems are recommended. Despite the lack of a holding brake, an external brake or locking device must be provided for reaction-free holding devices.

Performance, Characteristic Curve, and Efficiency

Power classes from 2.2 to 4.4 kW cover a wide range of industrial drive tasks. The characteristic curves show a linear to slightly non-linear speed reduction with increasing load; usable speed ranges are available depending on the model, with no-load speeds up to, for example, 6,000 rpm. Efficiency values should be checked in the load range: air motors achieve peak efficiencies in medium torque ranges; high no-load speeds significantly reduce efficiency and increase air consumption.

Mounting, Fastening, and Alignment

Mounting surfaces are flat and feature standardized drilling patterns for direct mounting on machine frames or via intermediate flanges. Important mounting instructions: shaft and housing must be mounted stress-free, misalignment avoids increased bearing load and seal damage. For installation in vibration-prone environments, elastomer bearings or vibration-damping adapter plates are recommended. For installation in Ex-zones, compliant versions with appropriate certification are required.

Maintenance and Service Life

Regular inspection of air preparation, monitoring of oil mist, and inspection of seals significantly extend service life. Recommended intervals: visual inspection once a month, seal and bearing inspection every 6–12 months depending on operating hours and operating conditions. Wear parts are standardized and readily available; quick on-site replacement reduces downtime. Documented lubrication schedules and an operating hours log support predictive maintenance.

Application Examples in Production

Applicable as drives for positioning and feeding systems in sheet metal processing, as stirring drives in paint lines, as drives for clamping and tensioning devices, and for rotating tools in potentially explosive atmospheres. Practical example 1: In a conveyor system for body parts, a Mannesmann Demag air motor (3.0 kW, medium speed) replaces an electric direct drive to avoid sparking; mounted on a vibration-damping adapter plate, the motor delivers constant torque with varying contact pressure. Practical example 2: In a paint line, a 2.2 kW motor drives the mixing agitator; thanks to internal lubrication channels and corrosion-resistant coating, the motor operates reliably in aggressive environments. Practical example 3: In a conveyor system for a hazardous materials warehouse, a 4.4 kW motor provides high starting torques for starting long material chains; air supply is provided via a redundant FRL system to ensure constant power output.

Selection Criteria and System Integration

When selecting, the primary factors to evaluate are the required starting and continuous torque, operating speed, environmental conditions (temperature, humidity, corrosion), and installation requirements (space, alignment, connection sizes). For explosion-protected areas, certified models are a prerequisite. Plan the compressed air supply so that pressure stability is maintained during flow rate fluctuations. Integration into controls is done via pneumatic valve islands or via fieldbus-controlled proportional valves; the combination with sensors (speed sensor, pressure sensor) facilitates condition monitoring and automation. Further technical information and application examples can be found at https://maku-industrie.de/technik and https://maku-industrie.de/anwendungsbeispiele.

Safety and Operating Requirements

Since these motors do not have a holding brake, additional safety measures are required if holding functions are demanded: mechanical locking devices, external fail-safe brakes, or pneumatically controlled locking devices. Emergency stop scenarios require integration into the machine control with defined pressure relief strategies to prevent uncontrolled dropping or rotation. Air lines must be designed to be pressure and temperature resistant, with a disconnect point near the motor for quick isolation during maintenance.

Quick Overview: Important Selection Parameters

* Nominal power (2.2–4.4 kW), no-load speed, starting and continuous torque * Housing material, seal material, bearing type * Connection size, air preparation, lubrication concept

FAQs

1. Why choose without a holding brake and how do I secure the holding function?

Air motors without a holding brake are suitable when the application does not require permanent locking or when external safety mechanisms are in place. For safe implementation, use mechanical locking devices, external fail-safe brakes, or pneumatic locking valves in conjunction with control logic that immediately locks upon pressure drop.

2. What air preparation is necessary?

Standard: Filter, pressure regulator, and oil mist separator (FRL). In case of high contamination or humidity, additional dryers and finer filter elements are required. Motors requiring lubrication need a controlled oil mist system; for corrosive environments, special lubricants and sealing materials must be used.

3. How do I choose the right model regarding torque and speed?

Determine the required starting torque and continuous torque at operating speed. Select a model with sufficient reserve torque (typically 20–30% above the expected maximum). Pay attention to the manufacturer's characteristic curves and check air consumption at the planned speeds to dimension pressure supply requirements.