Radio-based vibration monitor checks machine conditions

SKF has developed a radio-based system for monitoring the condition of rotating machines. The company claims that the wireless system will boost productivity, especially for equipment located in inaccessible locations, or for applications where it would be difficult to install cables.

The equipment can be moved quickly and easily from one machine to another, making it suitable for on-line trouble-shooting. Using appropriate software, the vibration data can be analysed to identify bearing or gear mesh problems, machinery faults, and poor lubrication conditions.

At the heart of the system is a vibration sensor linked to a battery-powered processor and transmitter. The sensor converts vibrations from the machine into an electric signal which is transmitted to a base station linked to a PC which can process and analyse it further. The system can monitor trends or provide in-depth analysis using the full vibration spectrum.

As well as the vibration sensor inputs, the sensor boxes have tachometer inputs for speed and binary trigger inputs to synchronise measurements with machine events. Each sensor is connected by a short cable to the radio module.

The radio, which has a 100m transmission range, operates on the 2.4GHz band, which is license-free worldwide. One base station can accommodate up to 32 wireless sensors but more base stations can be added if larger networks are needed. The radio modules use frequency hopping and automatic error correction to ensure reliable communications. Depending on monitoring intervals, the transmitter batteries will last between 6-9 months.

The system can be used on almost any form of rotating equipment but is being targeted, in particular, at applications in the machine tool, pulp and paper, and steel-making industries where access for conventional condition monitoring equipment is awkward or potentially dangerous. The wireless system is available as a stand-alone package or as a complement to a cable-based on-line system.