Melectric System has developed a plug-and-play measuring flange that collects data on speed, torque and temperature … and it works wirelessly.
Measuring pto speeds and torques directly on the shaft is not only an interesting prospect for our machine tests, but it should also be of potential interest to many implement manufacturers and workshops. True, this has been possible for some time, but the devices usually need a cable to provide a power supply and transmit the data. This is not only time-consuming, but it can also quickly lead to some significant problems – spinning driveshafts and wiring…
Non-contact measuring
The new measuring system developed by Melectric works on the fundamental principle of magnetoelasticity, which means that the magnetic field of ferromagnetic material changes when exposed to forces. The changes of the magnetic field are measured by non-contact sensors and then evaluated by the electronic system.
According to Melectric, the basic principle facilitates precise measurements across a large torque range – in fact up to +/-2,500 or +/-5,000Nm depending on the flange. The electronic system can record further parameters such as temperature and speed. The manufacturer specifies a measuring accuracy of +/-0.2% relative to the max value (FS). Melectric also points out that the signal bandwidth is 1 to 200Hz, but that it also possible to increase it to 1.2kHz or up to 25kHz on request.
All the measuring technology is housed in the compact flange fitting that is less than 5cm long and IP67 rated. Hence, water ingress, strong vibrations and stone chips shouldn’t be a problem. And thanks to the DIN- and SAE-compliant flanges for drive- shafts, it is easy to thread it onto the stub and driveshaft. The pto stub then sits 18cm further to the rear.
App for recording
To record the measurements, you need Melectric’s in-house developed app, which is free though currently only available for Android devices. Downloading and setting it up on a smartphone is straightforward. The connection to the measuring unit is done via Bluetooth.
Initially we struggled with the compact unit occasionally disconnecting, but an update from Melectric sorted the problem so that, if your phone goes into standby, it doesn’t cause any hiccups. However, if you move your phone outside of the Bluetooth range, which is about 8 to 10m, the data transfer and recording is paused. Recording only continues once you are reconnected.
Another neat option for storing the data for long-term measurements, for example, is the Smart Mini Gateway. This requires a 12V power supply, but then it does connect automatically via Bluetooth to store the data or transfer it to an existing CANbus system. There is also the handy option of attaching external antennas to optimise the range or to output the data via LTE radio.
After installing the software, we connected the gateway to a laptop via an Ethernet connection. However, we couldn’t find a display that was reading out the live data. Instead, the collected data was stored in a specific format to the gateway so that you have to convert them into a CSV file using the software. You also get an Excel file when you record the data with the app. In our case, the software used a dot as a separator, which we had to replace by a comma before we could edit in Excel. Details like this have been addressed in the meantime, says Melectric.
Convincing results
Melectric claims an ‘easy-to-use, robust system for torque and power measurements for analysis, monitoring and developing applications’. We can confirm this by and large after using the new measuring flange (calibrated to DIN 51309).
Its compact build and wireless use were particularly convincing. We would also like to see an app for IOS so that Apple phones and tablets can also be used. Prices start at €2,550 for the measuring flange (up to 25kNm) and €980 for the gateway.
Hubert Wilmer
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