The Wheel Diameter Measuring Device MDD measures wheel diameters quickly and accurately. No need to remove wheelsets, MDD fits under locomotives, wagons and cars. The device can be used in field conditions as well as in workshops.

A new version of the wheel diameter measuring device MDD will be launched to the market in the near future. It will replace the current MDD, which has been manufactured and marketed since 1995. The new MDD includes several advanced features for ease of use and accuracy. It enables more accurate measurement results by correcting linear errors of the position transducer. The power source, rechargeable lithium-ion battery, allows the device to be used for more than a week without charging.

The new MDD will be manufactured in two different versions. The simpler version only displays the measurement results. The extended version has a wireless connection, allowing measurements to be made flexibly on a tablet, mobile phone or PC according to the visual bike map with time and date information.

Operation

MDD measures the wheel diameter using a three-point measurement. Two of the points being established by fixed hard metal rollers, the third point is measured with an inductive position transducer.

The new version of MDD can be set for reading the measurement from either side of the wheel or on the external user device. The value of each measurement is stored either using the external device or via the MDD save button. A practically unlimited number of measurements can be stored on the external device (e.g. tablet). In addition to the wheel diameter, it is possible to include the date and time of the measurement and possibly predefined data according to the visual wheel map or related listing.

A useful new feature of MDD is the measurement of the wheel diameter difference. Taking two adjacent measurements of wheels on the same axle provides information about the balance of the wheels.

Another new built-in feature is bearing failure notification. Measuring the wheel surface at several points should give exactly the same value. In the case of a bearing failure, the readings will have different values.

This is given as a deviation value in connection with a bearing fault alarm.

A unique property of MDD is the temperature compensation of measurement results, which is based on carefully selected materials and corresponding expansion coefficients.

Measurement Ranges and Calibration

MDD is manufactured in two types: MDD-350 for 1255-750 mm wheels and MDD-315 for 1050- 590 mm wheels.

The standard distance between the reference plane, i.e. wheel inner side and the taping line, is 70 mm. Devices with different reference distances can be delivered at request.

In the new MDD all setting parameters, such as device-specific calibration parameters and language versions together with the serial number, will be stored in the MDD’s internal memory.

Accuracy

The reading accuracy is 0.1 mm. The accuracy of the repeatability remains at 0.1 mm over a long period of time. The true measurement accuracy is in the range of 0.2 mm with digital linearity correction. Requirement is that the wheel is round and has good reference plane and running surface.

Dimensions

Length: MDD-350 380 mm, MDD-315 345 mm.

Height from the tread level: 151 mm.

Depth: 106 mm.

Weight: measuring unit 0.9 kg, total weight 5.9 kg

Operating temperature -15 ^oC...+45 ^oC.

The new construction is well sealed to protect it from dust, dirt and moisture but not absolute waterproof.

Design and technical data are subject to change.

Contact:

M.D. Measuring Device Ky

Address: Kuutamokatu 6 B 28, 02210 Espoo, Finland

Tel: +358500414823

Email: md@md.inet.fi