Magtrol WB Series User Manual

Contents

Magtrol WB Series User Manual Manual pdf 59 page image

49Magtrol WB/PB DynamometersChapter 2 – Installation / Mounting2.4 MEASURING RANGEAs with most transducers, dynamometers should be operated in the upper part of their measuringrange, between 10% and 100% of their rating.2.5 DRAG TORQUEMagtrol dynamometers are characterized by a low drag torque: approximately 1% of the rated torquefor WB Series Dynamometers and approximately 2% for PB Series Dynamometers. Refer to thecorresponding data sheets (see Section 1.2) for the maximum drag torque values of each model.Drag torque (which is measured by the dynamometer) is generated by friction originating from thebearings, the contact between the powder and the rotor unit in magnetic powder brakes, as well asall other mechanical contacts.2.6 TOLERATED RADIAL AND AXIAL FORCESNote: Any radial or axial force exercised on a dynamometer causespremature wear of the bearings, as well as an increase of the dragtorque.The following table shows the maximum axial and radial forces the WB/PB Series Dynamometercan support without being damaged:Series Standard version High-speed version (HS)*Faxial max [N] Fradial max [N] Faxial max [N] F radial max [N]WB/PB 2.7 20 5 4 2.5WB/PB 43 40 30 8 15WB/PB 65 200 60 40 30WB/PB 115 300 200 60 100WB/PB 15 N/A N/A N/A N/A* Only Eddy-current (WB) Dynamometers have, as an option, a high-speed version.For WB-HS Dynamometers, the limit is lower in order to protect the high-performance bearings.Magtrol offers, for the same reason, a specially adapted high-speed coupling.By applying a radial or axial force on the dynamometer, the bearings are subjected to differentstresses. This hinders them from rotating freely and generates torque on the measuring line.The side load of the measuring line is detected by the dynamometer cell. This is not an offset but a realtorque, normally measured. Thus, the zero on the electronics must not be set when the dynamometeris mechanically coupled.