friction clutches - Arten Freios e Embreagens Industriais

Table of ContentsSensor MountingMounting dimensions for the five framesizes are given on previous pages.Sensors may be mounted at any angle(see Figures A-D).All sensors include a 16 ft. (5M) cablewhich may be extended with 18 AWG 4conductor shielded cable to as long as500 ft. (152M). Presized, Extension Cablesare also available. (see Page 298).Web ProductsMB SERIES TENSION SENSORSFigure A B C DTENSION CONTROLS ◗All sensors must be mounted accordingto the following guidelines:1. Flatness must be 0.002” (0.05 mm) over thelength of the sensor. This can be achievedby milling of the mounting surface.NOTE: Any shimming required for sensorroll leveling must be done between sensorand pillow block. Never shim betweensensor and sensor mounting surface.2. Sensor roll span must equal sensorspan. This is achieved by securing thesensor to the mounting surface, then thepillow block bearings to the sensors, andfinally the bearings to the sensor roll shaft(see Fig. E).3. When sensors are mounted to a base ofmaterial different than that of the sensorroll, i.e. aluminum roll, steel mounting base;secure only one pillow block bearing to theroll shaft. This will allow for different ratesof thermal expansion (see Fig. E).4. Mounting surfaces must be parallel.Self centering pillow block bearings arerequired to take up any variations inparallelism (see Fig. F).Figure EFigure FFigure GMB IIFigure HMB 25NOTE: Noncompliance with these conditionswill induce heavy side loads withinthe sensor. This will cause hysteresis, andthe sensor will measure mechanicalresistance rather than tension load.MB 05, MB II and MB 25 onlyMB05 is normally mounted using the sidemounting plate and cap screws providedwith the unit.MB II and MB 25 may be mounted oncustomer supplied wall mounting brackets .(See figures G & H).All three sizes may be mounted for eithernormal or reverse web wrap. The tensioninduced force (F) is calculated the same inboth cases and the allowable load range persensor (see chart page 3) does not change.MB 33 and MB 41Due to the high forces generated by websneeding MB 33 and 41 load cells, reversewrap is not recommended.Due to the high forces generated, side wallmounting is not recommended.Contact Nexen or your Nexen distributoror representative if you have any questionabout sensor sizing.InstallationSensor LocationCorrect LocationFigure (3) illustrates correct sensorlocation for winding or unwinding control.One transport roll (A) located between thesensors and roll stand serves to fix theweb angle over the sensor roll.Figure (4) illustrates angular changes asthe roll changes diameter during processing.Incorrect LocationThese angular changes will cause incorrectreadings from the Tension sensors and mustbe avoided by use of roll (A) (see Fig. 3).Figure (5) illustrates a common mistake insensor mounting. In this configuration, the“S” wrap drive will effectively isolate tensioninto two zones, T 1 and T 2 . A nip roll at thesame position would provide the sameisolation. The roll stand brake or clutchcan only control tension in T 1 zone. Sincethe sensors are mounted in the T 2 zone,they can not sense any tension changescaused by the roll stand and can not beused for closed loop control. The sensorsmust be moved to position “A” for propercontrol of the roll stand and T 1 tension.Contact Nexen or your Nexen distributoror representative if you have any questionabout sensor sizing.301