Series J Shaft Mounted Gearbox - Benzlers

SERIES JSELECTION PROCEDUREDefinition of service factorThe torque ratings apply to service factor fb = 1,0.The service factor fb = 1,0 gives continual operation 4to 8 hours a day at a uniform load without shocks andwith 10 to 200 starts an hour. The moment of inertia ofthe driven machines is less than 20 % of the electricmotor inertia and occasional peak torque may notexceed 1,8 times the torque rating. For other runningconditions compensate with service factors accordingto tables.DefinitionsP e= Demand of power from driven machine (kW)T e= Demand of torque from driven machine (Nm)n e= Speed on driven machine (min -1)T emax= Max peak torque from driven machine (Nm)T2 = Max allowed torque at service factor fb =1,0Thermal ratingThermal rating is the power in kW (without servicefactor) that the gear unit can transmit at continuousoperation in 1 hour or more without getting overheated.Control of thermal rating is essential because if theservice generates more heat than it can emit, severedamage may occur.Thermal rating does not need to be controlled if theduty time is less than 1 hour.When the duty time is longer than 1 hour the gear unitand cooling method must be selected so that the drivetransmission has enough thermal rating.In the tables the thermal rating Pt is given in thefollowing conditions:- 25 °C ambient temperature- 0 to 750 m altitude above sea level- Ambient air velocity between 1,4 and 3,7 m/s(sheltered outdoor space)- Continuous operationFor sizes J100 to J190 standardized solutions forcooling of the gears are available. An electric fancan be mounted on the gear. The gear may also beprovided with a water-based oil cooler (contact ourApplication Engineers for selection of correct size).1) At V-belt drive when the motor is placedbeside the gear, check the operationaccording to the diagram.Mechanical RatingStartDetermine the demand of power (Pe kW) or torque (T eNm)and speed (n emin -1 ) to the driven machine by calculation ormeasuringBased on type of load / driven machine, operating hours aday and number of starts an hour select service factor (fb)according to table 1 and table 2Select Series J gear from power rating tables on pages 22 - 52.Select the mechanical rating:T2 > fb x T eNm1)Shock load ?Yes T emax< 1,8 x T2NoThermal RatingYesNoUse a larger gearsize or contactour ApplicationEngineersSelect ambient temperature factor ft according to table 3Select altitude factor fa according to table 4Select ambient air velocity factor fv according to table 5Select operation time factor fu according to table 6Control of thermal rating without extra coolingCheck that the thermal rating of the selected gear Pt is biggerthan required thermal rating:Pt ≥ P eft x fa x fv x fuThermal rating Pt for mineral and synthetic oil are in thetables on pages 8 - 13. The values are valid for horizontalapplications. For vertical applications 0,8 x Pt is usedYesYesOrder anelectric fanfrom usNo, extra cooling is neededControl of thermal rating with electric fanCheck that the thermal rating of theselected gear Pt is bigger than requiredthermal rating:Pt ≥ P eft x fa x fuThermal rating Pt for mineral andsynthetic oil with fan cooling are in tableson pages 8 -13. The values are validfor horizontal applications. For verticalapplication 0,8 x Pt is used.No, cooling with fan is not enoughCan a water based oil cooler be used ?YesOrder a waterbasedoil cooler from usNoUse a larger gearsize or contactour ApplicationEngineersSelect accessories (V-belt drive, motor mount, KIBO, backstop)Order gear with accessories according to 20-digit figure code page 5.5