Frequency Inverter DF51... - Moeller.com.tr

04/07 AWB8230-1541GB BrakingBrakingBraking is the slowing down of a drive system to standstill or aspecific lower speed within a specified time. Braking can takeplace mechanically (using a friction brake) or electrically (DCbraking or braking choppers).The DF51 devices allow the following braking methods:• Actuation of an external mechanical holding brake throughrelay K1 (a section “Signalling relay K1 (terminals K11, K12,K14)”, page 109) or a digital output (a section“Parameterizable digital outputs”, page 107).• DC braking: applying direct current to the three-phase motor• Regenerative brakingDC braking (DCB)To activate DC braking for decelerating the motor, do thefollowing:• apply a stop signal (PNU A051 = 01) or• activate the digital input configured as DCB.By applying a pulsed DC voltage to the motor stator, a brakingtorque is induced in the rotor and acts against the rotation of themotor. With DC braking, a high level of stopping and positioningaccuracy can be achieved.Under PNU A051, define whether DC braking is to be activatedautomatically when the frequency set under PNU A052 is reachedand/or when the DCB input is activated.Under PNU A052 enter the frequency at which DC braking isactivated when PNU A051 is 00.Under PNU A053, enter the waiting time which is to elapse beforeDC braking be<strong>com</strong>es active after activation of the DCB input orwhen the set startup frequency is reached.Under PNU A054 enter the braking torque between 0 and 100 %.In PNU A055, enter the DC braking duration.Under PNU A056 specify the braking behaviour when the DCBinput is active:• 00: DC braking starts when the DCB input is activated and endsonly when the time defined under PNU A055 has expired.• 01: Braking starts as soon as the DB input is active and endswhen the DCB input is deactivated.DCBREVFWD5 2 1P24DC braking can also be activated before motor acceleration, forexample in lifting and conveying applications (releasing themechanical holding brake) or with drives which are operated usingprocess variables, such as fans, pumps and <strong>com</strong>pressors.Figure 132:Digital input 1 configured as FWD (start/stopclockwise rotating field), input 2 as REV (start/stopanticlockwise rotating field) and input 5 as DCB (DCbraking).h Attention!DC braking results in additional heating of the motor. Youshould therefore configure the braking torque(PNU A054) as low and the braking duration (PNU A055)as short as possible.FWD/REVaaDCBDCBDCBtf Of Of OFigure 133: Function chart for DCB (DC braking)f o : Output frequencyt: Waiting time PNU A053a Start signal through keypadX Configure one of the digital inputs 1 to 5 as DCB by entering thevalue 07 under the corresponding PNU (C001 to C005).X In PNU A053, enter a delay time t (a fig. 133) from 0 to 5.0s, which is to expire before DC braking takes effect afteractivation of the DCB input.X Under PNU A054, set a braking force between 0 % and 100 %.121