152 • Vacon apfiff09 marineTel. +35867.7.2 Closed loop settingsP2.7.2.1 Magnetizing current at start ID627Defines the current that is applied to the motor when the start command is given inclosed loop control. At start this parameter is used together withMagnetizing time atstart to decrease the time when the motor is able to produce nominal torque. In closedloop control output frequency is not forced to zero while magnetization current is appliedto motor.P2.7.2.2 Magnetizing time at start ID628Defines the time for how long magnetization current is applied to motor at start.Magnetizing current at start is used to shorten the time when flux is at nominal level.This will improve the torque performance at start. The time needed depends on themotor size, value varying between 100 ms to 3 second. The bigger the motor the moretime it needs. Set this time so that the rotor flux is more than 90 % before speed isreleased (Start Zero Speed Time ID615) or mechanical brake is released.P2.7.2.3 Flux reference ID1250Reference value for rotor flux. Rotor flux can be reduced by changing the magnetizationcurrent. This, however, also affects the motor model making the torque calculations alittle less accurate. When using this parameter the motor model can compensate theeffect of the different magnetization current in torque calculations.[𝐹𝑊]𝑅𝑜𝑡𝑜𝑟𝐹𝑙𝑢𝑥 = (𝑓(𝑀𝑜𝑡𝑜𝑟𝑁𝑜𝑚𝐹𝑟𝑒𝑞)𝑓(𝑂𝑢𝑡) )2 𝑤ℎ𝑒𝑛 𝑓(𝑂𝑢𝑡) > 𝑓(𝑀𝑜𝑡𝑜𝑟𝑁𝑜𝑚𝐹𝑟𝑒𝑞)FluxFluxFn 2xFn50 %25 %75 %Output frequencyP2.7.2.4 Flux Off Delay ID1402The Flux off delay function will keep the motor magnetized after a stop command thusmaking the next start faster because flux is already available in the motor. The functionis used e.g. in a system where several repeated starts are made in short cycles. The fluxlevel can be adjusted by parameterStop State Flux.0 = Flux is not maintained in the motor>0 = Flux off delay in seconds.-1 = Flux is maintained indefinitely in the motor
