n b2-13: Short Circuit Brake Time at StopThe Short Circuit Braking described for parameter b2-12 can also be applied at the end of deceleration to completely stop highinertia loads. Short Circuit Braking is initiated for the time set in b2-13 when the output frequency falls below the higher ofthe values b1-02 and E1-09. Disabled when set to 0.00 s.No. Name Setting Range Defaultb2-13 Short Circuit Brake Time at Stop 0.00 to 25.50 s 0.50 sn b2-18: Short Circuit Braking CurrentSets the current level for Short Circuit Braking operation as a percentage of the motor rated current. The Short Circuit Brakingcurrent cannot be higher than 120%, although a higher current level can be set using b2-18.No. Name Setting Range Defaultb2-18 Short Circuit Braking Current 0.0 to 200.0% 100.0%u b3: Speed SearchThe Speed Search function allows the drive to detect the speed of a rotating motor shaft that is driven by external forces andstart the motor operation directly from the detected speed without first stopping the machine.Example: When a momentary loss of power occurs, the drive output shuts off and the motor coasts. When power returns, thedrive can find the speed of the coasting motor and restart it directly.Enabling Speed Search for PM motors only requires setting parameter b3-01 to 1.The drive offers current detection and speed estimation Speed Search for induction motors. Parameter b3-24 selects the speedsearch method for induction motors. Both methods and relevant parameters are explained below.n Current Detection Speed Search (b3-24 = 0)Current Detection Speed Search detects the motor speed by looking at motor current in IM motors. When Speed Search isstarted it reduces the output frequency starting from either the maximum output frequency or the frequency reference whileincreasing the output voltage using the time set in parameter L2-04. As long as the current is higher than the level set to b3-02,the output frequency is lowered using the time constant set to b3-03. If the output current falls below b3-02, the drive assumesthat the output frequency and motor speed are the same and accelerates or decelerates to the frequency reference.Be aware that sudden acceleration may occur when using this method of Speed Search with relatively light loads.Figure 1.10 illustrates Current Detection Speed Search operation after a momentary power loss (L2-01 must be set to 1 or 2):AC powersupplyOutputfrequencyOutputcurrentOFFONOutput frequency beforemomentary power lossSelectedfrequencyreferenceMin. Baseblock Time (L2-03)Decel timeset to b3-03 Waits for twiceas long as L2-04Speed Search operationcurrent set to b3-02b3-05Figure 1.10 Current Detection Speed Search after Power LossNote: After power is restored, the drive waits until the time set to b3-05 has passed before performing Speed Search. Thereby the Speed Searchmay start not at the end of L2-03 but even later.When Speed Search is applied automatically with the Run command, the drive waits for the minimum baseblock time set toL2-03 before starting Speed Search. If L2-03 is lower than the time set to parameter b3-05, then b3-05 is used as the wait time.1.2 b: ApplicationYASKAWA SIEP YAIZ1U 03B YASKAWA AC Drive – Z1000 Programming Manual 311 Parameter Details
