Parameter Details1111.9 L: Protection FunctionYASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual 847Table 11.57 Decel Stall Prevention LevelDrive Input Voltage Decel Stall Prevention Level200 V class 377 V400 V class 754 VThe following figure illustrates the function of Stall Prevention during deceleration.Figure 11.131 Decel Stall Prevention Operation2 : Automatic Decel ReductionThe drive adjusts the deceleration rate so the DC bus voltage is kept at the level set to L3-17 [DC Bus Reg Level].This produces the shortest possible deceleration time while protecting the motor from stalling. The selecteddeceleration time is disregarded and the achievable deceleration time cannot be smaller than 1/10 of the setdeceleration time.This function uses the following parameters for adjusting the deceleration rate:• L3-20 [DC Bus Voltage Adjustment Gain]• L3-21 [Accel/Decel Rate Calculate Gain]• L3-24 [Motor Accel Time for Inertia Cal]• L3-25 [Load Inertia Ratio]Note:The deceleration time is not constant. Use dynamic braking options instead and set L3-04 t= 0 in applications where stopping accuracyis a concern. Set L3-04 = 3 if an ov occurs.3 : General Purpose w/ DB resistorThis setting requires a dynamic braking resistor. Enables the Stall Prevention function while using a dynamicbraking resistor.4 : Overexcitation/High FluxEnables Overexcitation Deceleration 1. Enables deceleration times shorter than that when L3-04 = 0.Note:• A long overexcitation time and frequent repetitions of deceleration can trigger oL1 [Motor Overload]. If an oL1 is detected, eithershorten the deceleration time or install a braking resistor to the drive.• The deceleration time during Overexcitation Deceleration varies depending on the motor characteristics and machine inertia. Adjust thelevels set by n3-13 [Overexcitation Deceleration Gain] and n3-23 [Overexcitation Operation Select]. Refer to “n3: High Slip Braking(HSB), Overexcitation Deceleration” for details.5 : Overexcitation/High Flux 2Enables Overexcitation/High Flux 2. This function shortens the achievable deceleration time more than by usingOverexcitation/High Flux.The drive slows down the motor while trying to maintain the DC bus voltage at the level set to L3-17.Lower the values set in n3-13 and n3-21 if an oL1 is detected. Increase the value set in C1-02, C1-04, C1-06, andC1-08 [Deceleration Time] if an ov is detected.Note:• While Overexcitation/High Flux 2 is operating, both Hunting Prevention in V/f Control and Speed Control using torque limit in OLVControl are disabled.• Refer to “n3: High Slip Braking (HSB), Overexcitation Deceleration” for details.
