Yaskawa AC Drive-P1000 Industrial Fan User Manual

Page 248

L3-04: Stall Prevention Selection during Deceleration

Stall Prevention during deceleration controls the deceleration based on the DC bus voltage and prevents an overvoltage fault

caused by high inertia or rapid deceleration.

No.

Name

Setting Range

Default

L3-04

Stall Prevention Selection During Deceleration

0 to 5

<1>

<1> Setting 3 is not available in models 4A0930 or 4A1200.

Setting 0: Disabled

The drive decelerates according to the set deceleration time. With high inertia loads or rapid deceleration, an overvoltage fault

may occur. If an overvoltage fault occurs, use dynamic braking options or switch to another L3-04 selection.

Setting 1: General-purpose Stall Prevention

The drive tries to decelerate within the set deceleration time. The drive pauses deceleration when the DC bus voltage exceeds

the Stall Prevention level and then continues deceleration when the DC bus voltage drops below that level. Stall Prevention

may be triggered repeatedly to avoid an overvoltage fault. The DC bus voltage level for Stall Prevention depends on the input

voltage setting E1-01.

Drive Input Voltage

Stall Prevention Level during Deceleration

200 V Class

377 Vdc

400 V Class

754 Vdc

600 V Class

1084 Vdc

Note:

1. Do not use this setting in combination with a Dynamic Braking Resistor or other dynamic braking options. If Stall Prevention during

deceleration is enabled, it will be triggered before the braking resistor option can operate.

2. This method may lengthen the total deceleration time compared to the set value. If this is not appropriate for the application consider

using a dynamic braking option.

Figure 5.79

illustrates the function of Stall Prevention during deceleration.

Output Frequency

Deceleration characteristics
when Stall Prevention was
triggered during deceleration

Time

specified deceleration time

Figure 5.79 Stall Prevention During Deceleration

Setting 2: Intelligent Stall Prevention

The drive adjusts the deceleration rate so the DC bus voltage is kept at the level set to parameter L3-17. This produces the

shortest possible deceleration time while protecting the motor from stalling. The selected deceleration time is disregarded and

the achievable deceleration time cannot be smaller than 1/10 of the set deceleration time.
This function uses the following parameters for adjusting the deceleration rate:
• DC bus voltage gain (L3-20)
• Deceleration rate calculations gain (L3-21)
• Inertia calculations for motor acceleration time (L3-24)
• Load inertia ratio (L3-25)

Note:

The deceleration time is not constant. Do not use Intelligent Stall Prevention in applications where stopping accuracy is a concern. Use

dynamic braking options instead.

Setting 3: Stall Prevention with dynamic braking option

Enables the Stall Prevention function while using a dynamic braking resistor.

Setting 4: Overexcitation Deceleration 1

Overexcitation Deceleration 1 (increasing the motor flux) is faster than deceleration with no Stall Prevention (L3-04 = 0).

Setting 4 changes the selected decel time and functions to provide protection from an overvoltage trip.

Refer to Overexcitation

Deceleration (Induction Motors) on page 264

for details.

5.8 L: Protection Functions