Torque

  • Menu: 4.2.11-1.3

Description

Torque setpoint.

If the counter torque of the drive is too small or becomes 0 due to breakage of the drive shaft, the drive would permanently accelerate with the specified torque setpoint. The drive accelerates up to the specified positive and negative speed limit and then continues in a speed-controlled manner. The torque is limited to maintain the speed limit. Near the speed limit, the torque is continuously reduced along a straight line.

Q1 to Q4

Quadrant

M1

Maximum positive torque (parameter group Profile value connection)

M2

Maximum negative torque (parameter group Profile value connection)

n1

Maximum positive speed (parameter group Profile value connection)

n2

Maximum negative speed (parameter group Profile value connection)

INFORMATION

In generator mode (quadrants Q2 and Q4), the application limit of the speed might be violated.

The gradient of the straight line is calculated according to the following formula:

ΔM

Difference of the torque limits

[ΔM] = Nm in relation to the torque at the motor shaft

Δn

Width of the transition area

[Δn] = s-1 in relation to the speed at the motor shaft

Jtot

Total moment of inertia of the drive (sum of the mass moments of inertia of the motor, brake, gear unit and load)

The mass moments of inertia can be determined from the parameters in the parameter group Drive trains > Optimization DT. > Set load moment of inertia.

[Jtot] = kgm2 in relation to the speed at the motor shaft

KP

P gain of the speed controller

The P gain is displayed under the advanced settings in the parameter group Drive trains > Optimization DT. > Set controller dynamics.

[KP] = s-1

For speed limitation to work properly, the speed controller must be parameterized correctly in the drive functions FCB 07 Torque control and FCB 08 Interpolated torque control. Otherwise, the torque might be unnecessarily limited even at low speeds.

The following parameters are set:

Parameter

Meaning

Source

Specifies from which source the setpoint is retrieved.

PO data format

Length of the process output data word

Value

Current torque setpoint that is used in the following drive functions:

  • FB 07 Torque control
  • FCB 08 Interpolated torque control

If the Local value setting has been specified for the Source parameter, the user can specify the value locally. The locally specified setpoint can be useful, for example, in the startup phase to specifically specify setpoints for the inverter without a higher-level controller that has already been started up. The local value is stored in a non-volatile memory.