P4-07 Max. motor torque limit

Setting range: P4-08 – 200 – 500%

This parameter is used to set the upper torque limit. The limit value source is specified with parameter P4-06.

Example 1: Asynchronous motors in V/f control

In V/f control, the percentage apparent output current is limited, depending on P1-08.

Example 2: Asynchronous motors in VFC control

Setting and verifying the torque limit (P4-07) for asynchronous motors:

Data of the asynchronous motor:

P_n = 1.1 kW, I_n = I_s = 2.4 A, n_n = 1420 min^-1, cos φ = 0.79

The torque is limited to M_max = 8.1 Nm.

For verification of the torque-generating inverter current in P0-15:

I_q = cos(φ) × I_s = cos(0.79) × 2.4 A = 1.89 A

For a calculated torque limit of 109.45%, P0-15 should display the following

.

Example 3: Synchronous motors in PMVC control

Setting and verifying the torque limit (P4-07) for synchronous motors:

The torque is limited to M_max = 1.6 Nm.

Data of the synchronous motor: I₀ = 1.5 A, M₀ = 0.8 Nm

For verification of the torque-generating inverter current in P0-15:

I_d = 0, standard for synchronous motors with vector control, this results in I_q ≈ M.

For a calculated torque limit of 200%, P0-15 should display the following:

P0-15 = I₀ × 200% = 3 A