An example for the parameterization to be applied on an FR-CS80 Inverter for a constant torque application. 

Parameterization of VFD for Constant Torque applications

Apart from variable torque applications (flow rate control, pressure control, and other energy savings related to applications),  there is also a constant torque type of applications.

The following parameters apply;

For constant torque applications: (Like conveyors, cranes, crushers, gates)

Motor Nameplate

As a prerequisite for  the selection and parameterization of a VFD – there are two requirements:

  1. The application details
  2. The motor nameplate details

For this example we will setup the VFD for an Auger application (constant Torque) for a motor with the following motor nameplate details; 

The Parameterization settings

The following are the minimum parameterization to be applied for a minimum configuration setup.

These are collectively called – Basic Parameterization:

                Pr.1 = Maximum Frequency = 50Hz

                Pr.2 = Minimum Frequency = 0Hz

                Pr.3 = Base Frequency – Motor Nameplate Frequency = 50Hz

               Pr.9 = Electronic Thermal O\L Relay (Rated Inverter Output Current) Motor Name Plate Current = 3.61A

                                Aka the motor FLA (Full Load Amps) – Current

                Pr.14 = Load Pattern Selection = 0 (constant torque)

                             (some drives do not have this setting)                    

                Pr.19 = Voltage measured by the multi-meter – going into the motor = 220Vac

Pr.29 = Acceleration/deceleration pattern selection = 0

                Pr.80 = Motor capacity = 0.75kW

                                Found on the motor nameplate

                Pr.81 = number of motor poles (found on motor nameplate) = usually 4

                                (some drives do not have this setting)    

                Pr.83 = Rated motor voltage (found on motor nameplate) = usually corresponding to Pr.19

                               (some drives do not have this setting)    

                Pr.84 = Rated Motor Frequency (found on the motor nameplate) = usually corresponding to Pr.3 

Then if auto-tuning is required:

                Pr.96 = Auto-tuning setting/setting

Some additional Notes

Note also that:

  • Some of these parameters will not be available in the FR-CS80, FR-D700, and FR-E700  series drives, and will only be available in the specialized drives FR-F800 and FR-A800.

                                                e.g.   Pr.14 – Load Pattern Selection

                                                           Pr.81 – Number of motor poles

                                                           PR.83 – Rated motor voltage

                                                If these parameters are missing – they don’t have to be set.

  • Auto Tuning is highly recommended – prior to concluding the basic parameterization. (the basic parameterization is a prerequisite for VFD utilization.

                Two types of Auto tuning: Online and Offline. (Pr.96 = Auto-tuning setting/setting)

                                Online: When the motor can be disconnected from the load. (Shaft will rotate) (more accurate) (recommended)

                                Offline: When the motor cannot be disconnected from the load. Shaft won’t rotate (less accurate)

Reference and Information Resources

The following Reference information can be used for detailed information on this topic being covered.