Each Mentor MP series digital DC electric drive already has a built-in field controller by default, the current value of which depends on the selected dimension (standard size).
The value of the excitation circuit current of the built-in field controller
- dimensions 1A, 1B (from Mentor MP25A4R to MP210A4R): 8A;
- габарит 2A, 2B, 2C, 2D (от Mentor MP350A4R до MP1850A4R): 20А.
To control DC electric machines with excitation currents exceeding the above values, it is recommended to use external FXMP25 field controllers (operating current 25A), at high values, Mentor MP45A4, MP75A4, MP105A4 non-reversible drives are used …
The FMXP module can be used in conjunction with the Mentor II series electronic speed controller Control Techniques (Mentor 2 - discontinued).
External excitation modules are connected to the converter via the RJ45 port, the operation mode of the electric drive with an external field controller is configured using STSoft software or using the control panel. The process of setting up this mode and the connection diagram of the FMXP25 module is shown at the bottom of this section.
Reasons for using external field controllers for excitation circuits
- The rated current of the field winding is greater than the rated current of the integrated controller. It is applicable when upgrading control circuits of electric drives of type "G – D" (Generator – Motor), when the former collector motors (DC electric motor) are left;
- More dynamic control of the excitation winding is needed. Applicable for electric drives of machine tools and electric motors with a large field winding time constant;
- implementation of reverse rotation of an electric motor using a 2-quadrant electric drive. It is applicable for control systems with low dynamics, a significant reduction in the cost of equipment.
Recommendations for setting up an external FXMP25 field controller
Input of DC motor parameters and selection of field control mode
- enter the parameter Pr 70 – rated motor current in Amperes.
- enter parameter Pr 73 – rated motor voltage in Volts.
- select the Pr 78 field control mode: the value of the parameter Pr 78=St.H (4) – half bridge control; the value of the parameter Pr 78=St.F (5) – full bridge control.
- reset the controller by holding down the Mode button for at least 2 seconds.
Automatic configuration/optimization of the field controller
Performing auto-tuning (optimization) of the excitation circuit allows you to automatically determine the proportional Pr 71 and integral Pr 72 gain coefficients of the field regulator.
- set the Pr 12 parameter (Auto-tune)=ON (1);
- set the Pr 77 parameter (Field Management Permission)=ON (1).
If field attenuation is required, then adjust the following parameters
- enter the parameter Pr 59 – the required value of the motor armature voltage from which the field attenuation mode should be activated;
- In order to prevent excessive attenuation of the field, enter the value of the minimum flow/limitation of the excitation voltage in the parameter Pr 69, in % of the nominal value.
Activating an external field controller
- set the parameter Pr 77=ON (1) - controller operation permission;
- set the parameter Pr 80=OFF (0).
The FXMP25 external field controller is ready for the robot as part of the Mentor MP thyristor electric drive.
Functional controls, terminals of the FXMP25 controller, typical connection diagram
