Operating synchronous motors with sensorless speed monitor DN3PD2

When using the DN3PD2 modules in combination with synchronous motors a separate validation must be carried out!

Under what conditions is the use of DN3PD2 modules in combination with synchronous motors permitted?

The operation of the sensorless speed monitor in combination with a synchronous motor is permitted without any hesitation provided:

  • operation is limited to max. 480V AC.
  • The measurement sensitivity of the module is set to mode 4.

    (The devices are delivered with mode 4 by default since August 1st, 2021)

When will a seperate validation become necessary?

Before using a DN3PD2 in combination with a synchronous motor, the function must be checked under the following conditions.

  • The points mentioned in the previous section could not be met.
  • Frequencies below 2.5 Hz are monitored.

How is the separate validation to be carried out?

To do this, proceed as follows:

  • Switch on the driveline to be monitored.
  • Check that the speed monitor is ready for operation (LED OK lights up green).
  • The SPEED LED uses a green signal to indicate that the frequencies at the drive are within the set limits.
  • The release/enable contacts (13-14 / 23-24) of the device are closed.
  • Now run the drive into a non-approved frequency range so that the device triggers.
  • The release contacts (13-14 / 23-24) of the device should now be open. 
  • Then disconnect phase W from the device. 
  • Check whether the release contacts (13-14 / 23-24) are still open.

Validation successfull?

The test was successful if the release contacts were still open with an impermissible frequency and phase W being withdrawn.

Your combination is now validated separately. The device can be operated in the tested configuration.

A validation using an identical drive train is sufficient as a reference.

A different parameterization or varying cable length is not decisive for the result of this separate validation.

What, if my device is already in operation?

To ensure the desired function, the described validation must be performed subsequently on each machine as part of a machine service.

What, if the validation failed?

If the separate validation failed, please get in touch with our Support-Team:
+49 7022 9517 1