A frequency converter rectifies AC voltage from mains into DC voltage, after which this DC voltage is converted into a AC current with a variable amplitude

and frequency.

The motor is supplied with variable voltage / current and frequency, which enables infinitely variable speed control of three-phased, standard AC motors.

2.8.2. Control Structure

Control structure in open loop and closed loop configurations:

In the configuration shown in the illustration above, par. 1-00 is set to

received and fed through the ramp limitation and speed limitation before being sent to the motor control. The output of the motor control is then limited

by the maximum frequency limit.

Closed loop

Select

[3] in par. 1-00 to use the PID controller for closed loop control of e.g. flow, level or pressure in the controlled application. The PID

parameters are located in par. group 20-**.

2.8.3. Local (Hand On) and Remote (Auto On) Control

The frequency converter can be operated manually via the local control panel (LCP) or remotely via analog and digital inputs and serial bus.

If allowed in par. 0-40, 0-41, 0-42, and 0-43, it is possible to start and stop the frequency converter via the LCP using the [Hand ON] and [Off] keys.

Alarms can be reset via the [RESET] key. After pressing the [Hand On] key, the frequency converter goes into Hand Mode and follows (as default) the

Local reference set by using the LCP arrow keys.

Open loop

[0]. The resulting reference from the reference handling system is

MG.20.N3.02 - VLT

is a registered Danfoss trademark

VLT

AQUA Drive Design Guide

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