LOHER DYNAVERT I Current-Source Inverters

General description

LOHER DYNAVERT I drive units are currentsource DC link inverters that are used to control induction motors. They have a fully controlled B6 bridge circuit on the line side and a B6 inverter circuit on the output side, which utilizes the principle of interphase commutation; this distributes the DC link current from the DC link reactors with a square waveform with frequency f to the motor winding. As a consequence, the motor cable length is almost unlimited.
The power flows from the line supply to the motor for a motoring load. For regenerative operation, the rectifier on the line-side feeds the regenerated energy back into the line supply. This means that from the inherent principle, 4-quadrant operation is possible without requiring any additional measures. 12- and 24-pulse versions further reduce the harmonics fed back into the line supply.
For this reason LOHER DYNAVERT I is the ideal replacement for SIMOVERT A.


Technical data overview

Rated input voltage

Typ. Motor rated power cabinet systems

400 V

15 - 630 kW

500 V

15 - 800 kW

690 V

45 - 5600 kW 

950 V

630 - 6000 kW 

Brief overview

Line supply voltage
+10 %, -15 %:

3~AC 400 ... 1140 V

Line supply cos phi (1):

Depends on the motor

Line supply frequency:

50 Hz, optional 60 Hz

Maximum output frequency:

60 Hz, depends on the motor

Output voltage
(basic fundamental):

3 x 0 ... line supply voltage

Motor cable length
(shielded or non-shielded):

500 m, longer on request

Degree of protection:

IP21, higher degrees of protection optionally available


Explosion protection

  • ATEX-certified for motors located in hazardous zones with Accessory kit S, also with very long motor cable length

Emergency Off

  • The Emergency Off function prevents unexpected starting in compliance with EN60204-1, implemented according to EN954-1, Category 3, respectively SIL2 with Accessory kit S

Power unit

  • 12- and 24-pulse input optional posible. For this reason gi line supply (basic fundamental) of 99,9 % is possible

  • This corresponds to the EMC Directives (EN61800-3 environment 2) as a result of the line filter integrated as standard

  • Low harmonics fed back into the line supply as a result of the integrated line reactor

  • Long motor cable lengths possible inherent to the system

  • Insulation monitoring for IT line supplies for 500 / 690 V drive units as well as ground fault monitoring for TN and TT line supplies integrated in the 400 V drive units

  • Wide supply voltage range

  • Normal fuses can be used for protection (gL characteristic)

Control section

  • High level of personnel and plant protection through protective separation between the analog and digital control peripheral and the power unit according to VDE 0106 / EN50178

Operator control and setting

  • Transparent operator control and setting using a menu-prompted 4-line plain text display with membrane keypad at the drive inverter – or up to 1000 m away in the main control room via RS485

  • Extensive functions using the Windowsbased PC operator control program


  • Communication via a conventional terminal strip with freely-programmable digital and analog inputs / outputs, with
    - parameterizable limit value signals
    - parameterizable timers
    - parameterizable damping elements
    - parameterizable drive inverter behavior when inputs / outputs respond

  • Communication and parameterization via
    - PC using IMS (Inverter Management Software) via RS232 / RS485
    - external operator panel via RS485
    - bus systems such as Profibus DP or Modbus RTU

Drive behavior for LOHER DYNAVERT I

  • Two closed-loop control types for induction motors:
    - Speed control
    - Torque control

  • Full 4-quadrant operation with regenerative braking as standard

The following generally apply

  • Automatic slip compensation

  • Stall protection using current limiting control

  • Flying restart circuit to connect to a rotating motor

Customer benefits

  • Cabinet units in IP21 or higher degrees of protection

  • All of the drive units have their own connection space

  • Compact dimensions

  • Equipped with radio interference suppression

  • Low harmonics fed back into the line supply, mainly on 12- and 24-pulse versions

  • Almost unlimited motor cable lengths possible inherent to the system

  • High overvoltage strength, e.g. load shedding of turboset in power stations

  • Wide supply voltage range

  • Full 4-quadrant operation as standard

  • Same user interface / software as LOHER DYNAVERT T

Typical applications

  • Power stations and utilities

  • Plastic industry

  • Basic materials industry

  • Test stands

  • Conveyor technology and applications in general machinery construction

  • Retrofit for SIMOVERT A drives