Braking resistors

The speed of modern three-phase synchronous squirrel-cage motors and three-phase synchronous motors is usually controlled by a variable frequency drive (VFD). The AC frequency of the VFD output voltage determines the motor speed and can be adjusted independently of the mains voltage.

In operating conditions in which the electrical drive serves as a generator (e.g. when driving downhill, lowering or braking), the generated energy of the motor results in a voltage increase in the DC bus of the VFD. To prevent damage to components, the DC bus voltage must remain below a specified critical value.
In many cases, feeding energy back into the grid is not economical. Instead, the extra energy is converted into heat using a chopper and a dynamic braking resistor.

A further variant is the use of a three-phase braking resistor in direct combination with the motor. Therefore, the resistor is connected to a contactor in the three-phase circuit of the motor. The motor windings are therefore short-circuited in a controlled manner using resistors. The objective of this extremely robust switch is to ensure braking action independent of the chopper unit of the DC intermediate circuit. This switch is often used for the emergency stop function of a machine.

Thanks to their extensive expertise in this field, gained over a period of many years, FRIZLEN is happy to advise you on the correct configuration of your dynamic braking resistor. Here, we can offer you the optimum technical and economical solution with our diverse product portfolio.

Potential fields of application

Drive Technology

The range of uses in connection with drive technology is almost never-ending; although the respective requirements are similar: Excellent availability, low maintenance requirements and reliable monitoring equipment: FRIZLEN offers a suitable braking resistor for virtually all requirements.

Example series:
T100 | FZ.C
Industry:
drive technology

Machine tools

Whether they are integrated into the device or onto the switch cabinet in a protected version: FRIZLEN currently offers a broad product range of braking resistors for momentary peak loads in limited installation spaces. Our customers from the machine tools industry often use FRIZLEN flat resistorsfor this very purpose; we can supply these for a maximum voltage range of 4200 VDC.

Example series:
T300 | KWAD
Industry:
machine tools

High-bay storage

The linkage of automated high-bay storage with production plants is a measure which enables significant productivity gains to be made today. A prerequisite for production at full capacity is a continual and secure material flow in the storage system, which is achieved by means of a high-quality storage control system. Smooth start-up, braking and high speeds must be brought into harmony. FRIZLEN power resistors provide their own contribution in this area.

Example series:
T600 | FGFL
Industry:
high-bay storage

Lift construction

In modern lift systems with an electrified drive, the energy is partially fed back into the mains during braking. However, it is still the case that in many systems, an elaborate feedback of braking energy is not cost-effective or only partly cost-effective. In such cases,FRIZLEN braking resistors are a sensible alternative or addition.