Magnetic Fields

Linear 4-Quadrant Regulated Amplifiers


Magnetic Applications

How does the L behave?


1.  Power Dissipation

Here, the loss performance is usually at the top. Even if the full voltage of the power amplifier drops at the inductor, the full power from the amplifier must be absorbed as power loss.


2.  Frequency-dependent impedance

At low frequencies, the impedance of the inductor is very low, but the current is very high; At high frequencies, a high voltage is needed to let current flow through the L.

For example, To enable a complete sweep of a Helmholtz coil with 100A/m to over 150kHz, exceptional amplifiers such as the HERO®power PFL2250-28-UDC415-IDC375 are required. At low frequencies, 10kW dissipate power dissipation and at high frequencies more than 560Vrms are available.





1.  Line tests, e.g. Hall sensors—Hall switches—Linear Hall sensors as potentiometer replacement—Angle sensors —Motor controller

In this case, very high demands are placed on the magnetic field, especially in linear Hall sensors, e.g. Stabilities of better 1x10^-4. This magnetic field has to achieve this high stability in about 10msec, HERO®power has successfully solved such tasks.


2.  Particle Accelerator

The most important features of the quadrupole focusing magnets are:

  • highest stability
  • exact zero crossings
  • least distortions
  • Control: local / remote switchable

The decision was made for HERO®power in such important international tenders for the control of quadrupole magnets and for focusing the electron beam such as COZY (Cooler Synchrotron) in Jülich and Bessy II (Berliner Elektronenstrahl Synchrotron) in Berlin-Adlershof. We are still proud to have found ourselves on the list of <companies involved in the successful outcome of the COZY project>.

For both projects, we contributed more than 200 HERO®power linearly regulated four-quadrant amplifiers with exact zero crossings and minimal residual ripple.


3.  Beam control of the electron beam sources for the plasma-activated high rate evaporation of FEP

(Fraunhofer Institute for Electron Beam and Plasma Physics in Dresden / HZDR Dresden (Helmholtz Institute Dresden-Rossendorf))

Main features:

  • precisely controllable constant current sources up to 60Arms,
  • 100kHz, voltage swing 280Vrms
  • Control: local / remote switchable




Automotive + Component Tests + Magnetic Fields + Calibration of Hall effect sensors for automotive use.


Control variable VOUT / COUT switchable

±85A / ±150V

Power loss: 8,5kW


Magnetic field stability: better 1x10^-4

from 10msec after the start





Magnetic fields

Engine test stand

Control variable VOUT / COUT switchable

  Power: 10kVA continuous;  30kVA until temp. shutdown

Power dssipation: 5kW lasting;  15kW until temp. shutdown

  Performance ranges switchable

R1: ±300V / ±30A;   R2: ±200V / ±50A:   R3: ±30V / ±50A


Customized safety equipment





Generation of a magnetic field-free space for measuring the magnetic fields of the brain:

Simulation of the universe

Test of satellites and experiments
for space travel

PTB (Physikalisch Technische Bundesanstalt) / TUM Excellenzcluster Universe / Paul-Scherrer Institute Switzerland / Fierlinger Magnetics


Technical Data

Control variable VOUT / COUT switchable

±50V / ±70A

Potential conditions and input situation

Galvanic isolation input + output against monitor outputs

Input 1 = DC coupling;

Input 2 = AC coupling with switchable high-pass:

1Hz – 2Hz – 5Hz – 10Hz

Input 1 + 2 low pass: Off – 1kHz – 100Hz – 40Hz

Input specifications are added


Zero suppression of 10^-6




Magnetic fields

3 channels with ±180A / ±16V linearly controlled

Residual ripple 10^-5

Cooling: deionized water


Accelerator Bessy II / Berlin-Adlershof


Typ: PA 2003




Particle beam focusing in Cozy,
Bessy II and Desy


exact zero crossings

Ripple + Stability: 10^-6


Control with 24 Bit-BESSY II Interface





Metrology—High-frequency magnetic fields—antenna development—Component tests


HF amplifier series in a modular system

From ±40V … ±400V / ±1,5A … ±18A

Frequency Response:
DC...1.4MHz /…3db;  ca. 5MHz small Signal


Automotive antenna calibration,

Definition of traceable quantities (PTB)

Development of standards for the traceable calibration of high-frequency power





Component tests—bipolar symmetric


Epstein frame for testing transformer plates


Control variable VOUT / COUT switchable

±100Vrms / ±5Arms; DC … 30kHz …3db

3 adding setpoints: DC / DC+AC / AC

2 summing inputs: DC- bzw. AC-gekoppelt

adding zero offset ± 100% can be switched ON/OFF

Potential conditions: Floating construction—earthing possible


PA612B   optimized for Epstein frames



Magnetic Materials:
Development / Quality Control

Resolution 10^-6

• VOUT regulation

• Range 1:  ±280V / ±2,8A (200Vrms / 2Arms)

• Range 2:  ±70V / ±5,6A (50Vrms / 4Arms)

Reinforcements fixed:  1 – 5 – 10 – 20 – 40;

variable  0...100%; 10-turn potentiometer

with lockable scale drive

• Fine adjustment: ±10%; 10-turn potentiometer

with lockable scale drive

Dynamics: 18V/µs; see also < Traces >

2 summing inputs: DC or AC coupled


Adapted to the measuring task




Amplifier system for

Magnetic coils / Helmholz coils / Deflection coils


Limit values for the test arrangement

Cmax  40ASS

Vmax  1600VSS

DC - 150kHz …3dB

DC - small signal: 400kHz


2x PFL2250-28-UDC415-IDC375 interconnected


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