Rectifier for stationary battery systems

  • Safe
  • reliable
  • powerful
  • economical
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Robust and reliable, tried and tested

Battery-supported DC power supply systems have proven to be extraordinarily reliable and very economical back-up power supplies for many decades. The reliability of a battery-supported backup power supply depends on the quality of the battery used and the operational reliability of the rectifier device.

BENNING has developed the THYROTRONIC rectifier series to be particularly suitable for use with battery-supported DC power supplies. In addition to great reliability, it offers a comprehensive signalling and monitoring concept.

Reliable in harsh environmental conditions
  • Constructed from few but reliable components
  • Mechanically and electronically resistant, designed for harsh environmental conditions
  • Wiring concept
  • State-of-the-art DSP technology
  • Automatic temperature-controlled charging characteristic
  • Galvanic isolation
  • High quality output power
  • Fully controlled thyristor three-phase bridge, 6 pulse (standard), 12 pulse (optional)
Suitable for all battery technologies

THYROTRONIC rectifier devices work with an electronically controlled output characteristic (IU characteristic according to DIN 41773) and are suitable for use with lead and NiCd batteries as well as other modern battery technologies.

Course of the IU characteristics in accordance with DIN 41773
Functional variety
  • various signaling and monitoring modules
  • Suitable for all battery technologies
  • Programmable automatic boost charge
  • Equalising and initial charge
  • Parallel operation of several rectifiers with active or passive load sharing
  • Automatic and programmable battery circuit test
  • Automatic battery capacity test
  • Compensation of line resistance
  • Display of the remaining battery life

THYROTRONIC rectifier series – Constructed from few but reliable components

THYROTRONIC circuit diagrammes
THYROTRONIC circuit diagrammes
THYROTRONIC Rectifier with exterior and interior view
THYROTRONIC Rectifier with exterior and interior view

Signalling and monitoring modules

Signalling and monitoring modules

THYROTRONIC 10“ touch display with mimic diagram
THYROTRONIC 10” touch display
Modern touch display with intuitive guidance through a user interface optimized by BENNING
Extended THYROTRONIC basic display frontview
Extended THYROTRONIC basic display
Equipped with a display and control unit (LCD and pushbuttons) and a freely configurable status display
THYROTRONIC basic display frontview
THYROTRONIC Basic display
Display and control unit with LCD and push buttons

All available measurement channels can be provided with measurement and error thresholds. Freely definable limit values can be set to trigger the error or warning messages. The display and control unit built into the front door of the rectifier housing is used to enter the limit values and to confirm and visualise the messages. Optionally, the system can be equipped with a 10” touch display, which sets completely new standards in terms of ease of use and comprehensibility.

Supported monitoring types:

  • Network monitoring
  • Battery and DC voltage monitoring
  • Temperature monitoring
  • Over- and undervoltage monitoring


Battery-backed DC power supplies based on the THYROTRONIC rectifier series are perfectly suited for:

Energy suppliers and network operators
Operationally safe & reliable

Ideal for power plants and substations

  • Mechanically and electronically resistant, designed for harsh environmental conditions
  • Operationally safe
    • Galvanic isolation
Industrial plants
Modern industrial technology with a robotic Arm in an automated production cell
Reliable & economical

Robust for industrial applications

  • Designed for harsh environmental conditions
  • Operationally safe
    • Galvanic isolation
  • High quality output power
  • Powerful and economical
Raw material extraction
Yokkaichi industrial complex, night view of the factory
For harsh environmental conditions

Constructed from few but reliable components especially suitable for:

  • Oil, gas and petrochemical industry
  • Mining installations
Safety for critical processes

Robust rectifier system for critical infrastructure protection

  • Mechanically and electronically resistant,
  • Operationally safe
    • Galvanic isolation
  • High quality output power
  • Suitable for all battery technologies
Transport and traffic
Passenger plane fly up over take-off runway from airport
Robust & safe

Reliable when it counts, ideally suited for:

  • Railway systems
  • Airports
Table with coffee, biros and a BENNING THYROTRONIC brochure in hand

Rectifier for stationary battery systems

  • Safe
  • reliable
  • powerful
Rectifier / inverter system cabinet, populated with inverter modules TEBECHOP SE and MCU-300

Rectifier systems and DC converters with modular technology

  • scalable, robust and cost-effective
  • well-suited to deal with industrial requirements
One contact person for the entire project
BENNING – One contact person during the entire product lifecycle
  • You get the most economical solution and benefit in the long term from the direct link to BENNING as the manufacturer.
  • Quality made in Germany
IMS - Integrated Management System Logo
IMS - Integrated Management System
  • Quality Management
  • Environmental Management
  • Occupational Safety and Health Protection


Further details on our THYROTRONIC rectifier systems

  • 10" touch screen
  • Analogue display instruments
  • MODBUS, IEC 61850 and many more
  • Battery cabinets / distribution cabinets
  • Internal and external countercells
  • External battery connection boxes (opt. Ex-d / Ex-de types)
  • Decoupling diodes
  • Ground fault monitoring
  • Parallel operation with and without active load sharing
Why do THYROTRONIC rectifier systems use standby parallel operation?

The service life of lead-acid and nickel-cadmium batteries can be maximised if they are at rest in a charged state. This resting state of the batteries is achieved when the rectifier unit takes over the load supply and the battery is only stressed in the event of a mains failure or a large shock load. This operating mode is called Standby parallel operation.

In the event of a mains supply failure, the battery system takes over the supply of the connected loads without interruption. When the mains power returns, the battery is automatically recharged.

Which charging characteristics does the rectifier use?

If the battery is very heavily discharged, the rectifier first operates in the I-branch of the IU characteristic curve, where the charging current is the difference between the nominal current of the rectifier and the current load.

When the set output voltage is reached, the transition to constant voltage charging (U-branch) takes place.

Accelerated recharging is achieved by switching the characteristic curve from float charging (e.g. 2.23 V / Z for lead batteries) to charging (e.g. 2.4 V / Z for lead batteries).

After the battery is fully chargedit will still draw the float charge current, which is between 0.3 mA and 1 mA per 1 Ah of battery capacity.

How does a THYROTRONIC rectifier behave with regard to output voltage, mains voltage and mains frequency fluctuations?

The output voltage is kept constant with a deviation of ± 0.5 % within a load range of 0 % to 100 % of the unit current.

Mains voltage fluctuations of ± 10 % and mains frequency fluctuations of ± 5 % are compensated.

Battery circuit test

The battery circuit of the power supply system can be tested in a set cycle. This can be activated in the menu. For this purpose, the rectifier output voltage is lowered to an adjustable value, e.g. 1.9 V / cell for a short period of time. This minimally discharges the battery for a short time.

At the same time, the battery voltage is checked. If it remains above the set value, the battery circuit is OK. If it falls below the limit value, the message "Battery circuit fault" is displayed and the LED and common alarm relays are activated.

Battery capacity test

In the battery capacity test, as in the battery circuit test, the rectifier output voltage is lowered and the battery is discharged with a constant current. During this test, the voltage and current time curves are recorded and compared against the manufacturer's data sheet values. The results of this test include the remaining capacity of the battery system and the resulting remaining running indication at current load.
If the set marginal parameters are violated during this test, the corresponding LED and the collective fault signal relay indicate the faulty test procedure. After the test has been completed, the rectifier unit automatically switches back to charging or float charging.

Alternatively, the current battery condition can be validated by a partial discharge with the load current that is currently applied.

Compensation of the line resistance

The voltage drop on the line between the rectifier and the battery can be compensated by entering the line length and the line cross-section. This ensures that the battery system is supplied with the correct voltage even if the battery connection cables are long.

Programmable automatic charger

If the battery voltage drops due to a mains failure or another circumstance to an extent that the rectifier unit operates in current limitation for longer than 30 seconds after charging has started, the system automatically switches to the boost charging characteristic. After the charging voltage (voltage limit) is reached and the current drops below 90%, a time stage is activated. After the set time (0 to 48 hours) has elapsed, the system automatically switches back to float charge.

The automatic charging function is adjustable and can be activated or deactivated as required.
A manual boost charge, a manual switchover and a float charge can all be activated at any time from the unit's display.

The switchover to charging can be blocked by an external contact or a fixed jumper on the controller (e.g. external hydrogen sensor in the battery room).

Alternatively, a manual selector switch for charging / float charging is offered as an option.

Equalising charge / Initial charge

Equalising charging can be switched on from the display. To do so, the voltage value and the current limitation can be set on the display.
Please note that before activating this operating mode, check your loads for the set voltage value and disconnect them if necessary to avoid damaging them with the high voltage.

When equalising charge is switched on, a timer is started which automatically switches back to float charge after the programmed time (0 - 48 hrs) has elapsed. The switchover to equalising charge can be blocked by an external contact or a fixed jumper on the controller.

Current sharing with parallel connection

When several rectifiers are connected in parallel in conjunction with the parallel run option, the load is distributed symmetrically to all rectifiers that are connected and switched on.
Without the parallel run option, load sharing is largely determined by line impedances.
The use of decoupling diodes with rectifiers connected in parallel is recommended.

BENNING is your contact for reliable rectifiers and battery-supported DC power supply systems of all kinds. Contact us now.


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USA BENNING Power Electronics, Inc.
Technical Support Hotline

+1 800 910 3601

USA BENNING Power Electronics, Inc.
Services Support

+1 214 553 1444


1220 Presidential Drive
Richardson, Texas 75081

USA BENNING Power Electronics, Inc.

+1 214 553 1444


1220 Presidential Drive
Richardson, Texas 75081

USA BENNING Power Electronics, Inc.
Customer Helpdesk

+1 214 553 1444


1220 Presidential Drive
Richardson, Texas 75081