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Engineering guide · Technical specification

Switched or thyristor rectifier? How to specify an industrial DC system

An industrial rectifier should not be chosen only by nameplate voltage and current. The right decision considers load behavior, the battery bank, autonomy, recovery time, redundancy architecture, AC supply, environment, protections, supervision, and maintenance strategy.

Compare technologies

Technical content for specifiers, designers, maintenance teams, EPC contractors, and buyers of direct-current power systems.

The system as a whole

From the AC grid to the critical load

Switched and thyristor technologies can both feed critical loads and keep battery banks in suitable operating condition. The difference lies in how each architecture responds to the full set of project requirements.

01

AC grid

Primary utility supply

220 to 480 V AC
02

Rectifier

CIB.S · CIB.SP · CIB.T — converts AC into stable DC

24 / 48 / 110 / 125 / 220 VDC
03

DC bus

Stabilized direct-current distribution

Also feeds critical loads directly in DC
04

Battery bank

Kept on float charge, takes over if the grid fails

Carga flutuante — indicação ilustrativa
05

Inverter

Converts DC back into AC, when the project has AC loads to feed

06

Critical loads

Lighting, control, and telecom without noticing the transition

Alternating current (AC)Direct current (DC)Follow the numbered sequence 01 → 06
Starting point

The short answer: no single technology is universally better

The most suitable rectifier is the one whose architecture meets the full requirement with coherent reliability, maintainability, and total cost.

Switched solutions tend to stand out when power density, efficiency, low THDi, modularity, expansion, and fast module replacement are priorities.

Thyristor solutions tend to be considered when the project calls for high currents, traditional industrial architecture, extensive customization, an input transformer, and specific construction solutions.

These trends do not replace the analysis. High-power switched systems and compact thyristor systems both exist. Power factor, harmonics, ripple, redundancy, and protection can also be improved with different topologies and options.

The power stage is only one part of reliability. Redundancy, derating, component quality, ventilation, protection, supervision, documentation, testing, and support weigh as much as the conversion technology itself.

Before comparing

What is the function of the rectifier?

In a stationary DC system, the rectifier converts the AC supply into regulated DC voltage. In normal operation, it sustains the permanent loads and keeps the battery bank in an appropriate charge regime. In the absence of the grid or the rectifier, the battery takes over the bus for the autonomy time set out in the project.

01AC supply
02Rectifier/charger
03DC bus and distribution
04Battery bank
05Protection and sectioning
06Permanent and transient loads
07Supervision, alarms, and communication
08Cables, connections, grounding, and environment
Terminology

Industrial rectifier and battery charger: what is the difference?

The terms are often used as synonyms, but they describe different perspectives of the same equipment.

Rectifier

Describes the conversion function: turning the alternating-current supply into a controlled direct-current output.

Battery charger

Describes the electrochemical and operational function: applying to the battery the voltage and current regimes needed to keep it charged and to recover it after a discharge.

Industrial rectifier/charger

Combines both functions and typically also sustains the permanent loads on the DC bus, supervises the bank, and protects the system.

A charger intended only to replenish a battery may not have been sized to continuously feed all the critical loads on the bus at the same time. Likewise, a regulated DC source may feed a load without having the regimes, limits, sensors, and protections needed to properly manage a stationary bank.

FunctionDC sourceSimple chargerIndustrial rectifier/charger
Convert AC to DCYesYesYes
Sustain permanent loadPer projectMay not be the main functionYes, when specified
Controlled floatNot necessarilyYesYes
Recharge after dischargeNot necessarilyYesYes, simultaneously with loads per sizing
Temperature compensationOptionalPer modelMust be defined per battery and project
Supervision and alarmsLimitedPer modelIntegrated into the industrial system
DC distribution and protectionsUsually externalUsually limitedCan be part of the supply
SCADA integrationNot typicalCan be limitedA relevant part of the specification

For critical systems, the right question is not just "which charger to use?" but "which architecture will keep the bus and the battery within limits in every operating state?"

States the project must verify

  1. 1.Normal AC grid, battery floating, loads fed
  2. 2.Battery recharge with permanent loads on
  3. 3.Loss of the AC grid, battery feeding the loads
  4. 4.Grid return and controlled bank recovery
  5. 5.Loss of a module or rectifier
  6. 6.Maintenance of a unit
  7. 7.Communication or controller failure
  8. 8.Load step or peak
Comparison

Switched and thyristor, side by side

The comparison describes architecture trends, not a good-versus-bad contest between technologies.

Conversion principle

Switched
High-frequency switching by semiconductors, usually in modules
Thyristor-based
Controlled rectification synchronized to the grid, in single-phase or three-phase topologies
In the specification
Accepted technology or required performance

Power density

Switched
Usually high
Thyristor-based
Usually lower for the same power
In the specification
Available space, access, and maximum dimensions

Modularity

Switched
Naturally favorable to modules in parallel
Thyristor-based
Can operate in parallel, but is usually configured in larger sets
In the specification
N, N+1, 2 × 100%, or another philosophy

Maintenance

Switched
Fast module swap can reduce MTTR
Thyristor-based
Maintenance of assemblies and internal components by a technical team
In the specification
Spare-parts strategy and allowable repair time

Expansion

Switched
Adding modules can be planned in the project
Thyristor-based
Expansion usually requires assessing the architecture, buses, and cooling
In the specification
Initial capacity and physical/electrical reserve

Efficiency

Switched
Tends to be high
Thyristor-based
Depends on topology, power, and operating point
In the specification
Minimum efficiency and measurement conditions

Power factor and THDi

Switched
Usually favorable in architectures with active correction
Thyristor-based
Depend on the pulse number, load, transformer, and filters
In the specification
Limits at the connection point and load range

Output ripple

Switched
Usually low due to switching frequency and filtering
Thyristor-based
Controlled by topology and output filter
In the specification
RMS/peak-to-peak limit and condition with/without battery

Ventilation

Switched
Modules frequently use forced ventilation
Thyristor-based
Can allow natural ventilation at certain power levels
In the specification
Temperature, airflow, redundancy, and fan replacement

Input transformer

Switched
Can be external, integrated, or omitted depending on architecture
Thyristor-based
Commonly integrated in industrial solutions
In the specification
Galvanic isolation, shielding, ratio, and thermal class

Current ranges

Switched
Wide and scalable by modules
Thyristor-based
Particularly suited to high currents and custom projects
In the specification
Continuous current, recharge, overload, and expansion

Construction customization

Switched
High at the system and cabinet level
Thyristor-based
Traditionally broad in topology, panel, and accessories
In the specification
IP rating, paint, cable entry, segregation, and dimensions

Typical best fit

Switched
Modularity, efficiency, compactness, and expansion
Thyristor-based
High current, custom industrial architecture, and traditional requirements
In the specification
The final decision must be validated by the project

The comparison describes architecture trends, not absolute limits. The guaranteed values must be those of the proposal, datasheet, and test procedure of the equipment supplied.

Explore the switched CIB.SExplore the portable CIB.SPExplore the thyristor CIB.T
Typical application

125 VDC rectifier for substations: what must actually be defined

The 125 VDC bus is widely used in substation auxiliary services for protection, control, signaling, automation, telecommunications, and breaker tripping. However, "125 VDC" is a nominal system voltage — not a fixed voltage across every operating state.

The project must check the full window: bank float voltage; maximum voltage during boost charge or equalization, when allowed; voltage during discharge; the bank’s final voltage at the end of autonomy; drops across cables, protections, and diodes; and the minimum and maximum voltage allowed by each load class.

Conceptual example of the voltage window

Maximum load voltageEqualization / boost charge|Float|DischargeMinimum load voltage

Overlay two ranges: the bank’s expected operating range and the range allowed by the loads. If the ranges do not overlap, the project may require adjusting the number of cells, revising the charge regime, a diode-drop unit, load segregation, or DC/DC conversion — there is no automatic solution.

Eight blocks of a 125 VDC specification

LoadsPermanent, temporary, momentary current, cycle, and simultaneity
BankChemistry, number of cells, Ah, autonomy, voltage per cell, and temperature
RectifierLoad + recharge current, current limit, regulation, ripple, and redundancy
AC supplyVoltage, phases, tolerance, frequency, alternative source, and short-circuit level
BusIsolated or referenced, sectioning, allowable drop, and short-circuit current
ProtectionsInput, rectifier, battery, loads, surge arresters, earth leakage, and selectivity
SupervisionMeasurements, alarms, events, dry contacts, and protocols
ConstructionIP rating, temperature, ventilation, cable entry, access, paint, and dimensions

Typical loads that require attention

  • Protection relays and control units
  • Breaker opening and closing circuits
  • Spring-charging motors
  • Automation and telecommunications systems
  • Signaling and annunciators
  • Inverters and converters fed by the bus
  • Lighting or emergency services, when part of the same system

Coils and motors can produce short-duration demands far above the permanent load. The calculation memory must place these events within the discharge cycle and check the available voltage at the most distant point.

Related NPT solution

The CIB.S, CIB.SP, and CIB.T families have published configurations for 125 VDC. Choosing among them mainly depends on current, format, modularity, input quality, environment, and maintenance strategy.

Selection criteria

Which technology tends to fit your project?

Initially consider a switched architecture when...

  • Available space is limited.
  • Energy efficiency and power factor carry relevant weight.
  • The project values low THDi and low ripple.
  • There is interest in modular N+1 redundancy.
  • Maintenance should happen through fast module replacement.
  • Future expansion by adding capacity is anticipated.
  • The application calls for a 19" rack format or a portable solution.

Initially consider a thyristor architecture when...

  • The system requires high continuous currents.
  • The specification calls for 6- or 12-pulse topologies.
  • The project requires a high degree of electrical and construction customization.
  • Input transformer, isolation, and panel layout are central parts of the solution.
  • The maintenance strategy favors accessible industrial components and field technical intervention.
  • There are traditional utility, generation, industrial plant, or critical infrastructure requirements that already define this architecture.

Do not decide by technology alone when...

  • The load has relevant current peaks or switching events.
  • The maximum equalization voltage approaches the loads’ limit.
  • The system will have two rectifiers or two banks.
  • The AC supply is unstable, limited, or shared with disturbing loads.
  • There are special requirements for short-circuit, selectivity, EMC, seismic conditions, corrosive atmosphere, or protection rating.
  • The customer requires a specific protocol, such as IEC 61850 or DNP3.

Engineering conclusion: the system envelope is defined first. Then the technology capable of meeting it with the most coherent architecture is chosen.

Quick decision map

Answer five questions for an initial fit

The result only indicates an initial fit among CIB.S, CIB.SP, and CIB.T — never a completed sizing.

Question 1 of 5

What is the dominant priority?
Sizing

How to size the rectifier and battery bank: 10 connected decisions

The rectifier and the battery must be sized as parts of the same system, but through different checks. The bank sustains the load cycle during a source loss; the rectifier feeds the loads under normal conditions and restores the energy drawn from the battery within the required time.

01

Define the application and criticality

Start with what the DC system keeps running. Protection relays, breaker commands, automation, telecommunications, signaling, lighting, instrumentation, and inverters have different load profiles.

Record: segment and installation; function of the loads fed; consequence of losing the DC bus; maximum allowable downtime; the plant’s contingency philosophy; and the customer’s standards and particular specifications.

The more critical the load, the more important it is to eliminate single points of failure and prove selectivity, autonomy, and maintainability.

02

Determine the bus voltage and the allowable window

The nominal voltage — 24, 48, 110, 125, or 220 VDC, for example — does not define the system by itself. It is necessary to know the minimum voltage accepted by the loads at the end of autonomy; the maximum voltage accepted during float, boost charge, or equalization; the number of cells in the bank; the voltage drop across cables, breakers, fuses, and diodes; the need for a diode-drop unit; and the tolerance of connected sensors, relays, coils, and electronics.

The lower worst case must consider the bank’s final voltage under discharge and the drops to the most distant load. The upper worst case must consider the bank’s highest charge level and the loads’ tolerance.

Common mistake: specifying "125 VDC" without stating the actual range allowed by the loads.

03

Build the load cycle

Splitting loads into categories avoids sizing by simply adding up nameplate values: permanent (run through the whole cycle), temporary (run for defined periods), momentary (solenoids, coils, motors, or short-duration commands), and sequential (come on at different moments of the emergency scenario).

For each load, record power or current, duration, start time, simultaneity, minimum voltage, and the nature of its behavior. Sizing must reproduce the worst plausible operating cycle, not just the average current.

04

Size the battery bank separately

The bank is defined from the load cycle, autonomy, final voltage per cell, temperature, battery technology, aging, and design margins. For stationary lead-acid batteries, IEEE 485 describes methods for defining the load and sizing the bank; other chemistries require their own criteria and standards.

Minimum data: battery technology and manufacturer; number of cells; nominal capacity in Ah; float voltage per cell; boost charge/equalization voltage when applicable; final discharge voltage; required autonomy; minimum and maximum temperature; adopted aging factors and margin; and the manufacturer’s discharge curves.

The rectifier and the battery are interdependent, but should not be "sized by the same calculation." IEEE 485 covers the lead-acid bank; the DC system and the charger require their own analysis.

05

Calculate the required rectifier current

Under normal conditions, the rectifier must feed the loads that remain on and make current available to restore the bank within the set deadline.

A preliminary check can be represented as: I_rectifier ≥ I_loads_during_recharge + I_battery_replenishment. As an initial approximation: I_battery_replenishment ≈ (Ah to restore × recharge factor) / available time.

The recharge factor and the current limit must be set based on the chemistry, the battery manufacturer, the depth of discharge, the temperature, and the charger’s characteristics. Charge acceptance is not constant throughout the process, so the expression does not replace the manufacturer’s curve or the calculation memory.

The following must also be checked: the loads’ permanent current; peaks and load steps; recharge time after the specified autonomy; the battery’s allowable current limit; sharing between rectifiers; operation with a module or unit unavailable; technical reserve and future growth; and derating for temperature and altitude.

Common mistake: using only the bank’s Ah capacity to choose the rectifier current while ignoring the permanent load.

06

Define the availability architecture

The most common architectures include: N (installed capacity sufficient for the design condition, with no reserve); modular N+1 (one module beyond the quantity required); 2 × 100% (two rectifiers, each capable of meeting the defined condition); sectioned or A/B buses (segregation to limit common-mode failures); and two independent banks, when the availability philosophy requires full separation.

N+1 does not, by itself, mean full redundancy. Even with a spare module, shared elements may still exist: AC supply, main breaker, controller, backplane or subrack, DC bus, battery protection, ventilation, communication, and output distribution.

The specification must state which failures can occur without losing function and whether maintenance can be performed with the system energized. It must also define the behavior after a controller failure and the autonomy available during maintenance.

07

Specify the AC supply and power quality

State: nominal voltage and number of phases; permanent and transient voltage range; frequency and tolerance; grounding scheme; available short-circuit level; normal and alternative source; need for an isolation transformer; overvoltage category and surge arresters; minimum power factor; maximum THDi and measurement condition; inrush/starting current; and generator compatibility, when applicable.

The pulse number of a thyristor solution, the presence of a transformer, filters, and the input architecture all influence power factor and harmonic distortion. In switched solutions, these parameters depend on the power-factor-correction stage and the operating point. Requiring only "high power factor" without stating the load and test condition produces an incomplete comparison.

08

Define performance, battery, and protection

Output performance: static regulation; response to load steps and recovery time; RMS ripple and, if needed, peak-to-peak; measurement condition with and without battery; current and voltage accuracy; long-term stability; current sharing; current limiting; and cable-drop compensation, if applicable.

Battery management: float; boost charge/equalization when authorized by the manufacturer; current limit; temperature compensation; reverse-polarity protection; open battery circuit detection; LVD, when the philosophy allows it; and testing or supervision of the bank, when required.

System protections: AC/DC overvoltage and undervoltage; phase loss and sequence; short-circuit and overcurrent; overtemperature; ventilation failure; bus earth leakage/insulation; surge arresters at the input and output per analysis; individual protection for the rectifier, battery, and loads; and coordination and selectivity between devices.

The battery can contribute high short-circuit current. Protection and selectivity must account for the contributions of the bank and the rectifiers, in addition to cable and bus capacity.

09

Close out environment, construction, and maintenance

Specify: indoor or outdoor installation; temperature and humidity, including condensation; altitude and derating; saline, corrosive, dusty, or contaminated atmosphere; IP protection rating with doors open and closed; seismic requirements, when applicable; natural or forced ventilation; fan redundancy and monitoring; top or bottom cable entry; segregation, accessibility, and maintenance space; color, paint, sheet metal, base, and lifting; acoustic noise; conformal coating for boards; service life and spare-parts availability; targeted MTTR; and competency available on site.

Designing only for the room’s average temperature may be insufficient. The worst case, the panel’s internal temperature rise, clogged filters, degraded ventilation, and operation after losing a redundant element must all be assessed.

10

Define supervision, documentation, and testing

Signals and communication: voltage and current measurement of the rectifier, battery, and load; breaker and fuse status; urgent and non-urgent alarms; AC failure, rectifier failure, and bank failure; overvoltage, undervoltage, earth leakage, and temperature; timestamped event history; digital/analog inputs and outputs; dry contacts; Modbus RTU/TCP, SNMP, IEC 61850, DNP3, or the required protocol; and point mapping and integration documentation.

Minimum documentation: completed datasheet; single-line diagram; functional and interconnection diagram; general layout and dimensions; bill of materials; cable and terminal list; control and alarm philosophy; communication point list; sizing calculation memory; performance curves or limits; installation, operation, and maintenance manual; spare-parts list; and inspection and test plan and report.

FAT — tests to consider: visual and dimensional inspection; component and labeling check; insulation resistance and dielectric strength per the project and applicable standard; functional check of protections and interlocks; voltage regulation and current limiting; ripple under the specified condition; response to input and load variations, when foreseen; current sharing and module/unit loss; battery charge modes; local and remote alarms and event logging; communication and point map; and the unit’s autonomy test, when part of the scope.

The acceptance criteria, instrument, test load, thermal condition, and tolerance must be defined before the FAT.

Availability

N+1 redundancy in DC systems: excess capacity and single points of failure

N+1 does not, by itself, mean full redundancy. Even with a spare module, shared elements may still exist: AC supply, main breaker, controller, backplane or subrack, DC bus, battery protection, ventilation, communication, and output distribution.

Consistency test for an N+1 architecture

The project should only call the solution N+1 after answering:

  1. 1.How many modules are needed to feed the loads and the recharge in the project scenario?
  2. 2.After losing a module, does the remaining capacity still meet the full requirement, or only the permanent load?
  3. 3.Is there derating for temperature, altitude, or input voltage?
  4. 4.Is the controller redundant, or does its failure preserve module regulation?
  5. 5.Does each module have independent protection and disconnection?
  6. 6.Can a module be safely replaced without taking the bus out of service?
  7. 7.Is there shared ventilation, AC supply, or backplane capable of interrupting all modules?
  8. 8.Are the bank and the distribution still single points of failure?

Modular N+1 versus 2 × 100%

AspectModular N+1Two 100% rectifiers
Capacity reserveOne module beyond NA complete unit beyond what is needed, per philosophy
MaintenanceCan favor fast module replacementCan allow isolating an entire rectifier
Common failuresController, rack, input, and bus must be checkedBus, bank, distribution, and possibly AC can still be shared
ExpansionUsually simple if there is physical and electrical reserveUsually through a new unit or a planned expansion
SegregationDepends on the system architectureCan be greater if inputs, protections, and panels are independent

N+1 improves availability when the failure considered is at the module level. Two independent units can increase segregation, but they also do not automatically eliminate every common-mode failure.

Charge strategy

Ripple, float, equalization, and temperature compensation

These four topics are related, but not interchangeable. Ripple is an electrical output characteristic; float, equalization, and temperature compensation are parts of the battery charge strategy.

Ripple: the alternating component over the DC voltage

Ripple is the residual ripple present on the DC output. Its assessment must state the RMS value and, when relevant, peak-to-peak; the frequency band and measurement method; the applied load; the condition with or without battery; the modules’ operating state; and the point where the measurement was taken.

Excessive ripple can affect sensitive electronics, measurements, communication, and the battery. The battery can change the ripple observed on the bus, but it does not replace a clear rectifier performance requirement.

Float: keeping the battery ready

In float, the charger maintains a defined continuous voltage to offset self-discharge and preserve the state of charge, while feeding the system’s loads. The correct value depends on chemistry, manufacturer, number of cells, and temperature.

Excessive voltage can increase float current, corrosion, gassing, or aging. Insufficient voltage can keep the bank undercharged and reduce its available capacity.

Equalization or boost charge: use only when applicable

Equalization, boost, or accelerated charge should not be treated as a single universal regime. The purpose, voltage, duration, limit current, and end criterion depend on the technology and the battery manufacturer’s instructions. Some vented banks may allow periodic or corrective equalization; VRLA batteries usually require strict limits; nickel-cadmium batteries follow their own parameters.

The logic must prevent the higher-voltage regime from exposing the loads to values above what is allowed. When necessary, evaluate a diode-drop unit, segregation, or another engineering solution.

Temperature compensation: adjusting voltage to the battery’s actual temperature

The optimal voltage per cell varies with temperature. Temperature compensation adjusts the setpoint according to the temperature measured on the bank, following the manufacturer’s curve. Minimum requirements: sensor in a representative position on the bank; coefficient defined by the battery manufacturer; stated reference temperature; upper and lower compensation limits; alarm for sensor failure, disconnection, or implausible reading; a safe fallback strategy; and a ban on using a generic coefficient across different chemistries.

Communication

IEC 61850, Modbus, DNP3, and supervision of DC systems

The protocol is only the transport and data-organization layer. A useful integration also depends on the signal list, semantics, resolution, timestamps, quality, allowed commands, cybersecurity, network architecture, and interoperability testing.

CriterionModbus RTU/TCPDNP3IEC 61850
Basic modelRegisters and bits mapped by the manufacturerObjects and classes oriented to automation/telecontrolSemantic data model, services, and configuration language
Common mediumSerial RS-485/RS-232 or Ethernet TCP/IPSerial or IP networks, depending on implementationEthernet in modern applications
Typical integrationPLC, HMI, gateway, and industrial SCADASCADA and utility telecontrolSubstation automation and interoperable electrical systems
EngineeringRequires a register mapRequires profile, objects, classes, and pointsRequires model, logical nodes, datasets, services, and applicable SCL files
EventsDepend on the map and the implementationDesigned for efficient event and state communicationServices and models depend on the profile and implementation
ComplexityLowerIntermediateHigher, with a scope well beyond "a single protocol"

The IEC 61850 series combines standardized data models, communication services, and SCL configuration language for lifecycle interoperability. For a rectifier, simply stating "has IEC 61850" is not enough — it is necessary to define native or gateway implementation, edition and applicable parts, the logical nodes and data objects used, reports and datasets, ICD/CID/SCD files, time synchronization, and integration testing with the SAS/SCADA.

Modbus requires an unambiguous map (offset, register type, byte order, scale, and fail value). DNP3 must be defined as an implementation profile — requesting a "DNP3 port" is not enough; objects, variations, classes, events, deadbands, timestamps, and tests with the customer’s master must be agreed upon.

A good system does not just report "general failure." It delivers enough information to locate the source, assess the impact, and guide the intervention — local supervision remains indispensable even with remote integration.

Synthesis

A specification is not a list of numbers: it is an operating philosophy

Two rectifiers with the same voltage and current rating can produce very different results once connected to the real system. The difference shows up in the response to load steps, behavior during failures, selectivity, battery management, repair time, and integration with operations.

  1. 1.What cannot stop?
  2. 2.For how long must the battery sustain the system?
  3. 3.What is the voltage window accepted by the loads?
  4. 4.In how much time must the bank be recovered?
  5. 5.What failure can occur without loss of function?
  6. 6.How will maintenance be carried out?
  7. 7.How will operations be informed about failures?
  8. 8.How will performance be proven at the FAT?
Risks

Mistakes that most weaken a specification

Adding up only the nameplate currents

Ignores duration, simultaneity, steps, and load sequencing.

Choosing current as a fixed percentage of Ah

Can ignore the permanent load, recharge deadline, chemistry, and the battery manufacturer’s limit.

Stating only the nominal voltage

Does not validate the minimum voltage at the end of discharge or the maximum voltage while the bank is charging.

Calling any modular architecture redundant

Can hide a shared controller, input, bus, ventilation, or protection.

Comparing ripple without stating the measurement condition

Results with battery connected, without battery, at partial load, or with different measurement bands are not directly comparable.

Requiring a protocol without defining points and services

The name "IEC 61850" or "Modbus" does not replace a signal list, architecture, files, and integration testing.

Not specifying environment and maintenance

Temperature, dust, salinity, altitude, access, and spare-parts availability can determine the actual reliability.

Leaving the FAT for the end

Without prior criteria, the test may only prove the equipment turns on — not that it meets the application.

CIB line

How the CIB family positions itself

Modular switched

CIB.S

For systems that prioritize modular architecture, power density, efficiency, and the option of redundancy configured per project.

  • 24 / 48 / 125 VDC
  • Up to 12 RM rectifier units
  • Published power factor ≥ 0.99
  • Published efficiency ≥ 92%
  • Published THDi ≤ 5%
  • Published regulation ≤ 1%
  • Floor-standing industrial enclosure
See specifications for CIB.S
Portable switched or 19" rack

CIB.SP

For applications where space, mobility, or rack integration are part of the requirement.

  • 24 / 48 / 125 VDC
  • Up to 12 kW
  • Portable unit or 19" rack drawer
  • Interchangeable modules
  • Published power factor ≥ 0.99
  • Published efficiency ≥ 92%
  • Published THDi ≤ 5%
See specifications for CIB.SP
Thyristor-based

CIB.T

For industrial and critical-infrastructure systems that demand high current and broad electrical and construction configuration.

  • 24 / 48 / 110 / 125 / 220 VDC
  • Up to 2,000 A
  • Single-phase 2-pulse and three-phase 6- or 12-pulse topologies
  • Published regulation ≤ 1%
  • Published ripple ≤ 1%
  • Industrial panel per specification
See specifications for CIB.T

The ranges shown represent the published possibilities of the families. The configuration and the guaranteed values of each supply are defined in the technical proposal and the project documents.

Checklist

Information to start the specification

Gather this information before talking to our Engineering team — if something is not yet defined, send whatever already exists.

Application

  • Segment and installation site
  • Function of the critical loads
  • Standards/customer-specific requirements

DC bus

  • Rated voltage
  • Minimum and maximum voltage allowed by the loads
  • Permanent current
  • Temporary and momentary loads
  • Future growth

Battery

  • Technology and manufacturer
  • Number of cells and Ah capacity
  • Float, equalization/boost charge, and final voltage
  • Autonomy
  • Recharge time
  • Reference temperature

Architecture

  • N, N+1, 2 × 100%, or A/B buses
  • Elements that cannot be shared
  • Live or de-energized maintenance
  • Spare-parts strategy

Supply and environment

  • AC voltage, phases, and frequency
  • Variation range and alternative source
  • Temperature, humidity, and altitude
  • IP rating and atmosphere
  • Cable entry and available space

Integration and testing

  • Dry contacts and signals
  • Protocol and point list
  • Required documentation
  • FAT plan and acceptance criteria

If not all the data is available, send what has already been defined. The NPT team helps identify the missing information before the final configuration.

Questions frequentes

Questions about rectifier specification

Design references

The standards below are cited as engineering references applicable to the topic, not as certification of the CIB family. No regulatory compliance should be assumed without specific documented proof.

The rectifier must be born from the requirement.

Send your DC system’s data. NPT Engineering evaluates voltage, current, battery bank, architecture, protection, supervision, and construction configuration to indicate the technically suitable solution.

Talk to our Engineering team