A BK Series industrial control transformer is designed to provide stable and reliable control power for industrial machinery, machine tools, CNC machines, electrical control panels, automation equipment and auxiliary electrical circuits. It steps the available primary voltage down or up to the required control voltage for components such as contactors, relays, solenoid valves, PLC circuits, sensors, indicator lights and motor control circuits.

Compared with a general-purpose power transformer, a control transformer is designed specifically for control circuits where stable voltage and reliable performance during switching and inrush conditions are important. VoltNex Power supplies BK Series control transformers for industrial automation, machine-building and electrical equipment applications.

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A BK control transformer is optimized for industrial control circuits rather than general power distribution. It is commonly used to provide a dedicated control voltage for contactors, relays, solenoids, PLCs, indicators and other control components.

Important selection factors include VA capacity, primary voltage, secondary voltage, inrush current, voltage regulation, frequency, insulation class and installation space. A standard power transformer may be suitable for some applications, but a properly selected control transformer is generally better suited to machinery control circuits with frequent switching and inductive loads.

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The BK Series page is positioned for 500VA to 100kVA industrial control transformer applications, with custom capacities available for OEM and project requirements. Typical application ranges include smaller control circuits, industrial machinery, control cabinets, automation equipment and higher-power industrial systems.

When selecting a rating, the transformer should be sized according to both the continuous VA load and the maximum inrush VA of connected devices such as contactors, solenoids, motors and other electromagnetic loads.

For a custom BK transformer, provide the required VA/kVA rating, primary voltage, secondary voltage, frequency and load profile so the engineering team can recommend the appropriate configuration.

Start by calculating the total steady-state VA load of all control components that may operate simultaneously. Then evaluate the maximum inrush VA produced when contactors, relays, solenoid valves or other inductive loads are energized.

A practical selection should consider:

• Continuous control load
• Maximum simultaneous load
• Contactors and relay inrush
• Solenoid inrush
• PLC and electronic control loads
• Motor starter circuits
• Future load expansion

The selected control transformer should have sufficient capacity to prevent excessive voltage drop during starting or switching conditions. VoltNex Power can assist with sizing when you provide the load list and operating sequence.

VoltNex Power offers customized primary and secondary voltage configurations. Common primary voltages listed for the BK Series include 110V, 220V, 380V, 400V, 415V, 440V, 480V, 500V, 600V and 660V.

Common secondary control voltages include 12V, 24V, 36V, 48V, 110V, 120V, 220V and 380V, with special voltage combinations available for customized projects. Multi-tap and dual-voltage configurations can also be engineered according to the application.

For international OEM equipment, the primary and secondary voltages should be confirmed from the machine electrical schematic before ordering.

Yes. 24V, 110V and 220V are common control-voltage requirements, and the BK Series can be configured with different primary and secondary voltage combinations according to the project specification.

Typical applications include:

• 24V control circuits
• 24V relay and solenoid circuits
• 110V machine control circuits
• 110V lighting circuits
• 220V control circuits
• PLC and automation auxiliary power
• Contactor and motor starter circuits

Custom voltage ratios and multi-tap configurations are also available for OEM machine builders and control-panel manufacturers.

Yes. BK Series industrial control transformers are designed for applications including CNC machines, machine tools, lathes, milling machines, grinding machines, machining equipment and industrial automation systems.

They can provide dedicated control power for electrical control cabinets, contactors, relays, PLC systems, machine lighting, sensors, solenoids and auxiliary circuits.

For CNC equipment, the transformer should be selected according to the machine’s actual input voltage, control voltage, VA requirement, inrush load, frequency and available installation space.

Our control transformers are manufactured with Class B (130°C), Class F (155°C), or Class H (180°C) high-temperature insulation materials using Vacuum Pressure Impregnation (VPI) process to ensure moisture resistance, superior dielectric strength, low noise, and strict compliance with IEC 61558, EN 61558, and CE safety standards.

Yes. BK Series control transformers can be supplied with copper or aluminum windings depending on electrical requirements, cost targets and project specifications.

Copper winding is commonly selected when customers prioritize high conductivity, compact design and lower winding losses. Aluminum winding can provide a more cost-oriented solution for suitable industrial applications.

For OEM projects, VoltNex Power can specify the winding material according to the required current, temperature rise, efficiency, dimensions and budget.

The BK Series can be configured with Class B, Class F or Class H insulation systems, depending on the required thermal performance and application conditions. The page currently lists Class B/F/H options.

For industrial machinery and automation applications, insulation selection should consider ambient temperature, load profile, enclosure ventilation, duty cycle and required temperature rise.

For special environments such as high humidity, high altitude or high-vibration applications, customized construction can be discussed with the engineering team.

Yes. The BK Series is offered for 50Hz and 60Hz industrial power systems, making it suitable for machinery and OEM equipment intended for different international markets.

This is particularly useful for manufacturers exporting CNC machines, machine tools, automation equipment and electrical control panels to markets such as the United States, Canada, Europe, Australia, Latin America and the Middle East.

However, the exact voltage and frequency combination should always be confirmed against the transformer nameplate and technical specification before production.

Both transformer types can provide electrical separation between primary and secondary circuits, but their design priorities are different.

A control transformer is primarily intended to supply reliable power to control circuits containing loads such as contactors, relays, solenoids and other switching devices. Its design takes control-circuit inrush and voltage stability into consideration.

An isolation transformer is more commonly selected when the main objective is electrical isolation between circuits, equipment protection or power-quality-related applications.

For a machine control cabinet, a control transformer is generally the more application-specific choice when the load consists mainly of control components.

Yes. VoltNex Power provides OEM and ODM customization for industrial control transformer projects.

Customization can include:

• Primary/input voltage
• Secondary/output voltage
• VA/kVA capacity
• 50Hz / 60Hz frequency
• Copper or aluminum winding
• Class B / F / H insulation
• Multi-tap voltage
• Dual-voltage output
• Transformer dimensions
• Mounting-hole positions
• Terminal blocks
• Wiring configuration
• Enclosure integration
• Nameplate and branding

The transformer can be manufactured according to the customer’s electrical schematic, technical drawing, equipment specification or control-panel layout.

For an accurate quotation, provide as much of the following information as possible:

1. Primary voltage: e.g. 380V, 400V, 415V, 440V or 480V
2. Secondary voltage: e.g. 24V, 110V, 120V or 220V
3. Rated capacity: VA or kVA
4. Frequency: 50Hz or 60Hz
5. Phase: single-phase or three-phase, if applicable
6. Winding: copper or aluminum
7. Insulation: Class B, F or H
8. Application: CNC machine, machine tool, control cabinet, automation equipment, etc.
9. Installation: dimensions, mounting holes and terminal requirements
10. Quantity: sample, small batch, wholesale or OEM production

For custom projects, providing the electrical schematic or existing transformer nameplate can significantly speed up technical evaluation and quotation

Yes. VoltNex Power provides factory-direct BK Series industrial control transformer manufacturing and wholesale supply for OEM machine builders, distributors, electrical panel manufacturers, automation companies and industrial equipment integrators.

Standard and customized transformers can be supplied for projects in North America, Europe, Latin America, the Middle East, Asia-Pacific and other international industrial markets. OEM/ODM services can include custom electrical specifications, mechanical dimensions, nameplates, private labeling, packaging and volume production.

For bulk orders, customers can request a quotation based on model, VA/kVA capacity, voltage, quantity, customization requirements and destination market.