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Special/Isolation/Control Transformers
20 Series · 2137 Models
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Special/Isolation/Control Transformers Overview
Isolation and control transformers provide galvanic separation for industrial automation and precision equipment. QDTB isolation transformers protect sensitive equipment from power disturbances. Control transformers deliver stable low-voltage power for PLCs and instrumentation. 0.1 kVA to 5,000 kVA, per IEC 61558.
Available Series
BK Series
The BK series represents single-phase control transformers designed for industrial control circuits, providing safe isolation and voltage transformation.
Triple-Freq Series
The TF series triple frequency transformers generate stable three-times frequency output for insulation testing of electrical equipment, including transformer cores and insulating materials. Dry-type design with Class F insulation ensures safe, repeatable test performance.
HF-High-Power Series
The HFPT series high frequency high power transformers are engineered for inverter and switching power applications, delivering efficient power conversion at high frequencies. Compact dry-type construction with Class F insulation suits modern power electronics systems.
BKC Series
The BKC series features enclosed single-phase control transformers, offering enhanced protection for control circuit applications.
VFS Series
The VFS series variable frequency supply transformers provide reliable voltage transformation for variable frequency power sources, supporting adjustable-speed drive and test systems. Dry-type construction with Class F insulation ensures stable operation across the frequency range.
EM-Controller Series
The EMC series electromagnetic filters suppress conducted electromagnetic interference in control and power circuits, ensuring compliance with EMC standards. Compact dry-type construction with Class F insulation provides effective filtering for sensitive equipment.
JMB Series
The JMB series is designed for lighting applications, providing safe voltage transformation for illumination systems.
1P-to-3P Series
The 1P-to-3P series phase-converting transformers enable three-phase equipment to operate from a single-phase supply, providing balanced three-phase output for motors and machinery. Dry-type construction with Class F insulation delivers dependable conversion.
Ozone-MF Series
The OZMF series ozone isolation transformers provide high-voltage isolation for ozone generation systems, delivering reliable stepped-up output for dielectric barrier discharge. Dry-type construction with Class F insulation ensures stable ozone generator performance.
High-Current Series
The HCG series high current rectifier transformers deliver the low-voltage, high-current output required for rectifier and electroplating applications. Dry-type construction with Class F insulation provides reliable, maintenance-friendly power conversion.
3P-to-1P Series
The 3P-to-1P series phase-converting transformers supply balanced single-phase power from a three-phase source, ideal for feeding single-phase loads from three-phase networks. Dry-type construction with Class F insulation ensures dependable conversion.
Vibration-EM Series
The VEM series pulse transformers deliver controlled pulse energy for vibration and electromagnetic applications, including electromagnetic exciters and pulsed power systems. Dry-type construction with Class F insulation provides reliable pulse performance.
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The values below are computed from what you selected above. Anything that cannot be computed yet is shown as an em dash — never as zero.
Iₙ = S / (√3·U) · I_sc = 100·Iₙ / uₖ · S_sc = √3·U·I_sc · I_p = k·Iₖ
Still required to complete the calculation: rated capacity S, impedance voltage uₖ, short-time or peak withstand current.
Per-model values (P0 / Pk / uₖ declared by the factory, losses, noise, temperature rise, dimensions, weight) are not in the product library: those rows stay at an em dash until the factory parameter sheet is supplied. An em dash means the value is unavailable — it is never rendered as zero.
Read-only: no price factor, not part of the sum — the loss-grade cost is already carried by the efficiency (subtype) base price, so charging here would double-bill. Values come from the product library type-test data, interpolated between published capacities; grades the library does not cover show an em dash, never zero.
特种/隔离/控制变压器（产品库逐型号 noLoadLoss，无独立能效档维度）
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Application Scenarios
Industrial Automation
Power isolation for PLC panels, CNC machines, and robotics.
Medical Equipment
Medical-grade isolation for surgical and laboratory instruments.
Precision Manufacturing
Power conditioning for semiconductor and metrology equipment.
Marine & Shipboard
Galvanic isolation between shore power and onboard networks.
Telecommunications
Control power for switching equipment and server racks.
Building Automation
Isolation for HVAC control and fire alarm panels.
Technical Advantages
Galvanic Isolation
Double-insulated winding with electrostatic shield.
Voltage Stability
Precision ratios for accurate secondary voltage.
Compact Design
Maximum power density saving panel space.
Global Standards
IEC 61558, UL 506, GB 19212 compliant.
FAQ - Special/Isolation/Control Transformers
What is the purpose of an isolation transformer?
How do I select the VA rating?
Can they handle harmonic loads?
What is the minimum order quantity (MOQ) for Special/Isolation/Control Transformers?
What is the delivery time for Special/Isolation/Control Transformers?
Which standards and certifications do your Special/Isolation/Control Transformers comply with?
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Isolation vs Control vs K-Rated: How to Choose
| Isolation Transformer (1:1) | Control Transformer (Step-Down) | K-Rated Isolation | |
|---|---|---|---|
| Winding ratio | Primary and secondary at the same voltage, forming a 1:1 barrier | Steps the line voltage down to the control bus voltage | Usually 1:1, but sized for the harmonic content of the load |
| Function | Breaks the galvanic path to stop noise and ground faults reaching the load | Holds a steady voltage for contactors, relays and PLC supplies | Feeds non-linear loads without overheating the core |
| Load type | Sensitive instruments, medical and laboratory equipment | Control panels, instrumentation and machine tools | Drives, rectifiers, IT and LED-heavy distribution boards |
| Core & winding | Electrostatic shield fitted between primary and secondary | Standard core with windings chosen for low regulation | Core sized for harmonic flux, released as a K-factor rating |
| Inrush behaviour | Inrush set by the core design, with soft-start options available | Inrush must be covered by the upstream breaker | Harmonic current lifts the effective load current |
| Mounting | Floor, wall or panel mount depending on rating | Panel or DIN rail at small ratings | Panel or floor mount with ventilation clearance |
| Typical application | Medical locations, marine and telecom sites | Industrial automation and building services panels | Plants with VFD and rectifier loads |
Where QDTB® Isolation & Control Transformers Are Specified
Every machine tool, robot cell and process skid that carries a PLC or a servo drive needs a control transformer to hold the coil and electronics supply steady while the main bus dips. An isolation unit goes one step further and breaks the galvanic path, which is what protects instrumentation from common-mode noise and from ground potential differences across a large plant.
Medical locations and shipboard panels specify isolation transformers because the load cannot tolerate a first fault to earth: the isolated secondary keeps the equipment running until the fault is traced. Marine and offshore panels add the same requirement on top of vibration and salt-air duty, which is why the winding and impregnation are specified rather than assumed.
Telecom sites, building automation panels and precision manufacturing lines use the smaller ratings as panel-mount units, while steel plants and test laboratories take the high-current designs. Where the load is a bank of drives or rectifiers, the K-rated version is specified so the extra harmonic flux does not overheat the core.
Units are designed and tested to IEC 61558 and its GB mirror standards, with IEC 60076, IEEE C57 / ANSI C84.1 and GB/T 1094 cited on the datasheet for custom and higher-power designs. Nameplate data, routine test reports and the type test certificates travel with the shipment, which is what the panel builder files for the installation inspection.
Frequently Asked Questions
What is the purpose of an isolation transformer?
Galvanic separation protecting equipment from noise, spikes, and ground faults. Creates new reference ground eliminating ground loops.
How do I select the VA rating?
Total connected VA plus inrush currents, add 25% margin. Available 0.1 kVA to 5,000 kVA.
Can they handle harmonic loads?
Yes, K-factor rated transformers (K-4, K-13, K-20) for non-linear loads.
What is the minimum order quantity (MOQ) for Special/Isolation/Control Transformers?
One unit for standard products. Custom-designed equipment is quoted on specifications — send your parameters or drawings and our sales team will confirm the MOQ for your configuration.
What is the delivery time for Special/Isolation/Control Transformers?
Standard units are delivered in 30-45 days. Custom or large-capacity units follow a project-specific schedule confirmed at quotation. Rush orders can be accommodated for urgent projects.
Which standards and certifications do your Special/Isolation/Control Transformers comply with?
They are designed and tested to IEC 60076, IEEE C57 / ANSI C84.1, GB/T 1094. All QDTB® equipment is ISO 9001 certified and CE marked, and the company operates ISO 9001, ISO 14001 and ISO 45001 management systems.