Victron Energy Autotransformer 120/240V-32A: The solution for stable voltage and maximum load balancing
The Victron Energy Autotransformer 120/240V-32A is a sophisticated power adapter designed to maximize the efficiency and flexibility of modern AC systems. Instead of generating energy itself, this device refines existing power sources through three core competencies: voltage increase (step-up), voltage reduction (step-down), and intelligent balancing of split-phase systems. It confidently solves typical problems such as load asymmetries and voltage incongruities that often occur with shore power connections or generators. This makes it the ideal energy solution for North American motorhomes, boats, and off-grid systems that require a stable and reliable power supply.
Morning at the campsite: the kettle is boiling for tea, the toaster is browning the bread, and you can still relax and use the hair dryer without risking a power failure. The autotransformer intelligently manages the weak shore power supply in the background so that your everyday life can continue without annoying compromises and fuse changes.
Voltage conversion and load balancing: the three core competencies
Three operating modes in one device:
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Step-up (voltage increase): Converts a 120V AC input voltage into a stable 240V AC output. Perfect for operators of off-grid systems who need to supply a 240V well pump or a large air conditioning system with their 120V inverter system.
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Step-down (voltage reduction): Generates a 120V AC output from a 240V AC source. This feature allows a standard North American 120V load distribution to be efficiently powered by a single, large 240V inverter.
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Split-phase generation & load balancing: Forms a 120/240V split-phase output with stable neutral from a 240V source and actively compensates for unbalanced loads so that the full power of the power source can be utilized.
Key performance data at a glance:
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Maximum continuous current: 32 A, which defines the rated power for continuous current.
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Continuous neutral conductor current: 28 A at 40°C, the true limit of the transformer's ability to actively compensate for load imbalance.
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Input/output voltage: Flexible for 120/240V at 50/60Hz.
That's the security of flipping the switch after a long, hot day and knowing that the 240V pump will reliably draw water from the well—even though your off-grid cabin only has a 120V system. The autotransformer invisibly bridges this gap, making essential comforts a matter of course.
Sophisticated design: Technical features for safety and efficiency
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Toroidal transformer: As the heart of the device, the toroidal transformer guarantees high efficiency, minimal no-load consumption, and quiet, trouble-free operation.
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Integrated circuit breaker: A multifunctional MCB (miniature circuit breaker) acts as the main switch and also provides reliable protection against overcurrent (32 A) and overheating.
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Intelligent grounding relay: This critical safety feature automatically establishes the neutral-to-ground connection during off-grid operation, which is essential for the correct functioning of ground fault circuit interrupters (GFCI) and is seamlessly controlled by a Victron MultiPlus/Quattro.
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Robust aluminum housing: The housing not only ensures durability, but also provides excellent heat dissipation.
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Secure connections: Large screw terminals (35 mm² / AWG 2) ensure a permanently secure electrical connection of the power cables.
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IP21 protection rating: The device is protected against solid foreign objects (>12.5 mm) and vertically falling dripping water, allowing for safe installation indoors or in protected areas.
In the middle of the night, a thunderstorm rolls in and the shore power at the harbor fails. You don't notice a thing, because your system seamlessly switches to battery power. Thanks to the intelligent grounding relay, which works perfectly with your Victron inverter, grounding remains ensured and all circuit breakers continue to function while you sleep undisturbed.
More than just a converter: the strategic advantage for your energy system
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Maximizing available power: Instead of using only a fraction of the rated power of your shore power or generator with an asymmetrical load, the autotransformer unlocks the full potential. This prevents premature tripping of circuit breakers and increases overall efficiency.
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Seamless and safe system integration: Automated control of the grounding relay by a Victron MultiPlus or Quattro system is an invaluable advantage. It guarantees standard-compliant and safe grounding in all operating conditions – a task that must be performed manually and is prone to errors in third-party systems.
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Efficient system architecture: Instead of complex stacking of two 120V inverters, the autotransformer allows the use of a single, often more efficient 240V inverter. This reduces costs, complexity, and potential sources of error in system design.
Today, you connect your system to a modern 50A outlet, and tomorrow to an old generator in the countryside. You don't have to reconfigure anything or worry – the power supply is simply there. This intelligent adaptability gives you the freedom to pursue your plans, knowing that your system is not only ready for the moment, but also for future expansions.
From camping to solar island systems: Versatile applications
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North American RV & marine systems: Perfect for vehicles and boats with 30A or 50A split-phase connections. The autotransformer balances the loads between the conductors (e.g., air conditioning vs. microwave), making the full connection power usable.
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Off-grid cabins and houses: Enables the operation of 240V high-consumption devices such as deep well pumps or tools in an inverter system primarily based on 120V – a crucial capability for true self-sufficiency.
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Alternative to stacked inverters: Provides a superior solution for generating a 120/240V split-phase output from a single 240V inverter, which is more powerful, simpler, and more cost-effective in cases of high asymmetry.
A boat owner in a remote cove runs his desalination plant while a family in an off-grid tiny house preheats the electric oven for dinner. Elsewhere, a craftsman connects a powerful welding machine in his mobile workshop. All these scenarios have one thing in common: a reliable, flexible power supply made possible by the autotransformer.
The Victron ecosystem: Recommended extensions for maximum control
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Victron MultiPlus or Quattro inverter/charger: These components are the key to full functionality. Not only do they control energy conversion, they also provide the crucial 24V signal to the autotransformer's grounding relay. This automated coordination ensures that the neutral-to-ground connection is only active in island mode – a must for safety and correct circuit breaker function, eliminating the need for manual configurations.
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Victron Cerbo GX & GX Touch Display: A Cerbo GX is the ideal addition to visualize the intelligent work of the autotransformer and to oversee the entire system. As a communication hub, it collects all performance data and visualizes it on a display or in the VRM portal. This allows you to see precisely how loads are distributed and power is optimized – valuable insights for even more efficient energy management.
32A vs. 100A model: Which autotransformer is right for you?
| Feature |
Autotransformer 32A |
Autotransformer 100A |
Significance for the user |
| Input circuit breaker / Max. through-current |
32 |
100 |
This is the only significant functional difference. The choice depends on the maximum 240V through load (e.g., for EV chargers). |
| Transformer balancing/neutral conductor current (continuous) |
28 |
28 |
The load balancing capability is identical for both models. The 100A model does not balance more current than the 32A model. |
| Transformer windings |
Identical |
Identical |
Confirms that the core component for power conversion and balancing is the same. |
| Typical application |
Systems with 30A/32A service, step-up/down applications, or as split-phase generators for inverters up to approx. 7.6 kVA. |
Systems with 50A+ service or when large 240V through loads need to be supplied. |
The 32A model is the more cost-effective and often entirely sufficient choice when high through-current is not required. |
From practice: Frequently asked questions from the community answered
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Why is my output voltage 117V on one conductor and 123V on the other, even without load? Is my device defective?No, according to Victron, this is normal and not a defect. The center tap of the transformer is not perfectly centered, but the voltage variation is within the tolerance of most standard devices.
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What voltage does the MultiPlus use to control the autotransformer's grounding relay?The control signal is 24V DC with very low current. Therefore, a thin cable (e.g., bell wire) is sufficient even for longer distances.
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Can I connect multiple autotransformers to a single inverter?Yes, but the inverter's grounding relay output can only directly control one autotransformer. For multiple devices, an auxiliary relay must be used, which is triggered by the inverter signal and then switches all autotransformers.
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Do I have to deactivate the internal grounding relay in my MultiPlus/Quattro?Yes, this is mandatory. If the autotransformer is operated at the output of the inverter, its internal relay must be deactivated to avoid faulty, double N-G connections in island mode.
Installation and configuration: Important information for safe operation
Safe and functional installation is crucial and should always be carried out by a qualified professional.
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Location selection: Mount the device in a dry, dust-free location. Ensure at least 10 cm of free space for optimal ventilation, with vertical mounting promoting heat dissipation.
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Cabling: Size the cables correctly in accordance with the 32A circuit breaker and local regulations to eliminate any fire hazard. Refer to the connection diagrams in the manual for the respective function.
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Grounding configuration: This is the most critical step. Ensure that the internal grounding relay of the feeding inverter (e.g., MultiPlus) is disabled and that the control terminals are correctly connected to the autotransformer.
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Avoiding errors: Never confuse the incoming neutral conductor from the source with the neutral conductor generated by the autotransformer in balancing mode. This is a common and critical installation error.
Conclusion: A strategic component for reliable energy systems
The Victron Energy Autotransformer 120/240V-32A is much more than just an accessory; it is an indispensable tool for building robust, reliable, and versatile AC energy systems. It elegantly solves the challenges of voltage conversion and load balancing and maximizes the performance of your power sources. As a product from the renowned manufacturer Victron Energy, known for the highest quality standards and durable system components, the autotransformer stands for absolute reliability. Victron underlines this confidence with a 5-year manufacturer's warranty that secures your investment in the long term.
Contact us for individual advice!
Technical data – Victron Energy Autotransformer 120/240V-32A (model ITR000100001) at a glance
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Model number: ITR000100001
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Input/output voltage: 120 / 240 V
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Frequency: 50 / 60 Hz
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Input circuit breaker: 32 A, two-pole
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Maximum 240V through current: 32 A
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Neutral conductor current, 30 min (peak): 32 A (3800 VA)
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Neutral conductor current, continuous: 28 A at 40°C
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Transformer type: Toroidal
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Housing material: Aluminum
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Electrical connections: Screw terminals 35 mm² / AWG (American Wire Gauge) 2
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Protection class: IP21 (Ingress Protection)
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Safety standard: EN 60076
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Weight: 12.5 kg
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Dimensions (H x W x D): 425 x 214 x 110 mm
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Grounding relay: Yes, controllable via MultiPlus/Quattro
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Warranty: 5 years
