Why Choose the ETE MV100P3S3 100 VA Multi-Voltage Control Transformer?
The ETE MV100P3S3 is a versatile 100 VA single-phase multi-voltage industrial control transformer designed to accommodate 120 V AC or 240 V AC primary supplies and provide a selectable 12 V AC or 24 V AC secondary output. Manufactured by Eastern Transformers & Equipment (ETE), this transformer belongs to the established ETE MV multi-voltage stock control transformer range, developed for electrical panel builders, machinery manufacturers and industrial automation applications requiring flexible voltage configurations.
The MV100P3S3 features two 0/120 V primary windings and two 0/12 V secondary windings. By connecting the primary windings in parallel, the transformer can operate from a nominal 120 V AC supply. Connecting the primary windings in series allows operation from a nominal 240 V AC supply. This arrangement enables a single transformer model to accommodate two commonly used control supply voltages.
On the secondary side, the two 12 V windings provide additional flexibility. When connected correctly in parallel, they provide a nominal 12 V AC output with the combined winding current capability. When connected correctly in series, they provide a nominal 24 V AC output. This makes the MV100P3S3 a practical solution for control panels and machinery incorporating compatible 12 V AC or 24 V AC equipment.
With a 100 VA rated apparent power, Class E insulation and 12% voltage regulation, the MV100P3S3 provides a flexible AC control power solution. Its compact dimensions of 85 × 70 × 93 mm and weight of 1.5 kg make it suitable for installation planning in electrical cabinets where space is limited.
The transformer is specified with EPH 1 or EPN 1 enclosure references in the ETE Stock Control Transformer Range, March 2026. Its dual-primary and dual-secondary winding arrangement offers particular value to OEMs seeking to standardise transformer selection across equipment with different supply and control voltage requirements.
Key Advantages
- Dual primary voltage capability: Suitable for 120 V AC or 240 V AC supplies using the correct winding configuration.
- Selectable secondary voltage: Provides 12 V AC or 24 V AC through appropriate secondary winding connections.
- 100 VA rated apparent power: Suitable for appropriately sized industrial control and auxiliary circuits.
- Parallel primary connection: Two 120 V windings can be connected in parallel for a nominal 120 V AC supply.
- Series primary connection: Two 120 V windings can be connected in series for a nominal 240 V AC supply.
- Parallel secondary connection: Two 12 V windings can be connected in parallel to provide a nominal 12 V AC output.
- Series secondary connection: Two 12 V windings can be connected in series to provide a nominal 24 V AC output.
- Flexible OEM integration: Helps reduce the need for separate fixed-voltage transformer variants.
- Class E insulation: Provides the specified electrical insulation classification.
- 12% voltage regulation: Offers a defined regulation characteristic for control circuit design.
- Compact construction: Measures 85 × 70 × 93 mm.
- Low installation weight: Weighs 1.5 kg.
- Industrial control applications: Suitable for compatible control panels, machinery and auxiliary circuits.
- Enclosure references: EPH 1 or EPN 1.
Key Features
- ETE MV multi-voltage control transformer series.
- 100 VA rated apparent power.
- Single-phase transformer configuration.
- Dual 0/120 V primary windings.
- Primary terminal arrangement: 0/120 V + 0/120 V.
- 120 V AC primary operation: Parallel winding connection.
- 240 V AC primary operation: Series winding connection.
- Dual 0/12 V secondary windings.
- Secondary terminal arrangement: 0/12 V + 0/12 V.
- 12 V AC output: Parallel secondary connection.
- 24 V AC output: Series secondary connection.
- 50/60 Hz rated operating frequency.
- Continuous-rated control circuit transformer.
- Class E electrical insulation.
- 12% specified voltage regulation.
- IP20 touch-proof terminals.
- Class H varnish-impregnated windings.
- Transformer core earth connection.
- 85 × 70 × 93 mm overall dimensions.
- 1.5 kg specified weight.
- EPH 1 or EPN 1 enclosure references.
Understanding the 120 V and 240 V Dual Primary Connections
The ETE MV100P3S3 uses two separate primary windings, each rated for a nominal 120 V AC. This arrangement allows the transformer to be configured for either a 120 V AC or 240 V AC input without changing the transformer itself. The required configuration is determined by how the two primary windings are connected.
For a nominal 120 V AC supply, the two primary windings are connected in parallel. Both windings operate at the same applied voltage, with the total primary current shared between them when connected correctly.
For a nominal 240 V AC supply, the two primary windings are connected in series. In this configuration, the applied voltage is distributed across the two windings so that each operates at its intended nominal voltage.
Important: Series and parallel winding connections must be made with the correct polarity and terminal identification. Incorrect wiring can cause excessive current, incorrect output voltage or transformer damage. The manufacturer's wiring diagram must be followed, and the installation should be completed by a suitably qualified person.
Selectable 12 V AC or 24 V AC Secondary Output
The MV100P3S3 also incorporates two secondary windings, each providing a nominal 12 V AC. These windings can be connected in either series or parallel, allowing the transformer to supply compatible equipment requiring different low-voltage AC control supplies.
For a nominal 12 V AC output, the secondary windings are connected in parallel. When correctly connected with matching polarity, the output voltage remains 12 V AC while the winding current capabilities are combined.
For a nominal 24 V AC output, the secondary windings are connected in series. The voltage contributions of the two 12 V windings add together, producing a nominal 24 V AC output.
This flexibility is useful for OEM machinery and electrical control panels where the same transformer design may be required to support either 12 V AC or 24 V AC control equipment. The correct secondary configuration should be selected during installation and verified before connecting the load.
100 VA Output Capacity and Calculated Secondary Current
The 100 VA apparent power rating applies to the transformer as a whole, not independently to each secondary winding. When the secondary windings are correctly connected in parallel for a nominal 12 V AC output, the calculated total full-load current is approximately 8.33 A.
When the secondary windings are correctly connected in series for a nominal 24 V AC output, the calculated full-load current is approximately 4.17 A.
These figures are derived from the transformer's 100 VA rating and the relevant nominal secondary voltage. They are calculated values for load assessment rather than independent confirmation of terminal current ratings or overcurrent protection requirements.
The transformer's 12% voltage regulation should also be considered when assessing connected equipment. Actual secondary voltage may vary between no-load and rated-load conditions, and the total connected load should remain within the applicable transformer rating.
Typical Applications
- Industrial electrical control panels requiring a 12 V AC or 24 V AC supply.
- OEM machinery designed for 120 V AC or 240 V AC primary supplies.
- Electrical panel-building projects requiring series and parallel winding flexibility.
- Factory automation and industrial process control equipment.
- AC relay and contactor control circuits with compatible voltage requirements.
- Industrial switching and auxiliary electrical circuits.
- Packaging, processing and manufacturing machinery.
- Machine control cabinets using configurable AC control voltages.
- Compatible 12 V AC or 24 V AC indicators and control devices.
- Electrical control assemblies where one transformer model supports different voltage configurations.
- Maintenance and replacement applications requiring a compatible 100 VA multi-voltage transformer.
- Compact industrial panels where transformer size and weight are important.
Installation and Winding Connection Considerations
Before installing the ETE MV100P3S3, confirm the available primary supply voltage, required secondary output voltage and total connected apparent power. The transformer must be configured using the correct primary and secondary winding arrangements.
For 120 V AC primary operation, connect the two 120 V primary windings in parallel according to the manufacturer's wiring diagram. For 240 V AC primary operation, connect the windings in series according to the same instructions.
For a 12 V AC secondary output, the two 12 V windings must be connected in parallel with the correct polarity. For a 24 V AC secondary output, they must be connected in series with the correct polarity so their voltages add rather than oppose one another.
Appropriate primary and secondary circuit protection, protective earthing, conductor sizing, ventilation and mechanical mounting should be incorporated into the installation design. The specified EPH 1 or EPN 1 enclosure references should be checked where additional physical protection is required.
