ETE MV500P2S3 500 VA Multi-Voltage Control Transformer – 12 V / 24 V AC Output
The ETE MV500P2S3 is a 500 VA single-phase multi-voltage industrial control transformer featuring a tapped primary winding and two nominal 12 V AC secondary windings. Part of the ETE MV stock control transformer range, this model provides flexible AC control power for compatible industrial electrical panels, OEM machinery and automation systems.
The transformer features 20/0/380/420 V primary terminals and 0/12 V + 0/12 V secondary terminals. Its two secondary windings can be connected in parallel to provide a nominal 12 V AC output or in series to provide a nominal 24 V AC output. This makes the MV500P2S3 a practical option for electrical designers working with different low-voltage AC control requirements.
The MV500P2S3 also includes a 20 V primary adjustment tap. The correct function of this tap and its approved terminal connections must be confirmed with ETE. The primary terminal markings should not be used alone to determine the wiring arrangement.
With a 500 VA apparent power rating, Class E insulation and 8% voltage regulation, the MV500P2S3 is suitable for consideration in industrial control applications with appropriately rated electrical loads. It measures 120 × 120 × 120 mm and has a specified weight of 6.2 kg.
The transformer is listed in the ETE Stock Control Transformer Range, March 2026, with enclosure references of EPH 3 or EPN 2.
Key Advantages
- Selectable 12 V or 24 V AC output: Supports two nominal low-voltage AC control configurations.
- 500 VA rated capacity: Provides an apparent power rating suitable for appropriately sized industrial control loads.
- Tapped primary winding: Features 20/0/380/420 V terminals.
- Primary adjustment provision: Includes a 20 V adjustment tap, with connections requiring ETE confirmation.
- Dual secondary windings: Two separate nominal 12 V AC windings.
- Parallel secondary connection: Provides a nominal 12 V AC output.
- Series secondary connection: Provides a nominal 24 V AC output.
- Flexible OEM integration: One transformer model can accommodate either supported secondary configuration.
- Class E insulation: Specified insulation classification.
- 8% voltage regulation: Defined regulation characteristic for control circuit design.
- Industrial dimensions: Measures 120 × 120 × 120 mm.
- Specified weight: 6.2 kg.
- Enclosure references: EPH 3 or EPN 2.
- Stock range identification: Listed as MV500P2S3 in the March 2026 ETE price list.
Key Features
- ETE MV multi-voltage control transformer series.
- 500 VA rated apparent power.
- Single-phase transformer configuration.
- 20/0/380/420 V primary terminal arrangement.
- 20 V primary adjustment tap.
- 0/12 V + 0/12 V secondary terminal arrangement.
- Two nominal 12 V AC secondary windings.
- 12 V AC parallel secondary output.
- 24 V AC series secondary output.
- Class E insulation system.
- 8% specified voltage regulation.
- 120 × 120 × 120 mm overall dimensions.
- 6.2 kg specified weight.
- EPH 3 or EPN 2 enclosure references.
- Part of the ETE stock control transformer range.
Understanding the Tapped Primary and 20 V Adjustment Connection
The ETE MV500P2S3 has a tapped primary winding with terminals marked 20/0/380/420 V. This arrangement is intended for compatible AC supply configurations using the appropriate manufacturer-approved connections.
The 20 V primary adjustment tap forms part of this winding arrangement. Its exact purpose and the approved terminal combinations must be confirmed with ETE before the transformer is energised. The 20 V marking must not be treated as evidence of an independently rated 20 V primary input.
Electrical designers should verify the intended supply voltage and primary terminal arrangement against the manufacturer's wiring diagram. Incorrect primary connections can result in an unsuitable secondary voltage, excessive current or equipment damage.
Selectable 12 V AC or 24 V AC Secondary Output
The MV500P2S3 incorporates two separate 0/12 V secondary windings. These windings provide flexibility for industrial control circuits requiring either a nominal 12 V AC or 24 V AC supply.
12 V AC Parallel Secondary Connection
When the two secondary windings are correctly connected in parallel, the nominal output voltage remains at 12 V AC. Parallel operation allows the windings to share the connected load within the transformer's overall 500 VA rating.
Correct winding polarity is essential. Incorrect parallel connections can create excessive circulating current, overheating or transformer damage. The manufacturer's approved terminal connections must always be followed.
24 V AC Series Secondary Connection
When the two secondary windings are correctly connected in series, their nominal voltages add together to provide 24 V AC.
The series connection must use the correct winding polarity so the two 12 V outputs add rather than oppose one another. The ETE wiring diagram should be used to establish the appropriate connections.
The 12 V and 24 V options are alternative configurations of the same transformer, not two independent 500 VA supplies.
500 VA Output Capacity and Calculated Secondary Current
The ETE MV500P2S3 has a total rated apparent power of 500 VA. The nominal current corresponding to each secondary voltage can be calculated using:
Current (A) = Apparent power (VA) ÷ Secondary voltage (V)
Calculated Current at 12 V AC
For a correctly connected 12 V AC parallel output:
500 VA ÷ 12 V = approximately 41.67 A
This is the calculated total current corresponding to the complete transformer rating at 12 V AC. It does not independently establish the manufacturer's permissible terminal or winding current ratings.
Calculated Current at 24 V AC
For a correctly connected 24 V AC series output:
500 VA ÷ 24 V = approximately 20.83 A
This is the calculated current corresponding to the complete transformer rating at 24 V AC.
The connected load must remain within the applicable transformer and winding ratings. Engineers should also assess the operating characteristics, inrush requirements and appropriate circuit protection for connected equipment.
What Does 8% Voltage Regulation Mean?
The ETE MV500P2S3 has a specified 8% voltage regulation. Voltage regulation describes the change in secondary voltage between no-load and rated-load conditions under defined operating or test conditions.
The actual secondary voltage may vary with the applied primary supply and connected load. The nominal 12 V AC and 24 V AC outputs should not be interpreted as electronically stabilised voltages.
When selecting the transformer for voltage-sensitive equipment, engineers should consider its regulation characteristic and the expected variation in the primary supply.
Typical Applications
- Industrial electrical control panels requiring 12 V AC or 24 V AC.
- OEM machinery incorporating configurable low-voltage AC control circuits.
- Factory automation and industrial process control equipment.
- Electrical panel-building projects requiring dual secondary windings.
- Compatible AC relay and contactor control circuits.
- Industrial switching and auxiliary electrical assemblies.
- Packaging, manufacturing and processing machinery.
- Machine control cabinets requiring a dedicated AC transformer.
- Compatible 12 V AC or 24 V AC indicators and control devices.
- Electrical installations requiring series or parallel secondary winding configurations.
- Maintenance and replacement applications requiring a compatible 500 VA multi-voltage transformer.
- Control panels where the 20 V primary adjustment tap is required and its connections have been confirmed with ETE.
Installation and Connection Considerations
Before installing the ETE MV500P2S3, confirm the available primary supply, required secondary voltage, total connected apparent power and correct terminal connections.
Primary wiring: The 20/0/380/420 V terminals include a 20 V adjustment tap. Confirm the approved primary terminal connections with ETE before energising the transformer.
Secondary wiring: The two 0/12 V secondary windings must be connected in parallel for a nominal 12 V AC output or in series for a nominal 24 V AC output. Correct winding polarity is essential in both configurations.
Suitable primary and secondary circuit protection, conductor sizing, protective earthing where applicable, ventilation and secure mechanical mounting should be incorporated into the installation design.
The specified EPH 3 or EPN 2 enclosure references should be checked against the intended installation requirements. The references alone do not establish an enclosure protection rating or confirm that an enclosure is included.
