150KVA Dry Type Isolation Transformer

GUANGBIAN manufactures this 150KVA Dry Type Isolation Transformer for applications requiring electrical isolation and low-voltage distribution. The unit shown here was built for a construction project in Saudi Arabia and is configured with a stainless-steel enclosure, IP43 protection, full copper windings, Delta-Star (Δ-Y) connection, automatic fan cooling, and two additional MCCBs.

The low-voltage side provides 400V three-phase and 230V single-phase power. This allows three-phase construction equipment and single-phase auxiliary loads to be supplied from the same transformer, subject to the site's load calculation and electrical distribution design.

Configuration for 400V and 230V Loads

The 400V three-phase supply can be used for equipment such as cranes, concrete mixers, welding machines, pumps, and other three-phase machinery. The 230V supply is suitable for lighting, office equipment, portable tools, air-conditioning units, and other single-phase loads.

For a construction site, using one transformer for both types of loads can simplify the distribution arrangement. The 150 kVA rating, however, does not mean that every connected load can operate simultaneously at full nameplate power. Transformer selection should consider the site's maximum demand, motor starting current, load factor, power factor, and the expected combination of loads.

The transformer uses full copper windings. Copper has lower electrical resistivity than aluminum, so conductor losses can be controlled through appropriate conductor sizing and winding design. For installations in hot climates, the winding material is only one part of the thermal design; ambient temperature, insulation system, ventilation, loading, and cooling method also need to be considered.

The Delta-Star (Δ-Y) connection is used for the primary and secondary windings. The Star-connected low-voltage side provides a neutral point for the 230V single-phase supply, while the Delta winding provides a path for triplen harmonic currents to circulate within the winding. The neutral grounding arrangement should follow the project's electrical design and applicable local requirements.

Cooling and Enclosure

Temperature sensors are used to monitor the winding temperature. When the preset temperature is reached, the automatic cooling fans start to increase heat dissipation. This is useful for installations where the load changes during operation or where the ambient temperature is relatively high.

The enclosure is made from stainless steel and has an IP43 rating. According to IEC 60529, the first digit of IP43 indicates protection against solid foreign objects larger than 1 mm, while the second digit indicates protection against water spray under the conditions specified for IPX3. The rating provides protection for the intended installation environment but should not be interpreted as fully dust-tight or waterproof.

For outdoor or partially exposed construction sites, the installation should still provide appropriate protection from direct heavy rain, standing water, excessive dust accumulation, and other conditions outside the enclosure's specified protection level.

Technical Details and Project Selection

The two additional MCCBs provide separate downstream circuit protection and isolation. Their ratings should be selected according to the connected equipment, cable size, expected current, and protection coordination requirements. They are particularly useful where different groups of construction loads need to be connected to the transformer.

Before production, the required input voltage, output voltage, frequency, phase configuration, load type, ambient temperature, enclosure requirements, grounding arrangement, and applicable electrical standard should be confirmed. Motor-driven equipment should also be identified because starting current can affect transformer sizing even when the normal running load appears to be within 150 kVA.

Manufacturing, Testing and Customization

GUANGBIAN manufactures 150KVA Dry Type Isolation Transformer according to the electrical specification of each project. For this configuration, the main requirements include the 150 kVA capacity, 400V/230V secondary distribution, copper windings, Delta-Star connection, IP43 enclosure, automatic fan cooling, and additional MCCBs.

Other specifications can be changed when required, including input and output voltage, frequency, winding arrangement, enclosure design, cooling method, and protection configuration. The final design is based on the electrical system and installation conditions rather than using the same configuration for every project.

Factory testing is carried out according to the agreed technical specification and applicable standard. Test records and third-party inspection can be arranged when required by the project.

FAQ

What is the output voltage of this transformer?

This configuration provides 400V three-phase and 230V single-phase output. Other voltage combinations can be manufactured according to the project requirements.

Can 400V and 230V loads be supplied by the same transformer?

Yes. The Delta-Star connection provides a three-phase secondary supply and a neutral point for single-phase distribution. The connected loads must be properly distributed and remain within the transformer's rated capacity.

How is the cooling fan controlled?

Winding temperature sensors monitor the operating temperature. When the preset temperature is reached, the control system starts the cooling fans. The control temperature is set according to the transformer's thermal design.

What does IP43 mean?

IP43 indicates protection against solid foreign objects larger than 1 mm and protection against water spray under the IPX3 test conditions. It is not a fully dustproof or waterproof enclosure.

Is 150 kVA suitable for a construction site?

It depends on the actual load. The calculation should include normal operating current as well as motor starting current, welding loads, simultaneous operation, and other temporary peak loads. The transformer capacity should be confirmed from the project's load schedule rather than from the number of connected machines alone.

Can the transformer be made to other specifications?

Yes. Input and output voltage, frequency, connection configuration, enclosure, cooling, and protection requirements can be specified according to the project. The complete electrical specification should be confirmed before production.