3-Phase Wye Buck/Boost Step-Down Transformer - 480V Wye Primary - 380Y/220 Wye Secondary - 781 Amps


Sale price$35,319.00




MT-BBT-480Y-380Y.220-3P-781A Buck and Boost Step-Down Transformer Ratings
Transformer Type: Buck/Boost Step-Down Autotransformer NRTL Listed for United States
Phase: Three Phase CSA Certified for Canada
Frequency: 50/60 Hz NEMA 3R Indoor/Outdoor Enclosure
Input Voltage: 480 V Wye Meets or Exceeds NEMA ST-20 Standards
Primary Amps: 625 A @ 480 V Wye Buck and Boost Step-Down Transformer
Primary Configuration: Delta
kVA: 519
Output Voltage: 380Y/220 V Wye
Secondary Amps: 781 A @ 380Y/220 V Wye
Voltage Difference: 79%
Winding Material: Copper
Knockouts: Side and Rear
Primary Termination: Front Access Copper Tabs or Lead Wires
Secondary Termination: Front Access Copper Tabs or Lead Wires
Cooling: Air / Dry Type
Insulation: 220°C
Temperature Rise: 150°C
Sound Level: 36 dB
Enclosure Rating: NEMA 3R
Encapsulation: Silica Sand & Resin Compounds
Enclosure Material: NEMA Type 3R Heavy Duty Ventilated
Finish: ANSI 61 Grey
Mounting: Floor Mount
Dimensions: 26.88"-L x 95.70"-W x 35.47"-H
Weight: 1,290 lb


Product Overview


3-Phase Wye Buck/Boost Step-Down Transformer - 480V Wye Primary - 380Y/220 Wye Secondary - 781 Amps

The MT-BBT-480Y-380Y.220-3P-781A Three Phase Step-Down Buck and Boost Transformer from Larson Electronics is powerful, reliable, and designed with the environment in mind. Suitable for both indoor and outdoor applications, the MT-BBT-480Y-380Y.220-3P-781A provides increased reliability, higher efficiency, protection against critical equipment failures, and an extra level of protection by isolating the power source from the connected device. The lower operating costs, lower heat emissions and lower cost of ownership make this transformer ideal for a wide range of applications and businesses.


Transformer Features: The MT-BBT-480Y-380Y.220-3P-781A buck and boost transformer is a three phase unit with a 519 kVA rating and a primary voltage of 480 V Wye using a maximum of 625 amps on the primary side. This step-down transformer has a secondary voltage of 380Y/220 V Wye and provides up to 781 amps available on the secondary side. Featuring robust construction, this unit's cores are manufactured with non-aging, cold-rolled silicon steel laminations using state of the art technology.

This unit boasts a low cost of ownership and is highly energy efficient. Lower heat emissions mean less cooling is needed as well. The NEMA 3R painted steel enclosure makes the unit suitable for both indoor and outdoor applications, and this step-down transformer can be floor mounted. The MT-BBT-480Y-380Y.220-3P-781A features a 220°C insulation with a 150°C temperature rise.

Construction: The copper winding in the MT-BBT-480Y-380Y.220-3P-781A are formed from high quality copper wire help to improve performance. The close tolerances used during manufacturing also eliminates burrs which hinder performance. Each core is specially coated to prevent the ingress of moisture and are electrically balanced to minimize axial forces during short circuit situations. Buck and boost transformers are designed to maximize the performance and life of electrical equipment. The MT-BBT-480Y-380Y.220-3P-781A is encapsulated in silica sand and resin, and cased in a NEMA 3R steel enclosure. NEMA 4, NEMA 4X, and NEMA 12 enclosures are available upon request.

Benefits: The MT-BBT-480Y-380Y.220-3P-781A buck/boost step-down transformer offers many benefits to the consumer. Buck/boost transformers pass the majority of the load voltage directly through the transformer, only transforming a small percentage of the load. Due to this technology, a smaller and quieter step-down transformer is manufacturered and uses less materials. This provides owners with significant energy savings as well as offering environmental benefits.

Higher efficiency not only extends the life of the transformer, but also turn into cost savings for owners in the form of lower energy bills and decreased cost of ownership. Installation and maintenance costs are reduced due to the smaller form factor, and less overall space requiorments are decreased. In addition, these step-down transformers operate quieter than a standard autotransformer of the same capacity.

Mounting: Integrated floor mounting brackets make installation fast and easy.

Installation: Installation is simple. Connect the primary leads and secondary leads to the step-down transformer per the provided wiring diagram. Knockout hubs on either side and the bottom of the transformer allow for easy line-in and line-out wiring. The front access cover provides convenient access.

Applications: Air conditioners, lighting systems, heating elements, motor applications and other applications that that require the ability to power loads that differ from the available line voltage.

Limitations: While there are many benefits to a buck/boost transformer, there are some limitations to consider. This transformer will only transformer voltage, it will not convert phases, it will not create even legs between line 1 and line 2 (L1 and L2 WILL be UNEVEN), has no circuit isolation, and does not create a neutral for applications where a neutral is not already present. If any of these limitations apply to you, you will need a standard transformer. Please see below link for our standard line of industrial transformers or our line of phase converters.

Note on Voltage Generation: Buck/boost transformers, like this unit, do NOT generate even legs of voltage on the secondary side. The generate voltage legs will always be unbalanced. This is acceptable for some situations, but other situations call for even legs on the secondary side. This simply cannot be achieved with a buck/boost transformer.

If your specific situation requires even legs of voltage on the secondary side, you will have to consider either a split phase buck/boost transformer or a standard industrial transformer. Larson Electronics has a wide range of both available for purchase:

Split Phase Buck/Boost Transformers

Standard Industrial Transformers

Note on Phases: This buck/boost transformer is a three phase step-up transformer. For single phase transformers, click on the following link:

Single Phase Delta Buck/Boost Transformers

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