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Multi-Tap Auto Transformers (208V, 240V, 400V, 480V, 600V)

Starting at $2,199.00

Adjust voltage using selectable taps to match your input and output requirements across multiple applications.

Used in CNC machines, industrial equipment, HVAC systems, pumps and compressors, and manufacturing equipment, including 208V, 240V, 480V, and 600V systems.

Built in partnership with Hammond Power Solutions for proven industrial performance.

Maximum Amps by Voltage
Transformer Size (KVA) 208v 240v 380/400v 480v 600v
9 25 21.7 13 10.8 8.66
15 41.6 36.1 21.7 18 14.4
30 83.3 72.2 43.3 36.1 28.9
45 125 108 65 54.1 43.3
75 208 180 108 90.2 72.2
112 312 271 162 135 108
150 416 361 216 180 144

Built and Supported in Wisconsin, USA

1 Year Warranty

Same-Day Replacement

Technical specifications for multi-tap three-phase auto-transformers:

Input Voltage

208V, 240V, 480V, 600V (Selectable)

Output Voltage

208V, 240V, 480V, 600V (Selectable)

KVA Ratings

9, 15, 30, 45, 75, 112, 150

Frequency

60 Hz

Transformer Type

Auto-Transformer

Cooling

Air-Cooled (Dry Type)

Enclosure

Type 3R / IP24 (Indoor / Outdoor Rated)

Certifications

UL & cUL Listed

Configuration Options

Delta-Delta, Wye-Wye (Learn More)

Dimensions & Weight

KVA

Weight

Dimensions (L × W × H)

9

161 lbs

6.94 × 15.19 × 15.13 in

15

170 lbs

6.94 × 15.19 × 15.13 in

30

205 lbs

20.2 × 19.38 × 21.5 in

45

310 lbs

25 × 23.9 × 28.75 in

75

520 lbs

21 × 26 × 38 in

112

685 lbs

21 × 26 × 38 in

150

930 lbs

21 × 26 × 38 in

Download Spec Sheets

Selectable Voltage Taps
Multiple taps allow you to select the input and output voltage needed for your application (208V, 240V, 480V, 600V).

Single Input / Output Operation
Only one input and one output voltage can be used at a time. For example, a 240V input can be configured to output 208V, 480V, or 600V, but only one output can be used at once.

Auto-Transformer Design
Uses a shared winding to convert voltage efficiently without electrical isolation.

Delta or Wye Configuration
Available in Delta-Delta or Wye-Wye configurations to match your system requirements. Learn More.

Application Use
Used for voltage adjustment in CNC machines, industrial equipment, HVAC systems, pumps and compressors, and manufacturing equipment.

This transformer is backed by a 1-year manufacturer’s warranty from Hammond Power Solutions. For support or questions, contact our team.

Download Warranty Document

Our Advantages

Why Choose American Rotary
Transformers

Same-Day Shipping

In-stock transformers ship fast so you can keep your operation running.

Trusted Industrial Quality

We partner with Hammond Power Solutions, a leading manufacturer of industrial transformers, to deliver reliable, high-quality performance in demanding environments.

Wide Range of In-Stock Options

From common voltage conversions to specialized applications, we stock a wide range of transformer configurations ready to go. If you don’t see what you need, we can source it.

Expert Sizing & Support

Choosing the right transformer matters. Our team helps you size and select the correct unit based on your equipment, voltage, and load requirements.

Talk to an Engineer

Customer stories

Real experiences from people who trust our products

My old rotary phase converter gave 30 years of faithful service before it went up in smoke. With customers asking when I’d be operational, I researched every manufacturer and the choice was clear on American Rotary. First impression when it ... READ MORE

FAA Certified Machine Shop Owner

  • Machining

Very good company to do business with. The salesman Lenny treated me like I was a big company. I was shopping for a roto phase for my home machine shop. He had all the time in the world for me. ... READ MORE

Rodney Mears

  • Machining

A quick google search pointed me toward American Rotary. It wasn’t their website or their pricing but the number of videos and testimonials about the quality of their product and the great service. I wasn’t disappointed. I called on a ... READ MORE

Carl DiPaolo

  • Machining

I purchased this unit for a tenant in a commercial property that needed 3 phase power and the cost for the utility company to bring it in was significantly higher with much longer times to complete the project. The phase ... READ MORE

Matt Peace

  • Metalworking

I tried an inexpensive digital converter that made my machine motors very hot due to unbalanced power. A person I bought a milling machine from said he had an American Rotary and was very happy with the quality, so I ... READ MORE

Brad Everett

  • Machining

When I started, the garage had a single 120 V receptacle behind a shelf. Now, there (4) duplex 120A receptacles, (1) NEMA 16,20 A 240/120V with a DPDT switch to select voltages. 30A 50A 1 phase receptacles. Two 20A, one ... READ MORE

Raymond Jensen

  • Agriculture

I called in a talked to a representative told them I have a refrigeration unit I was looking to run 3 phase to, gave them the specs and was recommended the ADX 10. I ordered it super fast shipping got ... READ MORE

Jonathan Arrington

  • Food Service

I had to move my workshop due to rent increases. The one I found didn’t have 3 phase. I found some cheap crappy digital shifter…didn’t work. Then I found American Rotary, they are the real deal! I am able to ... READ MORE

Mike Chinn

  • Woodworking

para todos los hispanohablantes America Rotary 100% recomendado fácil de instalar fácil de manejar fácil de cablear todo perfectamente gracias por su ayuda para poner en funcionamiento mi máquina edgebanding 3 Phase For all Spanish speakers, American Rotary 100% recommended. ... READ MORE

Neftaly Bustos Custom

  • Woodworking

Just got my ADX 5 up and running couldn’t be happier with my decision to purchase this excellent customer service and tech support. A++++++

... READ MORE

Mark Anderson

  • Metalworking

Absolutely love what american rotary does. Had a wonderful experience with their support team the phase converter we purchased and the transformer were supper easy to install definitely recommend buying from them. Customer service is 10/10

... READ MORE

Custom Machined Concepts | Andrey Girenko

  • Machining

American Rotary is an awesome company to work with, Mike was/is very helpful in answering my questions and getting me what I needed to get my shop ready for a new machine, giving me an option to either piggy back ... READ MORE

Charles Nelson

  • Machining

FAQs

Everything you need to know about getting the right power for your equipment.

Read all FAQs
What is a multi-tap auto-transformer?

A multi-tap auto-transformer allows you to select from multiple voltage options using taps to match your input and output requirements.

Select the input voltage available at your facility, then choose the output voltage required by your equipment. Refer to your equipment nameplate or contact our team for assistance.

No. Only one input and one output voltage can be used at a time based on the selected tap configuration.

Select the kVA based on your equipment voltage and total load. Use our sizing guide or contact our team to confirm the correct size.

Yes. Depending on how it is wired, it can be configured to step voltage up or down between the available tap options.
No. Auto-transformers use a shared winding and do not provide electrical isolation. Use an isolation transformer if separation is required.

Match the configuration to your system requirements. Learn more here. If unsure, we can help you confirm before ordering.

Many sizes are available for fast shipping. For current availability, call 888-743-6832 or contact our team.