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Variable Transformers iSA Series

Manual & Motorised Three Phase
Industrial Oil Immersed Variable Transformers 
150 to 800 Amps

iSA Series - Industrial
Three Phase Variable Transformers

380 to 415V three phase input oil-immersed manual & motor controlled variable transformers, delivering an output of 20V  up to 600V [1000V –X1000 Option].

As Magnetic Induction brushless designed solutions they are ideal for larger industrial-style applications.

To learn more please check out the listings below –


Proven & Endurable Design

As a Magnetic Induction based solution, iSA Variable Transformers utilise a simple, yet highly reliable, rotor and stator design principle to increase or reduce the magnitude of the voltage in a series transformer winding, thereby allowing the output voltage to vary.

The arrangement is similar to a motor, except that the rotor does not rotate continuously. Its maximum rotation is only 130 degrees. The magnetic coupling between the rotor (the shunt winding) and stator (series winding) will cause the magnitude of the voltage in the series winding to increase or decrease, depending on the angle or position of the rotor to the stator.

As standard models are offered as oil-immersed, however on request they can be supplied as air-cooled solutions [-AC Option].

Design Features

Operating System

Motorized (Auto) or manual with an electromagnetic brake.

Rugged Endurable Industry-Proven Design

Built to exacting mechanical tolerances, using the finest materials available, Setavolt™ iSA Series Variable Transformers have no carbon brushes and no moving parts to wear out.  They deliver a Maintenance Free and Hassle-Free performance. All winding and wirings utilise 99.9% pure copper EC grade materials.

Stepless Adjustable Output

iSA Series Variable Transformers deliver a step-less, distortion-free adjustable output voltage. The output voltage is typically adjustable from a few volts to over 100% of the input voltage.

High Overload Capability

Rated to support a 100% continuous loading, Setavolt™ iSA Series Variable Transformers are able to support a 150% overload situation for up to 100 seconds and a 200% overload up to 10 seconds.

Metering & Controls

All models are offered with digital output metering of the voltage and current. UP / Down Push Buttons enable output voltage selection.

International Standards Compliance & CE Certification

All Setavolt™ variable transformers are designed and manufactured to comply with all relevant International Standards and appropriate European Union CE Directives.


AmpsSetavolt ModelNominal
Volts AC
kVA @ max
Output Volts
W x H x D mm
150 AmpsiSA-150H380 – 415V15620 to 600V1300 x 1900 x 13002600
200 AmpsiSA-200H380 – 415V20820 to 600V1420 x 1900 x 14203400
300 AmpsiSA-300H380 – 415V31220 to 600V1510 x 1900 x 15103700
400 AmpsiSA-400H380 – 415V41620 to 600V1620 x 2000 x 16204000
500 AmpsiSA-500H380 – 415V52020 to 600V1620 x 2000 x 16204400
600 AmpsiSA-600H380 – 415V62420 to 600V1720 x 2220 x 17204700
700 AmpsiSA-700H380 – 415V72720 to 600V1820 x 2320 x 18204950
800 AmpsiSA-800H380 – 415V83120 to 600V1910 x 2320 x 19105100

Note: Other voltage configurations and higher-rated models are available on request/quotation.

Input Voltage:380V or 400V or 415V, Three Phase, 4 Wire – Customer to Specify
Output Voltage:20 – 600V Adjustable (No Load 20 – 720V)
[Option – 30 – 1000V Adjustable – X1000]
Power Factor:> 0.95
Efficiency:≥98% @ Full Load
Overload Capability:≤ 100% max. current rating continuous
≤ 150% max. current rating for 100 seconds
≤ 200% max. current rating for 10 seconds
Protection:Up/Down Over Limit – c/w 2 Stage Protection for Auto-Shutdown Protection
In the event of Up / Down limit failure auto shutdown
No Load Waveform Distortion:< 3%
Insulation Class:Class A
Cooling Type:Oil Immersed or an option Air-Cooled [-AC Option]
Audible Noise:< 65dBA at 1 meter
Environmental:Temperature range 0 to 40°C. Derate by 2% for each additional °C up to a max of 60°C
Suitable for indoor tropical use up to 95% RH (non-condensing)
Maximum altitude 1000m. Derate by 2.5% for each additional 500m
Construction:Enclosures to IP20 (NEMA 1 Style) BS EN5490 / IEV 60529
Standard Features:Digital Input Voltmeter, Output Voltmeter and Ammeter with Phase Selector Switch
UP/Down Push Buttons for Output Voltage Control and 
Remote Push Button Controller with 3-meter cable cord
Add-On Optional Accessories:Output 30 to 1000V [-X1000]
Air Cooled [-AC]
Field Power Source [-FPS]
– For DC Motor Blocked Core & Flux Testing Applications
Standards Compliance:BS EN 61558-1:2005 + AI:2009 & BS EN 61558-2-13:2009
CE Conformity:CE Marked – compliant with European Union Directive 2006/95/EC (Low Voltage Directive)
RoHS Compliance:Fully RoHS Compliant – complaint with European Union Directive 2011/65/EC (RoHS Directive)
Standard Warranty:1 Year / 12 months from date of supply

Sales & Support

Sales & Technical Data Sheet

– iSA-H (380-415V) Models 

Operator / User Manual

Operator Manual with sections on installation, and maintenance.

CE Certification 

iSA Series Three Phase Industrial Variable Transformers comply with the relevant European Union (EU) health, safety, and environmental protection directives and regulations and are duly CE marked.

Sinalda UK Declaration

Low Voltage Directive – 2006/95/EC

Sinalda UK Declaration

RoHS Directive – 2011/65/EC


If you do not find the Motorized Variable Transformer that meets your application’s exact needs, please contact us with your specific detailed requirements.