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Application Notes

VARIACs <> VARIABLE TRANSFORMERs
Industrial Adjustable Variable Voltage Autotransformers

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Variable Transformers, often generically referred to as "Variacs", are widely used when adjustable voltages are required for quality control testing, electronic equipment burn-in, life-tests, low voltage performance evaluation, D.C. rectifier/regulator analysis or other engineering applications.

These application notes for Variacs present some of the uses for which this versatile industrial work horse is uniquely suited. If you are aware of other applications, please forward us a note with details. At the conclusion of these application notes is a link permitting you to refer this page to an interested colleague.

Output voltage adjustment or variacs and variable transformers is normally accomplished manually, with a simple control knob. However, motorized control is also available for remote adjustment.

Variacs are also frequently used to adjust temperature, control lighting, hot wire cutting operation control, for motor speed control and for testing equipment operation to simulate over-voltage or under-voltage conditions.

Audio enthusiasts report improved sound quality when line voltage to amplifiers is reduced to about 100 to 112 Volts ! !
Some audio devotees have installed voltage regulators together with Variable Transformers for constant lowered  voltage.

When variable transformers are combined with ferroresonant voltage regulators, a well regulated, wide range AC voltage source can be achieved. Also, variacs couples with isolation transformers can be employed to "isolate" sensitive equipment from AC power Line electrical noise and interference.

In engineering and equipment service environments isolation transformers are also utilized for personnel safety in addition to providing variable voltages for testing purposes.

Variacs combined with isolation transformers can be used for any of the engineering, testing or control functions described above to provide interference or ground noise isolation.

Stepper motor controlled variable transformers, combined with a feedback controller, has been effectively employed to regulate output voltage.  Effects of AC power input variations are effectively eliminated.

400 Hz Variacs find wide application in military and aeronautical engineering endeavors because of their small size and light weight. Because of these demanding applications, 400 Hz variacs are engineered to exhibit superior resistance to high temperatures, humidity, altitude and shock / vibration. View available 400 Hz units.

Summary of common Variable Transformer / Variac applications

Some Engineering, Test and Maintenance facilities require Variable Transformers capable of handling 50, 60 and 400 Hz power.  Link to Multi-Frequency Variable Transformers to check out available units.

In Summary, Variacs and Variable Transformers,  are widely used when adjustable voltage is required for quality control testing, electronic equipment burn-in, life-tests, low voltage performance evaluation, D.C. rectifier/regulator analysis or other engineering applications. This ap-note demonstrates useful applications for Variacs / Variable Transformers

Please recommend this Application Note to an Associate

VARIACs <> VARIABLE TRANSFORMERs
Industrial Adjustable Variable Voltage Autotransformers

Some Models in Rectangular Metal Case	Precise, continuous voltage control 60 Hz and 50/60 Hz Models available Bench-Top and Panel-Mount Models Motorized Models can be factory ordered 120 Volt and 240 Volt Models Three-Phase Models can be Special Ordered Autotransformer design gives voltage boost Now Available !  400 Hz Variacs ... See 'em Here Check Out ... 3-Phase Variable Transformers
Bench Top Models 120 Volt Models 240 Volt Models		Panel Mount Models 120 Volt Models 240 Volt Models

Variable Transformers, often generically referred to as "Variacs", are widely used when adjustable voltages are required for quality control testing, electronic equipment burn-in, life-tests, low voltage performance evaluation, D.C. rectifier/regulator analysis or other industrial and engineering applications.

Bench Top units, employing a AC power line cord and electrical outlet, can be conveniently moved within the engineering laboratory or equipment service area to provide adjustable voltage.

Panel mount units are often incorporated into test equipment or permanent installations.

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400 Hz Variacs - -
contact Electronic Specialists to discuss requirements and availability
delivery time is usually 3 to 6 weeks After Receipt of Order
View details on available 400 Hz Variac models

Three-Phase Models - -

We have cataloged the most popular of our 3-Phase Variable Transformers . . See them Here

Contact Electronic Specialists to discuss requirements and availability
delivery time is usually 4 to 6 weeks After Receipt of Order and Payment
Payment in full required at time of order, as these are Specially Constructed

Motorized Models - -
contact Electronic Specialists to discuss requirements and availability
delivery time is usually 4 to 6 weeks After Receipt of Order and Payment
Payment in full required at time of order, as these are Specially Constructed

Check Out Electronic Specialists Variac controlled voltage regulator and isolation transformer
Have a look at our Precision, Variac Voltage Regulator  packages
New ! Stepper Motor Variac Regulator Controller

FREE Variac / Variable Transformer Tutorial More Insight on Variable Transformers & Applications

View our 400 Hz Variac units

Don't Miss Winter Sale - - Big Discounts on Several Popular Variable Transformer Models

Variac is a Registered Trademark of Power Designs / Variac

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Studies Show ...................

Winter Storms Cause More 
Wild Power, phone line outages, surges, spikes and interference
than Summer Storms

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Ferroresonant Voltage Regulators Precision Variac Voltage Regulators ....... Stepper Motor Voltage Regulators ......Hi-Power Voltage Regulators	Modem Speed-up & Telecommunications Protection Systems RJ-11, RJ11, RJ-21, RJ21, RJ-45, RJ45 Screw Terminals <>  Wire-In <> DSL	Cable Modems W-4b Speed-up, Isolation, Intermittent Cable Sync Fix, & Protectors Systems
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AC Power Line Protection  220-250 Volts ...... Commercial ... Industrial and .. Laboratory & Basic Grades  NEMA  6-15, 615, 6-20, 620	Direct Plug AC Power Protection with built in Modem Protector Dual Function - Direct Plug AC Power and Modem Protectors	Dual Function - Direct Plug AC Power and Network Protectors
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Variable Voltage  ....... Regulators  ....... Isolation Transformers ....... Variacs  ....... 400 Hz Variacs	Industrial & Copier Hi-Current Filter-Suppressors AC Hi Power Protection NEMA 14-20, 1420, 14-30, 1430, 14-50, 1450	Cable Modem <> Speed-up, Isolation & Protection System
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Electronic Specialists regularly supplies Regulation, Suppression and Protection Products 
for 100, 110, 115, 117, 120, 125/250, 120/208, 220/380, 277/480 Volts 
single, dual and 3-phase systems 

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