Nowadays, the importance of variac transformers are often overlooked. What people don’t know is that variac has been the saving grace for humans in unnoticeable ways.
For instance, it compensates a low AC voltage for a musician’s guitar, which runs poorly at a venue. Also, it helps a cinematographer to adjust lightings on a movie set for a better filming experience.
Variacs are efficient, sturdy, and easy-to-use necessary tools. But, what the heck is a variac? In this article, we will help you understand the nature of variac – its purpose, and its uses.
What are Variable Transformers?
Variacs, or commonly known as variable autotransformers, generally produce and transform the differing amount of voltage from the same input voltage, wasting only minor core and copper losses.
Variacs have different trademarked versions that function on built custom specifications.
As part of autotransformers, various use a common winding which produces no interference or disturbance isolation between the source voltage and the load. Hence, it adjusts the voltage to the load smoothly from zero to the rated supply voltage.
As a general rule, various are designed to be used only in low-voltage applications. Meaning, it is not suitable for high-voltage applications.
Why is it called “Variac”? Who coined it first?
Surprisingly, Variac is a trademark legally owned by Instrument Service & Equipment, Inc. published last 2005. As a brief background, the company offers variable transformers – both in single-phase and three-phase transformers for connection to electric heaters, ovens, lamps, motors, rectifiers. Thus, due to its electronic innovation, Variacs became influential in working more than a trademarked device.
What are the general purposes of Variacs?
Variac transformers have helped commercial establishments and manufacturing industries. Even in your households, variac transformers regulate the voltage power of your electronic devices such as your radio, heater, lighting, etc.
Hence, Circuit Specialists lists some of the best benefits of using variac transformers.
(1) Dimming Incandescent Lighting
Variac transformers are useful to speed up and slow down electric motors, which make lights to glow brighter or to cast dimmer. Nowadays, cinematographers and other film professionals invested in variac transformers to maximize their craft using varying lights.
(2) Roasting coffee beans or nuts
Variac transformers help coffee connoisseurs to achieve the freshest coffee through the device power handling capacities. The problem starts when some coffee beans reject or won’t skin through the heat. As such, by using 6-8amp of variac, coffee beans will take heat and sink.
(3) Powering up an Old Radio or Amplifier
Old radios and amplifiers are vulnerable to dead electrolytes – causing coils to burn out and tubes to fail. Most technicians suggest that variac transformers will reduce the voltage power and bring up the voltage applied over 24 or 48 hours. Also, it enables the capacitors of old amplifiers and other parts to be brought back up gradually for full operation, without damaging parts that have never been used.
(4) Adjusting resistance-type heating devices
Variac auto transformers are regulating tools for resistance-type heating devices. It controls the amount of electricity flowing to an appliance. Nowadays, organic chemistry labs use variacs to control heating mantles. Without variac transformers, heating mantles would cause hazardous effects. Thus, variac transformers provide the safety inside the lab.
(5) Hot-wire cutting of Styrofoams
Regulated heat temperature is a requirement for cutting styrofoams. Hotwires are vulnerable for pressing too much heat, affecting the standard and shape of styrofoams. That’s why using variac transformers adjust the temperature of the hot wire to achieve the optimal value required for cutting.
(6) Testing a repaired electronic device
More often, electronic devices would manifest multiple part failures after a set of electronic testings. Repaired electronic devices are prone to overheating, voltage loss, or worst, its permanent disability. Therefore to avoid burning up of replaced parts, variac transformers slowly power up the repaired unit, preventing damage to replaced parts.
(7) Compensating for line voltage drop power in AC power applications.
Voltage loss occurs when an electric current moves through a cable and grows increasingly weaker, causing an electronic device to appear dimmer and overheat. Line voltage drop power leads to serious electronic complications. As an immediate resolution, using variac transformers will compensate for the voltage loss by reducing voltages.
(8) Changing fan speed over a narrow range.
Variac-style Fan Speed Controllers consist of large, adjustable, and electronic transformers in a box with a control in the front. They reduce the constantly-fed main voltages to the fan. Since variac-style fan speed controllers don’t have automatic temperature control, you need to adjust manually using the controls.
(9) High-current unregulated DC power supply
As the name implies, the output voltage of an unregulated DC power supply is not regulated. Its output voltage doesn’t produce a clean voltage like regulated power supplies do, as small adjustments would cause electrical noise. That’s why variac transformers help in regulating output voltage together with high current rectifier and filter capacitors.
(10) Adjusting the voltage of an AC Power Supply
Lastly, variac transformers primarily operate with AC power supplies. They help in adjusting the voltage of Alternating Current source of open and enclosed construction, with or without metering automatic voltage regulators.
Key Takeaways
Variacs are efficient, sturdy, and easy-to-use tools. In 2005, it was first known as a trademarked electronic device by Instrument Service & Equipment, Inc. However, due to its influential innovation, many electrical companies have produced and replicated the functionality of variac transformers.
Variac transformers generally produce and transform the differing amount of voltage from the same input voltage, wasting only minor core and copper losses. But, what the heck is a variac?
Indeed, most people have often overlooked the importance of variac transformers. In our everyday lives, variac transformers take part to the functionality of our electronic devices, such as:
- Dimming Incandescent lighting;
- Roasting coffee beans or nuts;
- Powering up an old radio or amplifier;
- Adjusting the temperature of resistance-type heaters;
- Hot-wire cutting of Styrofoams;
- Testing a repaired electronic device;
- Compensating for line voltage drop power in AC power applications;
- Changing fan speed over a narrow range;
- High-current unregulated DC power supply; and
- Adjusting the voltage of an AC power supply.
