Qualitrol STB-200-4 Main Tank Smart Transformer Breather


The transformer bladder, oil, and insulation system can degrade over time due to excess moisture in the atmosphere. This degradation may result in aging of the asset or reducing the overall life and performance. With multiple communication options, Qualitrol’s Smart Breather can provide a wide range of monitoring solutions for any application.


  • Reduce maintenance costs with learned transformer breathing patterns and self-regenerating desiccant
  • Color changing silica gel desiccant allows for a visual confirmation of breather regeneration
  • Multiple communication options including 4-20 mA, RS-485 MODBUS and local USB port provide for a variety of monitoring solutions for any application
  • Front mounted indication LED lights of green, amber, and red indicate breather status and alarm capabilities
  • Oil desiccant size of 136,000 liters/36,000 gallons


  • Polar models offer additional internal heaters to withstand harsh temperatures down to -60 °C
  • Offshore Xtreme™ models contain material sets specially engineered to adapt to life in harsh marine environments
  • Multiple mounting options available for new or retrofit installation
  • Includes a solenoid valve that closes during the regeneration process to ensure moisture is not wicked into the transformer accidentally

Group Created with Sketch. Applications

The Qualitrol STB series smart transformer breather removes moisture from air entering oil-filled transformers or LTC conservators. The breather is automated to regenerate the silica gel desiccant at a user selectable time interval or relative humidity (RH) threshold. Alarming capability and communications reduce unnecessary breather maintenance costs over time. The silica gel may be regenerated many times without replacement due to internal heaters inside the unit that drive off accumulated water on a transformer exhale cycle. Recommended for use on Medium/Large Transformers with a voltage range of 138 kV-345+ kV.

Compare to Similar Products


Traditional Breather in the Marketplace

Utilizes silica gel to dry atmospheric air as the transformer breathes

Low initial cost of ownership but associated maintenance costs outweigh this over time

No alarming capability or failure detection available, must rely on human interaction maintain and service the breather

Desiccant disposal costs may apply if silica gel containing cobalt is used

Learn More

Other Smart Breathers in the Marketplace

Do not utilize color changing desiccants (Color changing silica gels allow the user to have a secondary visual indication of regeneration)

Some do not utilize a pressure sensor and solenoid valve technology to detect breathing shifts in the transformer (This prevents liquid water from being drawn into the transformer accidentally)

Some others do not have options for harsh environmental conditions such as Polar or Offshore Xtreme™ models

Learn More

Qualitrol STB-200-4 Main Tank Smart Transformer Breather

No need for unnecessary maintenance or replacing silica gel in the field

Alarming and failure detection capability; there is no need to rely on human interaction

Utilizes a color changing silica gel as a secondary indication that regeneration took place giving peace of mind

Utilize a pressure sensor and solenoid to detect inhale and exhale phases of the transformer and to prevent excess moisture from being drawn into the transformer

Learn More
You Also Might Be Interested In
This Product Works Well WIth