MFO-RTC-Srs-Transformers

Supported Applications

The Omega MFO/RTC series comprises AC Current Transformers designed to reduce line current to a secondary value of 5A or 1A for measurement and protection applications. These transformers are specified for use with ammeters, wattmeters, instrumentation, relays, and energy management systems.

Operating Conditions & Performance

The series operates within an ambient temperature range of -25 to +50°C (per family manual) and supports storage temperatures from -40 to +80°C. Humidity ratings are specified as 90% without condensing, with an enclosure rating of IP30 per CEI/EN 60529. Performance is defined by a class 1 accuracy at a secondary current of 5A and power of 40 VA (per series data sheet note). The measurement range spans from 20:5 to 3000:5 current ratios, with standard output signals available as 5A or 1A secondary currents.

Configuration Options

The MFO/RTC series is offered in two primary form factors: solid-core (MFO) and split-core (RCT). Selection parameters include window size, current ratio, burden capacity, and terminal configuration options.

• Solid-Core Models (MFO): Available with window sizes of 30.5 mm, 41.5 mm, 60.3 mm, and 100 mm.
• Split-Core Models (RCT): Offered in RCT-15 series variants with window sizes ranging from 35 mm to 110 mm for installation around existing conductors without disconnecting power.
• Burden Ratings: Configurable burden values include 2 VA, 2.5 VA, 3 VA, 5 VA, 7.5 VA, 10 VA, and 15 VA depending on the model number.
• Housing & Connections: The series features an ABS self-extinguishing case. Options include TAB/TAP series with sealing terminal covers and DIN rail fixing; TAF series with protected faston caps and DIN rail fixing; MFO series with protected terminals; and RCT series with insulated wire outputs.
• Cable Voltage Drop: Technical data provides voltage drop calculations for cable sections of 1.5 mm², 2.5 mm², 4 mm², 6 mm², and 10 mm² at various lengths (up to 10m or 100m) for both 5A and 1A secondary configurations.

Key Product Differences

The series distinguishes between the MFO solid-core family, which requires conductor insertion during installation, and the RCT split-core family designed for retrofit applications. Model numbers encode specific performance parameters; for example, RCT1538005A denotes an 800/5 A current ratio with a 91 mm window size and 15 VA burden, while MFO10010005A indicates a solid-core unit with a 1000/5 A ratio, 100 mm window, and 10 VA burden. All units carry CE marking and are manufactured in China under ISO 9001 certified facilities (Stamford, CT; Manchester, UK).