ABB SACE Megamax F air circuit breaker Low Voltage

The SACE Megamax F was a flagship, fixed-mounted air circuit breaker known for its extremely high breaking capacity, robustness, and reliability. It was designed to protect electrical installations in large industrial plants, infrastructure projects, and critical power distribution systems.

Key Features and Characteristics

Extremely High Breaking Capacity:

This was its standout feature. The Megamax F offered breaking capacities up to 150 kA (at 415V AC), making it suitable for locations with very high potential fault currents, such as close to a power plant or a large utility substation.

Fixed Version (The "F"):

The "F" in Megamax F stands for "Fixed." This means the breaker is bolted directly and permanently onto the busbars within the switchboard or distribution board. It does not have a draw-out mechanism.

Advantage: More compact and cost-effective than a draw-out version.

Disadvantage: Maintenance or replacement requires de-energizing and physically accessing the entire panel.

High Continuous Current Ratings:

It was available in a wide range of frame sizes, with continuous current ratings (Iu) typically from 800 A up to 6300 A.

Advanced Trip Units (Releases):

The Megamax F was equipped with sophisticated electronic trip units like the PR111/LSI or the more advanced PR113/DPI.

These units provided comprehensive protection features:

L - Long-time delay (for overload protection)

S - Short-time delay (for selective tripping with downstream breakers)

I - Instantaneous (for high-level short circuits)

G - Ground-fault protection (on specific models)

The PR113/DPI featured a digital display for current measurement, load monitoring, and event logging.

Robust Construction:

Built to withstand the harsh electrical and mechanical stresses of industrial environments. Its design ensured high durability and a long electrical service life.

Model Structure Analysis

A complete Megamax F model number typically consists of several sections, roughly formatted as follows:

SACE Megamax F [Frame Current] [Number of Poles] [Release Type] [Breaking Capacity] [Operation Method] [Special Code]

List of Key Model Parameters

1. Frame Size

This is the heart of the model number and refers to the maximum current rating the circuit breaker can support. Common frame sizes include:

F1 - 800 A

F2 - 1250 A

F3 - 1600 A

F4 - 2000 A

F5 - 2500 A

F6 - 3200 A

F7 - 4000 A

F8 - 5000 A

F9 - 6300 A

2. Number of Poles

3 - Three-Pole

4 - Four-Pole

3. Release Type

This is the "brain" of the circuit breaker and is clearly indicated in the model number.

PR111 - Basic electronic trip unit, providing LSI protection (long delay, short delay, instantaneous).

/P indicates standard configuration.

Suffixes such as /L may indicate different feature combinations.

PR113 - More advanced electronic trip unit, with a digital display (DPI) that displays current, voltage, power, and other parameters, and offers a wider range of protection functions and diagnostic capabilities.

4. Breaking Capacity

N - Standard Breaking Capacity

H - High Breaking Capacity

L - Very High Breaking Capacity (up to 150kA)

5. Operation

F - Fixed

(Megamax also has an "M" designation for withdrawable, but since you specified F, the F designation is primarily used here.)

6. Special Versions and Accessories

/B - Basic Version

/M - With Manual Charge Mechanism

Other codes are used to designate accessories such as auxiliary contacts, undervoltage release, locking device, and interlocking mechanism.

Comprehensive Model Example

Based on the above rules, some typical complete Megamax F model numbers might look like this:

SACE Megamax F2 3 PR111/B N F

Meaning: Megamax F, 1250A frame, three-pole, PR111 basic release, standard breaking capacity, fixed.

SACE Megamax F4 4 PR113/D L F

Meaning: Megamax F, 2000A frame, four-pole, PR113 trip unit with display, very high breaking capacity, fixed-mount.

SACE Megamax F6 3 PR111/P N F M

Meaning: Megamax F, 3200A frame, three-pole, PR111 trip unit, standard breaking capacity, fixed-mount, with manual stored-energy mechanism.

Ultimate Notice

Discontinuation and Replacement: As mentioned above, the Megamax F has been completely discontinued. Its direct and official replacement is the ABB SACE Emax 2 series.

Emax 2 Comparable Models: If you are looking for a replacement part or selecting a model for a new project, you should consider the Emax 2. Its fixed-mount model is typically E2F.

For example, Megamax F2 (1250A) corresponds to Emax E2.1F.

Megamax F4 (2000A) corresponds to Emax E2.2F.

Megamax F6 (3200A) corresponds to Emax E2.3F.