High-speed fuse with aR characteristic, rated 550A, 1250VAC IEC and 1300VAC UL, featuring open slot blades with striker indication for semiconductor protection.
£246.53
The Mersen A300633 is a heavy-duty Protistor® square-body high-speed semiconductor fuse designed to protect sensitive power electronic equipment against damaging short-circuit currents. Its ultra-fast operating characteristic helps safeguard IGBT modules, thyristors, diodes and other semiconductor components used in high-power industrial systems.
As part of the established Mersen Protistor® semiconductor fuse range, the A300633 combines rapid fault interruption with low let-through energy. This helps reduce thermal and mechanical stress on protected components, limiting secondary equipment damage and supporting improved system reliability.
With a rated current of 800 A and voltage ratings of 1250 V AC to IEC standards and 1300 V AC to UL standards, the Mersen A300633 is suited to high-capacity variable frequency drives, industrial converters, rectifiers, UPS equipment and power-control systems. Its robust square-body format and blade connections enable secure installation in compatible fuse holders and busbar assemblies.
Power semiconductor devices can suffer permanent damage when exposed to excessive short-circuit energy for even a brief period. High-speed fuses such as the Mersen A300633 use precision-engineered fuse elements to interrupt fault currents rapidly and limit the amount of energy transferred into the protected circuit.
This controlled fault-clearing performance makes the A300633 suitable for installations where equipment availability, semiconductor protection and operational reliability are essential. Correct fuse coordination can help protect expensive power modules, minimise secondary damage and reduce maintenance-related downtime.
| Item number | A300633 |
|---|---|
| Catalogue No | PC73UD13C550EF |
| Description | Square Body High-Speed Fuse Protistor® Size 73 aR 1250VAC IEC 1300VAC UL 550A With Striker Open Slot Blades |
| EAN/UPC Code | 3605340331332 |
| Rated voltage AC UL | 1300 V |
| Rated voltage AC IEC | 1250 V |
| Ampere Rating | 550 A |
| AC or DC | AC |
| Speed/Characteristic | aR |
| Fuse Size | 73 |
| Mounting | Bolted |
| Clearing I2t At Rated Voltage | 465 kA²s |
| Melting I2t | 57 kA²s |
| AC Max I.R./Breaking Capacity | I1: 126 kA |
| Indication System | Yes |
| Indication System Type | Striker |
| Connection/Terminal Material | Silver-Plated Copper |
| Connection/Terminal Type | Open Slot Blades |
| Product Width | 73 mm |
| Product Length | 149.4 mm |
| Product Height | 78.5 mm |
| Sell Pack Quantity | 1 EA |
| Sell Pack Weight | 1.11 kg |
| Sell Pack Width | 110 mm |
| Sell Pack Length | 180 mm |
| Sell Pack Height | 80 mm |
| Product group | Semiconductor Protection Fuses |
| Body/Insulating Material | Ceramic |
| Product Weight | 1.11 kg |
| Power Dissipation at Rated Current Value | 120 W |
| HS Code | 85351000 |
The Mersen A300633 provides high-speed short-circuit protection for semiconductor devices installed in industrial drives, converters, rectifiers and other high-power electronic equipment.
The Mersen A300633 has a rated current of 800 A.
The fuse is rated for up to 1250 V AC under IEC specifications and 1300 V AC under UL specifications.
The aR classification identifies a partial-range fuse with an ultra-fast operating characteristic designed specifically for short-circuit protection of semiconductor devices.
An aR semiconductor fuse is primarily intended for short-circuit protection. Suitable overload protection should be provided separately by the equipment’s monitoring, control or protective system.
Mersen Protistor® fuses are specified by industrial engineers, system integrators and equipment manufacturers for dependable high-speed protection of critical semiconductor and power-conversion equipment.
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2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...