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GE Medium Voltage Power Fuses by Mersen

Current-Limiting Power Fuses - Medium-voltage distribution systems that supply industrial plants, shopping centers, hospitals, schools, office buildings and underground residential service often require special types of over-current protection. This is of particular importance because, in the event of a fault, these types of systems frequently produce high short-circuit currents that may result in damage to busway, motors, switches and other equipment. Current-limiting power fuses are widely used in these applications because they afford excellent over-current protection and noiseless operation, and because they can be used in confined spaces. The amount of damage in the faulted area and the mechanical stress and strain on busway, switches and other apparatus carrying the fault current is proportional to the square of the current and to the length of time the fault persists. By limiting the let through energy at the fault, properly applied current-limiting fuses assist in limiting or preventing short-circuit damage to busway, circuit breakers, switches, and other electrical components. Current-limiting power fuses are manufactured in ratings ranging from 0.6 kV through 38 kV and in continuous current ratings from 0.5 amperes through 900 amperes. Various designs are available for use with motors, transformers, capacitors, and circuit-protection equipment.

Current-limiting power fuses offer significant advantages for protecting electrical power systems and equipment. Advantages include:

  • High interrupting capacity
  • Noiseless operation, since the interruption is totally contained
  • Fast current-limiting operation when troublesome high available fault currents are encountered
  • No pressure build-up, therefore, no vents or special reinforced compartments are required

Capacitor Fuses (EJO-5, 9F60 Series) - Backup Capacitor current-limiting fuses are designed for individual capacitor protection. The EJO-5 can be used in any location (indoor or outdoor). The major purposes of such fusing are: (a) to protect the systems from failed capacitor units, and (b) to prevent damage to adjacent capacitors and associated equipment.

General Purpose Fuses (EJO-1, 9F62 Series) - General Purpose current-limiting fuses are designed to interrupt the high-fault currents and also the low-fault currents down to approximately 1.6 to 2.2 times their continuous current rating. This fuse is defined in the IEEE Std C37.40 -1993 (3.1.57) as “A fuse capable of interrupting all currents from the rated interrupting current down to the current that causes melting of the fusible element in no less than one hour.” These fuses can be used outdoors without any protecting enclosure and are available from 5.5 to 15.5kV and 20 to 900A.

Power Distribution Fuses (EJ-1 and EJO-1, 9F60 Series, “E” Rated) - Power distribution current-limiting fuses are designed not only to interrupt the high-fault currents, but also to interrupt low-fault currents down to approximately 3 times their continuous rating. The EJO-1 models can be used outdoors without any protecting enclosure.

Potential Transformer (EJ-1, 9F60 Series, “E” Rated) - Current-limiting fuses are designed to interrupt the high-fault currents and also the low-fault currents down to approximately 3 times their continuous current rating and are available from 0.625 to 15kV, from 0.5 to 3 Amps.

Motor Starter Fuses (EJ-2, 9F60 Series, “R” Rated) - Backup motor starter current-limiting power fuses are designed to provide short-circuit protection of individual motors. These fuses are designed to interrupt current from 100 times the R-rating up to 50kA rms symmetrical at rated voltage. The element of these fuses is designed to withstand the cyclic motor-starting application. By definition, a back-up current-limiting fuse is “A fuse capable of interrupting all currents from the rated maximum interrupting current down to the rated minimum interrupting current.” Standard IEEE C.37.40-1993 (3.1.8). Motor Starter Fuses are available from 2.54 to 7.20kV, From 70 to 700A (2 to 50R).

Fuse Supports and Disconnecting Switches (9F61 Series) - Fuse supports, non-disconnecting, are used primarily in potential transformer circuits, or where there is some other disconnecting or isolating device in series with the fuse in the circuit. Fuse supports can be mounted vertically or horizontally. The EKO-1 models are designed to be installed outdoors. Disconnecting switch devices have the additional feature of serving to isolate the equipment they protect. It should be noted that disconnecting switches are not load-breaking devices, therefore, the circuit must be open prior to the fuse disconnection. The EKO-3 models are designed to be installed outdoors. Select either a fuse support or a disconnecting switch for each fuse. Fuse supports and disconnecting switches include live parts for both ends.

The Parts Super Center stocks a wide range of Fuses including General Purpose (EJ-1/EJ-01), Motor Starter Fuses (EJ-2), as well as Fuse Supports and Live Parts. We also have the information your looking for, from Selection and Application guides to Competitive Cross References.

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