T HREE-SHOT TYPE MZR F USE CUTOUT

Transcription

1 T HREE-SHOT TYPE MZR F USE CUTOUT Page 1 of 7

2 D ESCRIPTION It is known that about 90% of the defects that occur in an air distribution system, are of a transient origin, i.e., are transient faults which may last a few cycles to a few seconds, usually caused by: lightning, bird or small animals, tree branches... These defects cause blown fuses causing disruptions that can last minutes to even hours, compromising the quality of service and customer satisfaction. Seeking greater continuity in the supply, and minimize the operational costs resulting from displacements of electricians for locations which are distant most of the times to replace blown fuses, MAURIZIO offers Three-Shot Type MZR Fuse Cutout. The Three-Shot Type MZR Fuse Cutout is basically composed of three type "C" bases, equipped with cartridges and fuses, installed next to each other in the same structure and mechanically and electrically interconnected. The source is connected to the top of the switch and an electrolytic copper link interconnects the bases. The load is connected in the lower part of the Cutout. (See illustration). O PERATION In fault conditions in the circuit, the first fuse is broken, causing a move of 160 downwards. At the end of the route the cartridge triggers the movable contact device, which automatically reconnects the circuit thru the second cartridge. The reconnection time is of the order of 500ms. This is repeated when the next fuse is disrupted, promoting another reconnection to the circuit. The final circuit interruption will only happen after the third fuse burns. At this time the presence of an electrician will be required to replace the blown fuses and manually reconnect the circuit. This operation sequence is characteristic of the Three-Shot Fuse Cutout. Page 2 of 7

3 A PPLICATION In general the protection of air distribution circuits is made through phase and neutral relays installed at the substation and a large number of fuse Cutouts installed in extensions and / or derivations along the circuit. (See illustration) Thus, the protection is dimensioned to operate when in fault conditions selectively, i.e. it will interrupt the circuit through the operation of the nearest fault protection equipment. Thus, transient or permanent defects, downstream of any fuse will result in disruption to customers that can last a few minutes to up to a few hours, as it always depends on the electrician s action to replace the fuse and reconnect the disconnected section. The application of the Three-Shot Type MZR Fuse Cutout in extensions and / or derivations of the air distribution system offers, besides protection as other Fuse Cutouts, a greater continuity of supply, quality and reliability which is demanded by the distribution system. Statistics reveal that 90% of the defects in the distribution system are transient in nature, and of these, 90% are eliminated with a sequence of opening and reconnecting of the protection device. With this, in addition to the quality and continuity of supply to customers, the Three-Shot Type MZR Fuse Cutout provides the user with other benefits such as: Reduc on of up to 60% in the number displacement for service and restora on of the system. Reduc on in opera onal costs. No ceable reduc on in the number of complaints from customers. Reduc on of 60% in prolonged interrup ons. Page 3 of 7

4 S PECIFICATIONS kv Amperes, RMS Leakage Distance Dimensions Nom. Max BIL Cont. Interruption (60Hz) Sym. Asym. Inches (mm) A B C D E F G H Inches (mm) 13,8 thru (240) 19.7 (500) (412) (330) (163) 20.4 (519) 3.8 (96) 8 (203) 20 (510) 24,2 thru (320) 22.3 (568) (425) (380) (205) 25.2 (640) 3 (77) 8 (203) 20 (510) 34,5** thru 38** (432) 22.3 (568) (425) (380) (205) 25.2 (640) 3 (77) 8 (203) 20 (510) ** Applicable for protection of single-phase-to-neutral circuits (lines or transformers) only, and grounded-wye connected capacitor banks in solidly grounded-neutral (multigrounded-neutral) systems. Page 4 of 7

5 C HARACTERISTICS 1- Parallel connector Made of tinned bronze for cables from 8 AWG to 4/0 ACSR. To ease the connection, it can accommodates two conductors with different size in a single connector. Also available in other models. 2 Upper Contact - Silver to silver; stainless steel springs offers high contact pressure. 3 Attachment Hooks - Used as tool support for energized opening as well as to guide the fuse tube during closing. 4- Fuse Tube - Vulcanized fiber covered with fiberglass and painted with a special UV resistant epoxy. 5 Lower Contacts Silver to silver; non ferrous springs offer high contact pressure 6 Flipper Stainless steel construction; in conjunction with the toggle joint allows, especially during closing, the fuse link to be subject to traction forces of over 3 Kgf; it also allows for high speed fuse link separation. 7- Trunnion - Silver plated high strength cast bronze construction; it assists the fuse tube alignment during closing. 8- Insulator - High strength porcelain in accordance with ANSI, IEC. 9- Contact of Mobile Transfer - In silver electrolytic copper 10- Contact of Fixed Transfer - In silver electrolytic copper, kept under high pressure by a spring of phosphor bronze. 11 Protector Disk - high density polyethylene. Page 5 of 7

6 S TYLES Rated Voltage Thru 15 kv BIL 110 kv Leakage Distance 9.4 (240mm) Nominal Current 100 A Net Weight (lbs) Pallet Quantity 12 Rated Voltage Thru 27 kv BIL 125 kv Leakage Distance 12.6 (320mm) Nominal Current 100 A Net Weight (lbs) Pallet Quantity 12 Page 6 of 7

7 Rated Voltage Thru 38 kv BIL 150 kv Leakage Distance 17 (432mm) Nominal Current 100 A Net Weight (lbs) Pallet Quantity 12 MAURIZIO & CIA. LTDA. Av. Dr. Abilío Sampaio, Vila Gustavo São Paulo - SP - Brasil Tel.: Fax.: maurizio@maurizio.com.br Page 7 of 7