Otter Tail Power - Douglas, ND
An interesting transformer bank with two possibly 'homemade' fused cutouts on opposite ends of the middle crossarm.
The left one is an early style (likely late 1920s vintage based on the insulators on the bracket) and seems to be adapted to accept a 'spring link' style fuse. The one on the right is an unusual porcelain style that has likewise been adapted to use a 'spring link' style fuse.
Fused cutouts are high-voltage fuses adapted for use on power lines and are commonly used to protect transformers or branch lines. At this voltage level, it is important to separate the ends of the blown fuse before an arc forms across the gap (and which results in equipment damage if not addressed quickly). Spring-link cutouts like these keep the fuse link under tension, immediately pulling the ends apart when the fuse blows. They are also arranged so a lineman can replace the fuse from a distance by using an insulated pole.
Modern cutouts use a 'dropout' mechanism where the link is enclosed in a rigid tube, but part of the assembly is still spring-loaded. When the fuse blows, an arc briefly forms and causes one end of the blown fuse to be ejected from the tube (this is the loud BANG many people hear when one lets go). Once the fuse separates, the spring relaxes, causing the tube to swing downward and showing the lineman that the fuse needs replacement. The tube can then be retrieved, a new fuse link fitted, then reinstalled in the cutout to restore power.
Otter Tail Power - Douglas, ND
An interesting transformer bank with two possibly 'homemade' fused cutouts on opposite ends of the middle crossarm.
The left one is an early style (likely late 1920s vintage based on the insulators on the bracket) and seems to be adapted to accept a 'spring link' style fuse. The one on the right is an unusual porcelain style that has likewise been adapted to use a 'spring link' style fuse.
Fused cutouts are high-voltage fuses adapted for use on power lines and are commonly used to protect transformers or branch lines. At this voltage level, it is important to separate the ends of the blown fuse before an arc forms across the gap (and which results in equipment damage if not addressed quickly). Spring-link cutouts like these keep the fuse link under tension, immediately pulling the ends apart when the fuse blows. They are also arranged so a lineman can replace the fuse from a distance by using an insulated pole.
Modern cutouts use a 'dropout' mechanism where the link is enclosed in a rigid tube, but part of the assembly is still spring-loaded. When the fuse blows, an arc briefly forms and causes one end of the blown fuse to be ejected from the tube (this is the loud BANG many people hear when one lets go). Once the fuse separates, the spring relaxes, causing the tube to swing downward and showing the lineman that the fuse needs replacement. The tube can then be retrieved, a new fuse link fitted, then reinstalled in the cutout to restore power.