Power Fuses; Vacuum Contactor - Toshiba JK 720 Instruction Manual

Basic Installation and Operation Guide

Power Fuses

The power fuses supplied in Toshiba JK 720 ampere controllers
are of the bolt-in or clamp-in type, therefore overheating due to
loss of fuse clip pressure is not a problem. The tightness of the
fuse clamping bolts (Fig. 44) should, however, be periodically
checked and maintained within a range of 20-30 ft-lbs.
Check the power fuses for any signs of discoloration. A fuse
barrel which appears darker than others indicates overheating.
Possible causes of fuse overheating, other than load problems,
are misapplication (fuse current rating too small), loose fuse
connections, or a damaged fuse.
Check the fuse barriers for cleanliness and proper positioning, as
shown in Fig. 45. There are three vertical barriers, two located
between adjacent fuses and a third between the right hand fuse
and the operator mechanism. A fourth angle-shaped barrier is
positioned in front of the isolation switch (Fig. 46).

Vacuum Contactor

Maintenance instructions for the HCV-6KAU vacuum contactor
are provided in a separate publication, number VF010H08A.
Contact the equipment supplier or the factory if this publication
is needed and was not provided with the equipment.
Radiation Exposure Hazard. X-Radiation
may cause illness or injury. Stay at least
CAUTION
1 meter (3.3 feet) away from the contactor
during high-potential tests.
Fig. 46 Angled Barrier In
Front Of The Isolation Switch
TOSHIBA
JK Series 720 Controllers
Fig. 44 Checking Power Fuse Clamping
Bolt Torque
Fig. 45 Fuse Barrier Placement
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