Protecting Drives and Starters in motors and controllers in high capacity systems requires circuit protection with high melting points and fast fault clearance. Correctly sizing power fuses with melting points and fuse clearance ratings increases circuit protection performance to minimize hardware damage.  This article will explain features of MCLS and BCLS Bolt-In fuses for drives and starters and why these Eaton fuses are used over other types of fuses.

[pullquote align=”full” cite=”” link=”” color=”” class=”” size=””]Eaton MCLS, BCLS Bolt-in R-Rated Fuses for Medium Voltage Drives and Starters[/pullquote]

Let’s first discuss fuse melting points and clearing faults of MCLS and BCLS Bolt-In R-Rated fuses. Overheating of drives and starters causes melting within R-Rated medium voltage fuses to interrupt the circuit and protect electrical equipment from overheating.  Fuse fault clearance is the opening time of a current limiting fuse from the occurrence of an overcurrent until the fuse stops current flow. Eaton R-Rated fuse melting time is 15-35 seconds. These terms apply to all R-Rated fuses and other fuse types for power distribution fuse protection.
 

Why and How to Use Bolt-In Fuses and Hardware

 
Eaton MCLS and Eaton BCLS R-Rated Current Limiting Bolt-In Fuses interrupt
overcurrents to impose an upper limit on the current delivered to a load, protecting drives and starters from damage due to short circuits and other problems in the load. Now that we’ve covered three features used in describing R-Rated fuses: fuse melting point, fault clearance and current limiting – we’ll discuss bolt-on, sometimes called bolt-in fuses.
Bolt-on fuse dimensions and sizing 2.4kV – 7.2kV allow easy installation. They are backup fuses used in high-capacity systems to protect drives and starters from overheating and damage.

Mounting for MCLS and BCLS R-Rated fuses in electrical equipment is easy, as they bolt directly onto the busbar without need of live parts or clips. Eaton current limiting, R-Rated fuses are also available in ferrule mount and clip-on style. See Eaton Fuse Holders and Hardware. Learn more about Eaton Current Limiting Fuses.

Eaton Bolt-In Fuse Features

• Minimum/maximum fuse interrupting ratings, melting time 15 to 35 seconds at a value of 100 times “R” number
• Physical dimensions allow easy installation in hardware
• Available in Limitamp (MCLS) & AMPGARD (BCLS) Bolt-On mounting styles
• 8kV Limitamp Bolt-On constructions available in ratings from 2R to 24R

It’s important to check the data sheets, label, or manual of the power electronic device to understand the short-circuit protection options. With the proper fuse selection, a safer installation can achieve better power electronic device protection. This can result in more
productive operation and higher short-circuit current ratings. Selecting the right size and type of fuse for protecting drives can be simplified with two important considerations:

1. The fuse must be able to withstand the starting current and duty cycle of the circuit without melting.

2. The device must be able to clear a fault quickly enough to minimize damage to the drive or soft starter.

Monster Electrical is a “knowledge-based” independent distributor of fuse, fuse hardware and control equipment. We don’t just ship boxes. Our product and application knowledge goes into every transaction.

Monster Fuses clients can access more than 14,000 power fuse solutions provided from a stock of 100,000+ fuses to eliminate long factory lead times and supply real time solutions for urgent fuse challenges in utility, industrial, institutional and commercial applications.
Call 888-444-4335 West or 877-444-1798 East for help selecting fuses, fuse hardware, power equipment and electrical replacement parts.

Monster Controls: Looking for motor starters, contactors, isolation switches, and replacement parts? Call 888-820-4335.