Teco L510-203-H1-U fuse

93xs2003

Registered
Registered
Joined
Mar 3, 2021
Messages
17
The Teco L510 manual calls for a fast acting 50Amp 690VAC fuse for the 3HP single phase input application (refers to a Bussman 50FE 'brittish style' fuse with bolt lugs).
The spec'ed 50FE is not generally stocked at digikey, newark, mouser etc.. I'm wondering what folks are using for 3HP Teco applications.

Searching around, other TECO manuals have shown two fuse requirement tables: one spec'ing 30A/300VAC fuses for general application (Non UL), and the Bussman 50FE fuse for UL rated applications. . . So, I assume they needed a fast acting fuse to address the UL requirements regarding a dead short on the motor side, and that this 50A monster was what was required to avoid fireworks during the test.

Does anyone have a reasonable cost alternative to the spec'ed fuse for the L510-203?
 
You can get buy with a 30A fuse and/or breaker. I have had no issues running a wide range of 3 Hp VFDs and never had one blow a fuse under load. I would suggest if you are adding fuses to go with a CC type holder with a Bussman CC cartridge fuse, either a low-peak or fast blow. You can find these on eBay fro reasonable prices. Also note that fuse holders come in different suize ranges, if you needed something more than 30A then would probably use a J class fuse. In addition there are difference between the different styles of fuses at the same amperage/type.
Allen Bradley 1492-FB2C30-L CC style 30A max fuse holder:

CC 30A fuses, look for either one, I tend to use fast blow, but low peak will give you a bit more headroom:
Bussmann FAST BLOW KTK-R-30 Class CC
Bussmann LOW PEAK LP-CC-30 Class CC

Breakers protect the wire, so if you are running it off of a 30A panel breaker on a dedicated line, probably all you need. If it is part of a shared or higher current line, then could fuse locally or on can use UL 489 breaker.
 
Yes my VFD also specified a fast-blow 50A fuse, so I used one that fit my fuse-disconnect box. I doubt the variance among fast-blow fuses is too important.
 
You can get “z-curve” breakers, which are supposed to be fast-trip, similar to fast blow fuses. I’ve seen as the type of breaker meant to be an aux breaker used in a device like your motor control box. I believe that’s what UL-489 means? Circuit panel breakers need to meet different requirements.
 
Fuse ratings have changed mightly since OSHA came along. In the late 60s and early 70s, cartridge fuse sizes indicated voltage and current ratings. I still have a 250 Amp 300 Volt replacable cartridge on my pouch for carrying miscellaneous parts like screws and such. I can't see why you would need a fuse above 600 volt rating for a device running on 240 Volts. There is a higher rating internally where the rectifier peaks, but on 240 Volts, it shouldn't reach much beyond 300 Volts. I would venture to guess that a "semi-conductor rated" fuse of 300 Volts should suffice. I can see where the line is 575 Volts one would need a high voltage device. But that voltage is used in Europe and ?. In the States 480(600 V) is the norm for industrial installations, with 240(300 V) being used for residential. Perhaps the design is used "as is" to be universal. . .

There are circuit breakers rated for semi-conductor use. But the fuses are available widely and a bunch cheaper. And probably much easier to adapt. A 300 Volt fuse is smaller (length) than a 600 Volt device so probably a matter of drilling another hole is worst case. There are(or were) adapters for using the smaller cartridge sizes in a high voltage fuse holder as well.

.
 
Thanks. This was helpful.

Pure speculation, but I don't think they actually need the 690V capability, rather they are specifying that the 50A 690V component is what 'worked' to successfully pass their UL compliance testing. It's likely the 200,000A interrupt capability that comes along with this fuse was what they needed in order to avoid fire / sustained arc / exploding components / etc. when placed in a dead short condition and provided a supply w/ a slow 30A breaker and an essentially unlimited current source behind it.

The CC fuses Mark references have 200kA interrupt rating. I'll start with the FAST and see if 30A provides enough headroom for over-current loads. I can't imagine a mill is going to pull 240% overcurrent on startup (w/ an acceleration ramp) or in normal use.
 
Back
Top