Bussmann 170M6621 Eaton series high speed square body fuse, 1300V (UL), 1250V (IEC), 2000A, 200 kAIC, None, Fuse, Blade end X blade end, Class aR

It's a high speed fuse built for semiconductor protection, rated 2000 A with a 200 kAIC interrupting rating. The aR utilization category means it's an accompanied semiconductor fuse: it protects the diodes, SCRs or IGBTs against short circuit only, so it has to work alongside a separate overload protective device. If you need a fuse that also handles overload on its own, an aR part is the wrong choice.

Pre-arcing I2t is 1,150,000 A2s and total clearing I2t is 6,350,000 A2s at 660 V. Compare the clearing figure against the I2t withstand of the diode or thyristor you are protecting: the device rating has to be higher than the fuse's clearing I2t, or the semiconductor lets go before the fuse does.

No, and swapping them causes trouble. Class aR, which is what the 170M6621 is, is a partial-range fuse: short circuit protection only, and it needs a separate overload device such as a thermal overload relay or drive electronics in series. Full-range gR and gS types clear overloads as well. If the existing fuse in the drive stack is marked gR, do not drop an aR in its place without checking that overload protection exists elsewhere in the circuit.

No. The 170M6621 is built without insulated metal gripping lugs (IMGL), so there is no insulated pull handle on the body. Plan on de-energizing and unbolting it with tools rather than pulling it by hand. If your maintenance procedure depends on IMGL-style handling, specify a 170M part that lists IMGL.

Watt loss is 175 W at rating. That is real heat inside the cabinet, so on a multi-fuse assembly the ventilation and any derating for enclosure temperature need to account for it. The fuse also weighs 934 g, which matters for the bracing and torque on the bolted tags.

It carries UL Recognized component status and is CE Marked, which covers both a UL-scheme panel build and IEC/CE machinery exported to Europe. Note that UL Recognized is a component listing, so the acceptance rests on the assembly it is installed in meeting its own listing conditions.

Order it as Bussmann 170M6621, the genuine Eaton part number. The 170M family runs a long sequence of numbers where a single digit change moves you to a different body size or ampere rating, so quote the full six-character number rather than just "2000 A square body" when you reorder.