DC Fuses Blowing

Yes. Consult an appropriately-qualified local electrician. That individual will have a closer view of the installation and will be able to apply such test equipment as is necessary to form a fair assessment of it and make appropriate recommendations.

After all, the installation cannot be seen from here.

buy big fuses

DC Semiconductor fuses are special, and faster-acting than normal fuses. It is critical that fuse-selection for this application is done by an expert. Most good fuse companies make such fuses, generally called High-speed semiconductor fuses. Since they have to act very quickly, unless they are correctly chosen, nuisance trip or underprotection will result.

i suggest you ask the fuse manufacturer to recommend the right fuses.

Here is one link :BUSSMANN

you may need to change the rating of the fuse itself. The fuse rating should exceed the amperage demands of the appliances it protects, so you may have to buy bigger fuses to avoid problems

If one associates cost with complexity and technology, and thinks that a fuse is not a technical product, i would recommend downloading and reading this document Bussmann Fuse Training Book

If you use a bigger fuse because the present one is blowing, you are probably losing protection to the drive components. This is not a child's play. It is a serious, professional job of selecting the proper protector for the part to be protected. Otherwise you can as well eliminate the fuses altogether.

Without getting too technical, there are occasions, depending on the type of inverter, and the motor it is driving, where, if the drive power is reduced, (say, to allow the motor to slow down), or the DC bus voltage drops, the motor can become a generator for a short space of time, back feeding the DC bus, leading to excess voltages and currents on the DC bus. This is possibly the cause of your problem. I am not an electrical engineer, but have seen big wire wound load resistors, filter networks, and fancy control gear to reduce this excess generated voltage. You need to talk to the manufacturers of the inverters, or an AC drive consultant for a solution to this problem.