Your 5kw converts to 6.7 hp, so a single "V" belt should work. I think
the rule is 10hp per "V" belt. As others have pointed out a belt needs
no lube, where any chain drive will need it. Have you looked at the PTO
gear drives available to mate generators to tractor PTOs?

Paul

Laurie Forbes wrote:
I plan on buying a "Voltage Master" 5 KW generator (3600 RPM) that I will
power from my tractor front PTO. I would like to run the tractor at about
1600 RPM so will have to "gear up" by about 2.25/1. Question is, should I
use a V belt or roller chain?? I suppose either would work but each has
advantages and I wonder what would be best overall.

BTW, the no-name 6 KW diesel gen sets at the auction I was looking at went
for $1,200 so I passed.

TIA for any suggestions.

Laurie Forbes