2020-5-18 · Also read: 7 steps to proper maintenance of diesel generator. Cummins. Cummins is a world leader in the design and manufacture of engines and power generation equipment. It provides generator sets with 15KVA and 500KVA power potential. They offer single-source warranty, planned maintenance, and constant emergency service 24 hours a day, seven days a week as well as back-up power rental .