A generator can be expensed since it is a separate unit if the cost is $2,500 (safe harbor amount) or less. However, you may choose to capitalize it so you can spread the deduction over future years to net against future income.
Another option, if over the $2,500, is to claim a Section 179 deduction. This link explains which types of assets can and
cannot qualify for Section 179 expense deduction IRS Section 179 Property
Qualification and Limits . Section
179 is also limited to the taxable income derived from the business activity