Yes, the motor getting warm is perfectly normal.
All rotary motors will warm up with use and load, and because the motor on the Eclipse is exposed and not encased in a body/frame like most other tattoo machines, you’re likely to notice it heat up more than you would any other machine.
A couple things that cause the Eclipse to heat up more are using the machine with cartridges without removing the return spring, and/or not using a foot pedal. Even so, the machine will still work fine.
If you are using the Eclipse with cartridges, we recommend removing the return spring as it will improve its performance. The membrane in the cartridge does the job of the return spring.