A PSI blower chip loading system plugged up and tripped the breaker. A maintenance employee locked out the machine, cleared the plug, and restarted the machine. The employee was checking for air flow through the pipes with his right index finger hanging at the stop plate when the mechanical sleeve lacerated the finger pad. The machine amputated a chunk of the right index finger pad. The fingernail and part of the bone were removed to close the skin around the end of the finger.