The Clay Adams SeroFuge 2002 has a high and low speed setting, 3100-3550 for high and 2350-2450 for low. High speed is achieved by direct line voltage, specifically 115VAC. Higher or lower voltages will affect the high speed.
The low speed is achieved by phase control of the line voltage through the control pcb, and moderated via hall effect switch integral to the motor. The feedback of this switch enables the pcb to adjust the drive voltage.
I would first verify the speeds you are getting with a photo tach. If you are not achieving the specified speeds for high or low, you may be having a motor or pcb issue. If your speeds are within OEM specification, further troubleshooting will be needed. Feel free to give us a call for more assistance.
David M - Ozark Biomedical