Theory Of Operation - Respironics REMstar Choice Service Manual

Specifications and Wiring Diagram

1.2 Theory of Operation

The REMstar Product family is constructed of four major component assemblies: the Motor Blower Assembly,
the Printed Circuit Board Assembly, the Transformer Power Supply, and the Enclosure Housing. The CPAP
pressure and flow is generated by the motor blower assembly. This assembly generates air flow via a back-
ward vein impeller spinning in excess of 7000 RPM. The Printed Circuit Board supplies the voltage required
to power the motor and impeller. The Printed Circuit Board uses analog circuitry to rectify the voltage from
the transformer and supply it to the motor at a level correlated to the required CPAP pressure level. The
Transformer receives the AC voltage from a connection to a electrical wall outlet and steps the voltage down
to approximately 12 volts* DC for use by the printed circuit board. The Enclosure Housing insulates the
electrical components of the unit from the user.
*NOTE: The Transformer in the original REMstar steps the voltage down to approximately 18 volts DC. The
Transformer in the Choice unit steps the voltage down to approximately 12 volts DC.
REMstar Service Manual 1-5