Edwards / Seiko Seiki SCU-21D Turbo Molecular Pump Controller

The Edwards / Seiko Seiki SCU-21D is a universal electronic control unit engineered to drive and monitor 5-axis magnetically levitated (Maglev) turbomolecular pumps, particularly the STP-301 and related series. Originally developed by Seiko Seiki (whose turbopump division was later acquired by Edwards), this controller provides friction-free rotor suspension, eliminating the need for internal bearing lubrication and preventing hydrocarbon contamination in ultra-high vacuum environments.

This controller incorporates advanced Auto Vibration Reduction (AVR) and an Auto Balancing System (ABS). These technologies dynamically adjust magnetic suspension currents in real-time to counteract rotor imbalance, ensuring exceptionally smooth, low-vibration operation across all rotational speeds.

Technical Specifications

Compatible Turbo Pump Series

The SCU-21D is designed to pair with Edwards / Seiko Seiki medium-capacity maglev pumps, including:

• STP-301 Series: STP-301 (Standard), STP-301C (Corrosive-Spec), STP-301CVB

Key Features & Lab Benefits

• Total Oil-Free Operation: 5-axis active magnetic levitation completely removes mechanical bearing friction and wear, translating to near-zero maintenance cycles and zero oil backstreaming.

• Auto Vibration Reduction (AVR): Internal logic actively compensates for minor shifts in the pump's center of mass, delivering the ultra-low vibration profiles required for electron microscopy and sensitive surface analysis.

• Auto Balancing System (ABS): Stabilizes the rotor dynamically during both the critical run-up acceleration phase and high-gas-load processing.

• Battery-Free Emergency Braking: In the event of a facility power failure, the controller harvests back-EMF generated by the spinning rotor to keep the magnetic bearings powered while the pump safely decelerates.