>Z-Cap Zero Voltage Closing Control (ZVC)

Valquest Systems, Inc. introduces the Z-Cap™ "Zero Voltage Closing" (ZVC) Capacitor Switch Control to meet the Smart Grid demands of the Electrical Distribution Community.

The Z-Cap is one of the most efficient methods of controlling switched capacitor banks. Zero voltage closing significantly improves power quality, eliminates voltage transients, reduces both capacitor inrush currents and voltage peak surges, and diminishes harmonic distortion. To achieve zero voltage closing of an entire capacitor bank, the Z-Cap initiates a separate close operation, per phase, synchronized with zero crossing. Zero voltage closing performance is maintained through ongoing automatic switch calibration and adjustment for temperature and wear.

The Z-Cap is ideally suited for use in conjunction with Valquest’s VAr-min Capacitor Control as well as a wide variety of controls from other manufacturers. It is compatible with solenoid-operated switches from leading switch manufacturers such as Maysteel, Joslyn and Cooper. This versatility combined with its low cost make it the premier control to meet your power quality requirements.

Closing each capacitor switch at precisely the right time,
Z-Cap effectively:

  • Eliminates switching related voltage transients
  • Improves power quality
  • Diminishes harmonic distortion
  • Lowers voltage peak surges
  • Increases capacitor life by reducing inrush currents

Accuracy is unparalleled

  • Independent temperature compensation of local closing caps and bank switches
  • Microprocessor based solenoid operation analysis
  • Precisely controlled local closing energy storage
  • Digital waveform analysis
  • Automatic timing self adjustment based on closing feedback
  • Line frequency monitoring

Bonus Features

  • Compatible with any capacitor control or PLC
  • Works with Maysteel, Joslyn, and Cooper solenoid operated switches
  • Provides 52A Status and Control-Ready dry contact signals back to controlling device
  • Digital control, monitoring and data storage available via RS-232 port

Technical Specifications

Parameter Range Units
Operating Temperature -20 to 145 Degrees F
Humidity (Non-Condensing) 0 to 100 Percent
Operating Voltage 110 to 140 VAC
Power Usage 2 Watt
Enclosure NEMA 4 Polycarbonate
Closing Accuracy +/- 0.45 Millisecond


Bank Rotation Voltage
Single Phase   Phase-Neutral
Three Phase Grounded Y ABC Phase-Neutral
Three Phase Grounded Y ABC Phase-Phase
Three Phase Grounded Y CBA Phase-Neutral
Three Phase Grounded Y CBA Phase-Phase
Three Phase Un-Grounded Y ABC Phase-Phase
Three Phase Un-Grounded Y CBA Phase-Phase

Examples of recorded voltage waveforms (contacts closed at time 0)

Without Z-Cap Using Z-Cap