ASCO Control Panel Standard Features & Design Criteria - Series 300

• Motor load transfer controls (in-phase monitor) to keep motors operating during transfer.
• Pre-transfer & post-transfer load disconnect contacts for signaling motor starters, elevators, VFDs and other selected loads.
• Standard Engine Exerciser for weekly automatic testing of engine generator set with or without load.
• Selectable control switches for voltage, frequency, time delay settings & additional control features.
• Switch position lights, source availability lights, test switch and time delay bypass switch.\

  Standard Selectable Features

  • In-phase monitor to transfer motor loads, without any intentional off time to prevent motor inrush currents from exceeding normal starting levels.
  • Engine exerciser to automatically test backup generator each week. Includes control switch for testing with or without load.
  • Selective load disconnect, double-throw contact to operate at an adjustable 0 to 20 second time delay prior to transfer and reset 0 to 20 seconds after transfer.
  • 60 Hz or 50 Hz selector switch.
  • Three-phase/single-phase selector switch.

  Voltage & Frequency Sensing

  • Adjustable three-phase, close differential voltage sensing on normal source.
  • Normal source pickup voltage is adjustable to 95% of nominal; drop-out is adjustable from 70 to 90% of nominal.
  • Frequency sensing on emergency source. Pickup at 95% and dropout at 85% of nominal.

  Time Delays

  • Adjustable time delay to override momentary normal source outages to delay all transfer switch and engine-starting signals.
  • Transfer to emergency time delay. Adjustable from 0 to 5 minutes for controlled timing of load transfer to emergency.
  • Retransfer to normal time delay. Adjustable to 30 minutes.
  • Five-minute unloaded running time delay for emergency engine generator cool down.
  • Four-second time delay to override momentary to ignore momentary voltage and frequency transients during initial genset loading.

  Standard Control Contacts

  • Switch position indicating contacts (rated 10 amps 250VAC, 32VDC). (1) for Normal position, (1) for Emergency position.
  • Gold plated engine start contacts (rated 5 amps 28VDC or 120VAC)

  Remote Control Features

  Terminal provisions for connecting:

  • Remote test switch.
  • Remote contact for test or for peak shaving applications. Circuit will be automatically bypassed if emergency source fails.
  • Inhibit transfer to emergency.
  • Remote time-delay bypass switch.

• EN61000-4-2:1995 Electrostatic discharge (ESD) immunity.
• ENV50140:1993 Radiated electromagnetic field immunity.
• EN61000-4-4:1995 Electrical fast transient (EFT) immunity.
• EN61000-4-5:1995 Surge transient immunity.
• ENV50141:1993 Conducted radio-frequency field immunity.
• EN55011:1991 Group 1, Class B conducted and radiated emission.

Additional Design Criteria:

• ANSI C37.90/IEEE472 Voltage Surge Test.
• NEMA ICS-109.21 Impulse Withstand Test.
• Digital circuitry isolated from line voltages.
• Optically isolated RS485 Serial Communications Interface (Acc. 72A).