Specifications

Series 300
Automatic Transfer Switch
Electrical Features:
• 600 volt spacing per UL and CSA standards.
• Interfacing relays are industrial grade, plug-in type
with dust covers.
• Meets or exceeds the requirements for
Electromagnetic Compatibility (EMC).
• ANSI C37.90A/IEEE472 Voltage Surge Test
• NEMA ICS-109.21 Impulse Withstand Test
• Digital circuitry isolated from line voltages
• IEC 801-2 Electrostatic discharge (ESD) immunity
• ENV50140 and IEC 803-1: Radiated electromagnetic
field immunity
• IEC 801-4 Electrical fast transient (EFT) immunity
• ENV50142 Surge transient immunity
• ENV50141: Conducted radio-frequency field
immunity
• EN55011: Group 1, Class A conducted and radiated
emissions
• Optically isolated RS-485 Serial Port
• EN61000- 4-11 voltage dips and interruptions
immunity.
The ASCO Microprocessor Controller is used with all sizes of Power
Transfer Switches. It represents the most reliable microprocessor
controller in the industry and includes, as standard, all of the voltage,
frequency, control, timing and connectivity functions required for most
emergency and standby power applications.
The easy-to-read flush-mounted
control and display panel
provides LED indicators for
switch position and source
availability. It also includes test
and time-delay bypass
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 Selectable Features
• Inphase 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.