Brochures and Data Sheets

Control and Display Panel
Easy-to-read flush-mounted control and display panel
provides LED indicators for switch position and source avail-
ability. It also includes test and time-delay bypass switches.
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.
Re-transfer 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 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 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 adjustable time delay prior
to transfer and reset 0 to 20 seconds after transfer.
60 Hz or 50 Hz selectable switch.
Three-phase/single-phase selectable switch.
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.
Remote time-delay bypass switch.
Fig. 8: ASCO SerieS 300
Microprocessor Controller
6
Fig. 9: Door-Mounted Control & Display Panel
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.
series 300 Microprocessor Controller