Brochures and Data Sheets

Delayed Transition Transfer Switching
Fig. 3: Four pole, Delayed Transition
Transfer Switch rated 2000 Amperes.
ASCO Delayed Transition Transfer Switches are designed
to provide transfer of loads between power sources with a
timed load disconnect position for an adjustable period of
time. Applications include older style variable frequency
drives, rectifier banks, and load management applications.
• Available in 150 through 4000 Amperes.
• Utilizes reliable, field proven solenoid operating
mechanisms.
• Mechanical interlocks to prevent direct connection
of both sources.
• Indicator light (16mm, industrial grade
type LED) for load disconnect position.
• Adjustable time delay for load disconnect position.
Closed Transition Transfer Switching
ASCO Automatic Closed Transition Transfer Switches feature
main contacts that overlap, permitting the transfer of electrical
loads without power interruption. The switch transfers in a
make-before-break mode if both sources are within acceptable
parameters. Control logic continuously monitors source
conditions and automatically determines whether the load
transfer should be open (conventional non-overlap mode) or
closed transition. Available 150 through 4000 Amperes.
Closed Transition Transfer within 5 electrical degrees is achieved
passively, without control of engine generator set. Therefore,
no additional control wire runs are required between the ATS and
engine generator set governor. Plus, protective relaying may
not be required under normal operation since the contact over-
lap time is less than 100 milliseconds (consult your local utility
on protective relay requirements).
Failure to synchronize indication and extended parallel time
protection is built-in to all 7000 SerieS closed transition
controls to prevent abnormal operation.
Fig. 2: Four pole, Closed Transition Transfer Switch
rated 1000 Amperes in Type 1 enclosure.
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7000 series Power Switching Solutions