CAT LEHE4651-04 Switch User Manual


 
AUTOMATIC TRANSFER SWITCH
LEHE4651-04
3
NEUTRAL SWITCHING
The CTS Series is available in true four pole designs
for multi-source power systems that require switching
the neutral. The neutral contact is on the same shaft
as the associated main contacts. This design ensures
positive operation, and prevents any possibility that
the neutral contact will fail to open or close, as is
possible when the neutral pole is an add-on
accessory. The neutral contacts are identical to the
main contacts, having the same current carrying and
high withstand /closing ratings as the mains. They are
designed to break last and make first to negate the
possibility of transients while switching the neutral.
SAFE MANUAL OPERATION
The CTS manual operator consists of a large,
easy-to-use handle that fits securely for manual
operation during installation and maintenance
or in an emergency.
Every CTS is provided with an operator inhibit
switch to disconnect the electrical drive prior to
maintenance. Fully enclosed wrap-around arc
covers shield the main contacts and mechanical
components, preventing operator exposure during
manual operation
TRANSFERRING LARGE MOTOR
OR HIGHLY INDUCTIVE LOADS
Some loads, especially large motors receive
severe mechanical stress if power is transferred
out of phase while the motor is still rotating.
Also, back EMF generated by a motor can result
in over currents that can blow fuses or trip circuit
breakers. The CTS Series offers four solutions
to these problems:
1. Optional Universal Motor Disconnect Contact:
This load control disconnects a large motor via
its control circuit for an adjustable period of time
prior to transfer in either direction. For switching
multiple motors, the motor disconnect contact
with staged restart disconnects the motors
prior to transfer and brings them back on line
sequentially.
2. Accessory R50 Phase Monitor: This feature
compares the phase angle between both sources
of power and prevents transfer until the two are
approximately in phase (within a self adjusting
range). The CTS’s high speed transfer action
coupled with the MX series microprocessor
control logic ensure closures at or near zero
degree phase difference
CTS SERIES ATS
400 amp, 2 pole
3. Series CTSD: The CTSD offers a delayed
transition on transfer switches 40A and above.
This programmed center-off position allows for
the full decay of rotating motors or transformer
fields. It can also be used for load shedding
of selected circuits or other applications which
require a means to disconnect the load from
either source. Many UPS system manufacturers
recommend delayed transition switches to
support sequencing of their systems. Reference
the CTSD supplement for further details.
4. Series CTSCT: Cat closed transition
switches combine CTSD operation during a
source failure with a highly engineered control
system that allows momentary paralleling (100
ms) of two acceptable sources, thereby limiting
the impact of transfer on the load. Reference
the CTSCT supplement for further details.