CAT LEHE4651-04 User Manual

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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.