Table of Contents
Advertisement
Closed Transition
DANGER
Hazardous Volatge Can Cause
Severe Injury Or Death
Manual close contact operations ONLY when opposite
source contacts are open.
Failure to comply with these instructions
will result in death or serious injury.
WARNING
Improper Installation
Operation and Maintenance
service and maintain all electrical equipment.
DISCONNECT all power sources prior to installation,
operation, service and maintenance of all electrical
equipment. These activities shall be performed only by
DO NOT ATTEMPT TO PERFORM MANUAL
OPERATIONS OF AUTOMATIC TRANSFER
SWITCH IN CLOSED TRANSITION MODE.
Only use the Charging Handle to perform manual
operations of the Transfer Switch. No motorized
device shall be used as a substitute.
Failure to comply with these instructions
could result in death or serious injury.
ABB Zenith Closed Transition Transfer Switches are designed
to Transfer the Load between two available sources
without interrupting power to the Load (Make-Before-
Break). Paralleling of the two sources occurs within a
100 milliseconds. The initial Source is then disconnected.
Initiating a Closed Transition
When a Test is initiated, the controller initiates the Time
Delay Source 2 Start (Engine Start Timer "P") cycle. Upon
completion of the (P) time delay, an Engine start Signal is sent
to Source 2. When Source 2 voltage and frequency reach
the preset "Restore" values, the time delay to open Source 1
timer (W) begins its timing cycle. After the (W) time delay, the
ATS closes into Source 2 only after the controller ensures the
proper phase relationship between the two Sources. After
the ATS closes into Source 2, the SE limit switch becomes
activated. The controller initiates a transfer signal through
the Relay Driver Module which opens the ATS out of Source
1. The SNO limit switch activates. The ATS has now closed
into Source 2 position without interrupting the load.
Zenith Automatic Transfer Switch
| new.abb.com/low-voltage
Retransfer with Closed Transition
Deactivating the Test Switch initiates the re-transfer. When
Source 1 voltage and frequency reach the preset "Restore"
values, the time delay to open Source 2 timer (T) begins its
timing cycle. After the (T) time delay, the ATS closes into
Source 1 only after the controller ensures the proper phase
relationship between the two Sources. After the ATS closes
into Source1, the SN limit switch Source 1 position without
interrupting the load. The ATS defaults to an open transition
transfer when Source 1 fails. Closed transition transfer is
not possible with only one source available. If the optional
Transition Mode Selector (TMS) is available, one can select
an Open Transition Transfer or a Closed Transition Transfer
when both Sources are available. If while in Closed Transition
Mode, the ATS fails to open the source it is attempting to
"transfer out of " within 100 milliseconds, an Alarm will sound
and the source that the ATS just closed into will be opened
leaving the ATS in its initial source while disabling all other
transfer operations until the problem is corrected and the
"Fail to Open Lockout Reset" has been pressed. A signal will
be provided (STE) to Shunt Trip the Generator Circuit Breaker
if the Transfer Switch remains closed into both Sources for
more than 325 milliseconds. The load will then be fed by the
Source 1. The maximum time that the two Sources would be
parallel, under these conditions, is less than 500 milliseconds.
Before operating the Closed Transition Transfer Switch, the
condition must be corrected and the Shunt Trip reset. Refer to
procedure for servicing the Switch after Shunt Tripping occurs.
• The unit is Factory set to accomplish transfer within 10
electrical degrees.
• Requires an Isochronous Governor with an operating
frequency of 60+/- 0.2 Hz.
• Requires a Shunt Trip Breaker on the Generator set with a
response time not exceeding 50 milliseconds.
16
Advertisement
Table of Contents
