GE Industrial Solutions MX350 Instruction manual - Manual (Page 79)

CHAPTER 5: SETPOINTS CONFIGURATION SETPOINTS
MX350 AUTOMATIC TRANSFER CONTROL SYSTEM – INSTRUCTION MANUAL 5–5
SOURCE 1 POWER RESTORATION:
When Source 1 is recovering and reaches the presets as set up in the Setpoints >
Operations > S1 Settings screen, the controller initiates a re-transfer to Source 1. In order
to ensure that the utility voltage and frequency are stable before transferring back to
Source 1, the delay to Source 1 (T) timer begins to time for a period of time as set up by the
user, typically set to 30 minutes. If the user wishes to re-transfer before the T timer has
expired, he or she can highlight the timing message on the Status screen and bypass the
timer by depressing the Bypass soft key. When the T timer has timed out or the Bypass key
has been depressed, the controller will energize SCR-EO and the ATS will move to the
open/neutral position.
Once the switch is in the open position, the delay to Source 1 (DT) timer starts its timing
cycle. Upon completion of the DT timer, the energizes SCR-N in order to transfer the load
back to Source 1.
The controller maintains the engine start signal for the time period specified as the U timer
(delay to stop engine) in order to ensure proper cooling of the engine before shutting it
down. If the operator desires to turn off the engine before the U timer has expired, he or
she can highlight the timing message on the Status screen and bypass the timer by
depressing the Bypass soft key. When the U timer has timed out or the Bypass key has
been depressed, the engine start signal will be removed, causing the engine to shut down.
Closed transition GE Zenith Controls Closed Transition Transfer Switches are designed to transfer a load
between two available sources without interrupting power to the load, i.e. in a make-
before-break type manner. The actual paralleling of the two sources typically occurs
within a time period of 100 ms.
Closed Transition Transfer Switches are designed to transfer a load between two available
sources without interrupting power to the load, i.e. in a make-before-break type manner.
The actual paralleling of the two sources typically occurs within a time period of 100 ms.
In order for the controller to consider both sources synchronized, the following criteria
have to be met:
•
Phase Rotation: match
• Voltage difference: < 10%
• Phase Angle difference: < 10 degrees
• Frequency difference: < 0.2 Hz
SOURCE 1 POWER FAILURE:
When the Source 1 voltage or frequency has fallen below the values as set up in the
Setpoints > Operations S1 > Settings screen, the controller initiates the P timer (engine
start delay timer). Upon the completion of the P time delay, an Engine Start signal is sent to
Source 2, typically an engine generator set. When frequency and voltage of S2 reach the
values as set up in the Setpoints > Operations > S2 Settings screen, the W timer (time
delay to S2) begins timing. The W time delay ensures that source 2 is stable before actually
transferring to this source. If desired, the operator can bypass this timer from the Status
screen or through a remote signal. After the W time delay, the MX350 controller energizes
SCR-NO to move the switch to the open position, where the load is connected to neither
source.
Once the switch is in the open position, the delay to Source 2 (DW) timer starts its timing
cycle. Upon completion of the DW timer, the controller energizes SCR-E in order to transfer
the load to source 2.
SYSTEM TEST (S1 AVAILABLE):
When the system is performing a test, the MX350 controller sends an engine start signal to
Source 2. When frequency and voltage of S2 reach the values as set up in the Setpoints >
Operations > S2 Settings screen, the W timer (time delay to S2) begins timing. The W time
delay ensures that source 2 is stable before actually transferring to this source. If desired,
the operator can bypass this timer from the Status screen or through a remote signal.