Ge ZTGD Series Transfer Switches 40-3000 Amps User Manual download pdf (Page 21)

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GE Zenith Controls 21

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ZTG/ZTGD Operation and Maintenance Manual (70R-1000D)

Sequence of Operation

Standard Transition

Source 1 Power Failure:

When Source 1 voltage or frequency has fallen below

the preset "Fail" values, the controller initiates the Time

Delay Source 2 Start Timer (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 Source 2 Timer (W) begins its timing

cycle to ensure voltage and frequency stabilization

before transfer. A manual pushbutton BYPASS is provided

to bypass the "W" time delay if desired. After the (W)

time delay, the MX controller initiates a transfer signal

through the SCR-E to operate the main transfer operator.

The load is now transferred to Source 2 line. The transfer

switch is mechanically locked. SN limit switch awaits the

next operation to Source 1.

Restoration of Source 1 Power:

When Source 1 power reach the preset "Restore" values,

the controller initiates re-transfer to Source 1sequence.

The delay to Source 1 Timer (T) begins its timing cycle

to ensure voltage and frequency stabilization before

retransfer. A manual pushbutton BYPASS is provided to

bypass the "T" time delay if desired. After the (T) time

delay, the MX controller initiates a transfer signal

through the SCR-N to operate the main transfer opera-

tor. The load is now transferred to Source 1 line. The

transfer switch is mechanically locked. SE limit switch

awaits the next operation to Source 2.

Immediately after re-transfer, the S2 Stop Delay Timer

(Delay to Engine Stop "U") begins its cycle to allow

Source 2 Engine to run unloaded. A manual pushbut-

ton BYPASS is provided to bypass the "U" time delay if

desired. Upon completion of the (U) timing cycle, the

controller sends an Engine stop signal.

Delayed Transition

Source 1 Power Failure:

When Source 1 voltage or frequency has fallen below the

preset "Fail" values, 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 to ensure

voltage and frequency stabilization before re-transfer. A

manual pushbutton BYPASS is provided to bypass the

"W" time delay if desired. After the (W) time delay, the

MX controller initiates a transfer signal through the

SCR-NO to operate the main transfer operator. The

load is now transferred to the Open position. The time

delay to Source 2 timer (DW) begins its timing cycle.

After the (DW) time delay, the MX controller initiates a

transfer signal through the SCR-E to operate the main

transfer operator. The load is now transferred to Source

2 line. The transfer switch is mechanically locked. SN

limit switch awaits the next operation to Source 1.

Restoration of Source 1 Power:

When Source 1 power reach the preset "Restore" values,

the controller initiates re-transfer to Source 1 sequence.

The delay to open Source 2 Timer (T) begins its timing

cycle to ensure voltage and frequency stabilization before

retransfer. A manual pushbutton BYPASS is provided to

bypass the "T" time delay if desired. After the (T) time

delay, the MX controller initiates a transfer signal through

the SCR-EO to operate the main transfer operator. The

load is now transferred to the Open position. The time

delay to Source 1 timer (DT) begins its timing cycle.

After the (DT) time delay, the MX controller initiates a

transfer signal throught the SCR-N to operate the main

transfer operator. The load is now transferred to Source

1 line. The transfer switch is mechanically locked. SE

limit switch awaits the next operation to Source 2.

Immediately after re-transfer, the S2 Stop Delay Timer

(Delay to Engine Stop "U") begins its cycle to allow

Source 2 Engine to run unloaded. A manual pushbut-

ton BYPASS is provided to bypass the "U" time delay if

desired. Upon completion of the (U) timing cycle, the

controller sends an Engine stop signal.

Timer Designations as they appear in the SET menu

ATS Type P W DW T DT U

Standard Time Delay Time Delay Time Delay S2 Stop

S2 Start S2 Stable S1 Stable Delay

Delay Time Delay Time Delay ATS Open Time Delay ATS Open S2 Stop

S2 Start S2 Stable Time to S2 S1 Stable Time to S1 Delay

Source 1 Transfer to Source 2

Source 1

Transfer to Source 1 Engine

Fails

Returns

Cooldown

Table 3

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 35 36

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Ge ZTGD Series Transfer Switches 40-3000 Amps User Manual Page 21

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