GE Entelli-Switch 250 manual Emergency Service Procedure for Extended Parallel Time, Auto Location

Testing (cont’d)

DANGER

HAZARDOUS VOLTAGE

(Can Cause Severe Injury or Death)

Turn OFF all power before installation, adjustment, or removal of transfer switch or any of its components.

Emergency Service Procedure for Extended Parallel Time

ZTSCT Transfer Switch

If Source 2 breaker shunt trip was triggered after an extended parallel time (malfunction) occurred. Follow these steps to open the transfer switch.

1)Disconnect all power sources from the transfer switch by opening all line breakers

(Source 1 and Source 2).

2)Open the cabinet door and turn the disconnect switch to the INHIBIT position.

3)Remove the service access cover on the left hand side of the transfer switch.

4)The manual operator and the manual handle will now be exposed. Insert the handle into the Source 2 side operator. Open the Source 2

side contacts.

5)Close the cabinet door.

6)Energize Source 1 to supply the load until further repairs can be done.

ZBTSCT Transfer/Bypass Switch

a. Auto Location:

Removal of closed transition transfer switch after Source 2 breaker shunt trip.

1)Disconnect all power sources from bypass- isolation transfer switch.

2)Open the bottom cabinet door and turn the Disconnect Switch (DS) to the INHIBIT position.

3)Remove the service access cover on

the left hand side of the transfer switch.

4)The manual operator and the manual handle will now be exposed. Insert the handle into the Source 2 side manual operator. Open the Source 2 side contacts.

5)Close bottom cabinet door.

6)Energize Source 1 power.

7)Close the bypass contacts (BN).*

8)Isolate the transfer switch.*

9)Remove the transfer switch from the bypass- isolation transfer switch as indicated on the bypass instruction label to inspect and repair.

10)Re-install the transfer switch after maintenance with contacts closed to the same source as the bypass switch. Reinstall the manual handle in its holder and the service access cover on the left side of the transfer switch.

11)Re-connect the transfer switch to AUTO.*

b. Auto Location:

Removal of the closed transition transfer switch if Source 1 and Source 2 contacts remain open.

1)Close the bypass switch into the available source.*

2)Turn the DS to INHIBIT. Remove the transfer switch service access cover. Close the transfer switch into the same source as the bypass switch. (Incorrect sequencing is prevented by the interlocks while the transfer switch is in AUTO only.)

3)Remove the transfer switch from the bypass- isolation transfer switch to inspect and repair.*

c.Test Location:

Removal of the closed transition transfer switch if both Source 1 and Source 2 contacts remain open.

1)Close the bypass switch contacts (BN) as indicated on the bypass instruction label on the cabinet door.

2)Disconnect all power sources from bypass-isolation closed transition transfer switch.

3)Open bottom cabinet door. Turn the Disconnect Switch (DS) to the INHIBIT position.

4)Remove the service access cover on the left side of the transfer switch.

5)The manual operator and the manual handle will not be exposed. Insert the handle into the Source 1 side and close the Source 1 contacts.

6)Close the bottom cabinet door.

7)Energize Source 1 power.

8)Remove the automatic transfer switch from the bypass-isolation transfer switch.*

9)Re-install the transfer switch after maintenance with contacts closed to the same source as the bypass switch. Reinstall the manual handle in its holder and the service access cover on the

left side of the transfer switch. 10)Re-connect the transfer switch to AUTO.*

* As described in the Sequence of Operation section located in the ZTSCT/ZBTSCT Series Manual (71R-5000)

■ GE Zenith Controls Entelli-Switch 250 Operation and Maintenance Manual (71R-2000) 23 ■