Operating the Device

Device Status

The indicators on the front of the device show the following information:

Reset button:
- In: the device is closed or open voluntarily (not tripped)
- Out: the device has tripped
Position indicator of main contacts: ON or OFF.
Closing spring and ready-to-close indicator. The state can be one of the following:
- Discharged (no energy to close the circuit breaker)
- Charged not ready-to-close
- Charged ready-to-close

A Reset button

B Position indicator of main contacts

C Closing spring and ready-to-close indicator

The combination of both indicators gives the device status:

Position indicator of main contacts	Closing spring and ready-to-close indicator	Device status description
		Device is off (main contacts are open) and closing spring is discharged.
		Device is off (main contacts are open) and closing spring is charged. The device is not ready-to-close because at least one of the following conditions is true: The device has tripped and must be reset. The MX opening voltage release is energized. The MN undervoltage release is not energized. The device is mechanically locked in the open position by using padlock or keylock or by using an interlocking system.
		Device is off (main contacts are open) and closing spring is charged. The device is ready-to-close.
		Device is on (main contacts are closed) and closing spring is discharged.
		Device is on (main contacts are closed) and closing spring is charged. The device is not ready-to-close because it is already closed.

Device Indication Contacts

The position of the device main contacts is indicated by OF indication contacts.

Name	Contact number	Position of indicators and contacts
Device status	–	ON	OFF	Tripped (by MicroLogic X control unit)
Position indicator of main contacts	–
Main contact position	–	Closed	Open	Open
Reset button position	–	IN	IN	OUT
OF indication contact position	1–2	Open	Closed	Closed
OF indication contact position	1–4	Closed	Open	Open
SDE indication contact position	1–2	Closed	Closed	Open
SDE indication contact position	1–4	Open	Open	Closed

Anti-Pumping Function

MasterPacT MTZ devices provide a mechanical anti-pumping function. In the event of simultaneous maintained opening and closing orders, the standard mechanism blocks the main contacts in the open position. After a trip due to an electrical fault or intentional opening using the manual or electrical controls, the closing order must first be discontinued, then reactivated to close the circuit breaker. This prevents a cycle of closing and opening.

When remote operation features are used, allow at least four seconds for the MCH gear motor to charge the device closing spring completely before the XF closing voltage release is actuated.

To prevent the device from closing prematurely, the PF ready-to-close contact can be series connected with the XF closing voltage release.

Charging the Closing Spring

The closing spring must be charged with sufficient energy to close the MasterPacT MTZ device:

Manual charge: Charge the mechanism by pulling the spring charging handle down seven times.
Automatic charge: If the optional MCH gear motor is installed, the spring is automatically charged after closing.

Manual Operation Cycle with the Spring Charging Handle

The following image shows an Open/Close/Open (OCO) cycle for manually charged devices without MCH gear motor:

Electrical Operation Cycle with an MCH Gear Motor

The following image shows an Open/Close/Open (OCO) cycle for electrically charged devices using an MCH gear motor: