Auxiliaries NIII_Z_5: Check Time Delay of MNR Delayed Undervoltage Release

Safety Instructions

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E, CSA Z462, NOM 029-STPS, or local equivalent. This equipment must only be installed and serviced by qualified electrical personnel. Unless specified otherwise in the maintenance procedures, all operations (inspection, test, and preventive maintenance) must be carried out with the device, the chassis, and the auxiliary circuits de-energized. Check that the device and the chassis are de-energized on the upstream and downstream terminals. Always use a properly rated voltage sensing device to confirm that the device, the chassis, and the auxiliary circuits are de-energized. Install safety barriers and display a danger sign. During the tests, it is strictly forbidden for anyone to touch the device, the chassis, or the conductors while voltage is applied. Before turning on power to this equipment, check that all connections are made with the correct tightening torque and the device is open (OFF position). Before turning on power to this equipment, put all devices, doors, and covers back in place. Before turning on power to this equipment, beware of potential hazards and carefully inspect the work area for tools and objects that may have been left inside the equipment. Failure to follow these instructions will result in death or serious injury.

DANGER

HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH

Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E, CSA Z462, NOM 029-STPS, or local equivalent.
This equipment must only be installed and serviced by qualified electrical personnel.
Unless specified otherwise in the maintenance procedures, all operations (inspection, test, and preventive maintenance) must be carried out with the device, the chassis, and the auxiliary circuits de-energized.
Check that the device and the chassis are de-energized on the upstream and downstream terminals.
Always use a properly rated voltage sensing device to confirm that the device, the chassis, and the auxiliary circuits are de-energized.
Install safety barriers and display a danger sign.
During the tests, it is strictly forbidden for anyone to touch the device, the chassis, or the conductors while voltage is applied.
Before turning on power to this equipment, check that all connections are made with the correct tightening torque and the device is open (OFF position).
Before turning on power to this equipment, put all devices, doors, and covers back in place.
Before turning on power to this equipment, beware of potential hazards and carefully inspect the work area for tools and objects that may have been left inside the equipment.

Failure to follow these instructions will result in death or serious injury.

Procedure Definition

Procedure characteristics	Description
Action	Check the time delay on the MN delay unit at 0.35 Un and 0.7 Un.
Goal	Verify that the MNR delayed undervoltage release is not activated before the end of the selected time delay.
Frequency	Refer to Recommended Frequency for the Intermediate End-User Maintenance Program.
Special indications	Connect the MNR delayed undervoltage release to an external power supply.
Necessary tools	Adjustable external power supply Voltmeter Stopwatch
Related documents	MasterPacT MTZ1 - IEC Switch-Disconnectors and Circuit Breakers with MicroLogic X Control Unit - User Guide MasterPacT MTZ2/MTZ3 - IEC Switch-Disconnectors and Circuit Breakers with MicroLogic X Control Unit - User Guide MasterPacT MTZ1/MTZ2/MTZ3 - MN-MX-XF Voltage Releases - Instruction Sheet MasterPacT MTZ1/MTZ2/MTZ3 - MN-MX-XF Communicating Voltage Releases with Diagnostic Function - Instruction Sheet

Preliminary Conditions

The device must comply with the conditions specified below. Refer to the MasterPacT MTZ User Guides to find instructions for operating the device.

Device installation type	Position of poles	Mechanism	Device position in the chassis
Fixed	Closed	Discharged	N/A
Drawout	Closed	Discharged	Test

Time Delay Definition

The time delay is the time elapsed between the opening order and the moment when the MNR delayed undervoltage release operates.

The time delay does not exceed the delay setting ±15%.

MNR Delayed Undervoltage Release Wiring Diagram

Checking the Time Delay of the MN Delay Unit During Device Opening

DANGER
HAZARD OF ELECTRIC SHOCK When using the adjustable external power supply, take all suitable measures to protect against electric shock. Failure to follow these instructions will result in death or serious injury.

Before starting this check, it is advised to execute a few electrical opening and closing cycles as per procedure Mechanism NII_Z_1.

Step	Action	Corrective action
1	Disconnect supply wires on the customer terminal block.
2	Connect the adjustable external power supply according to the corresponding wiring diagram above. NOTE: If possible, the opening time should be measured using the main connections. If that is not possible, carry out the measurement on an OF contact.
3	Set the external power supply voltage to 0.35 Un.
4	To start the stopwatch, remove the power supply or issue a delayed opening order.
5	The device opens when the time delay equals the delay setting on the MN delay unit. The stopwatch stops when the device opens.
6	Check the time delay on the stopwatch: it must equal the delay setting ±15%.	If the time delay differs by more than ±15% from the delay unit setting, replace the MN delay unit (refer to MasterPacT MTZ - MN-MX-XF Voltage Releases - Instruction Sheet) and do the procedure again. If the problem persists, contact your Schneider Electric Services representative.
7	Reconnect the external power supply to the MNR delayed undervoltage release, and then close the device.
8	Set the external power supply voltage to 0.7 Un.
9	To start the stopwatch, remove the power supply or issue a delayed opening order.
10	The device opens when the time delay equals the delay setting on the MN delay unit. The stopwatch stops when the device opens.
11	Check the time delay on the stopwatch: it must equal the delay setting ±15%.	If the time delay differs by more than ±15% from the delay unit setting, replace the MN delay unit (refer to MasterPacT MTZ - MN-MX-XF Voltage Releases - Instruction Sheet) and do the procedure again. If the problem persists, contact your Schneider Electric Services representative.
12	Reconnect the customer terminal block according to the initial wiring.
13	Check that the device electrically closes and opens according to procedure Mechanism NII_Z_1.