19862002 Schneider Electric All Rights Reserved 1

INTRODUCTION The Class 8430 Type MPD phase failure relay is a three-phase voltage sensing device that trips on phase loss, phase reversal, voltage unbalance, or undervoltage. Voltage unbalance trips the device when any voltage drops 10% below the average. Undervoltage is externally adjustable from 75100% of the rated voltage. The LED on the front of the device lights when the device is energized.Two 600 V Form C output contacts are standard on all devices. Table 1 shows the input voltage and input burden for each device type.

MOUNTING For surface mounting, use two 8-32 screws placed 3.125 in. (79 mm) apart. Mount adjacent devices on 2.25 in. (57 mm) centers. Class 8501 TYPE X mounting track can be used.Terminals accept one 1814 AWG copper wire. Use wire with 75 C or higher insulation. Torque to 79 lb-in (0.81.0 Nm).

Table 1: Device Types

Type Input Voltage (60 Hz, 3 phase) Input BurdenMPDV20 120 Vac 5.0 VA maximumMPDV24 240 Vac 5.5 VA maximumMPDV29 480 Vac 6.5 VA maximumMPDV32 600 Vac 7.0 VA maximum

DANGER WARNINGHAZARDOUS VOLTAGETurn off all power supplying this equipment before working on it. Failure to follow this instruction will result in death or serious injury.

UNEXPECTED RESTART This phase failure relay has auto reset. Do not use a maintained contact device to control the motor starter.Failure to follow this instruction can result in death or serious injury.

Figure 1: Terminal Connections Figure 2: Approximate Dimensions

Shows the position of the output contacts when the relay is de-energized.

Instruction Bulletin65013-008-89A

08/2002Raleigh, NC, USA

Replaces 65013-008-89 6/86

Phase Failure RelayClass 8430 Type MPDRetain for future use.

19862002 Schneider ElectricAll Rights Reserved

Phase Failure Relay, Class 8430 Type MPD 65013-008-89AInstruction Bulletin 08/2002

2

CONNECTION DIAGRAMS

Table 2: Temperature Ratings Table 3: Contact Ratings

Temperature, F (C)Contacts

Control Circuit Voltage

AC RatingsMinimum Maximum Inductive Resistive Thermal

ContinuousOperating Ambient Air 23 (5) 122 (50) Make Break Make and Break Storage 4 (20) 158 (70) DPDT

(double pole, double throw)

600 V480 V240 V120 V

3600 VA3600 VA3600 VA3400 VA

360 VA360 VA360 VA340 VA

2.5 A2.5 A5 A5 A

5 A5 A5 A5 A

The air temperature in the immediate vicinity of the device, into which the heat of the device dissipates.

OPERATION Upon application of the proper three-phase voltage, the relay energizes and the LED turns on. When one of the following incorrect conditions occurs, the LED turns off and the relay de-energizes: Phase lossLoss of phase A, B, or C Phase reversalPhase rotation other than A-B-C Voltage unbalanceAny of the three line voltages is more than 10%

below the average of the three line voltages UndervoltageThe average of the three voltages is less than the set

level.The relay remains de-energized and the LED turned off as long as the improper condition continues. When the condition is corrected, the relay automatically re-energizes and the LED turns on.

Table 4: Operating CharacteristicsUndervoltage Adjustment

120 V240 V480 V600 V

Range90120 V180240 V360480 V460600 V

Pickup Time Typically 0.1 s when the correct three-phase voltage is applied

Dropout Time Typically 3.0 s for any incorrect voltage condition

Transient Protection 5000 V for 50 s

WARNING CAUTIONUNEXPECTED MOTOR REVERSAL All functions of the phase failure relay are

bypassed while the start button is depressed.

Do not use load side monitoring if motor reversal is not required.

Unexpected motor reversal can result in death or serious injury.

EXCESSIVE MOTOR BACK-EMFHigh levels of Back-EMF (electromotive force) on larger motors can supply sufficient voltage to prevent this relay from detecting a phase loss. Always use a motor overload protection device. Do not use this relay as your only phase loss protection.Failure to follow this instruction can result in equipment damage.

Figure 3: Load Side Monitoring Figure 4: Line Side Monitoring

OL

MOTORM

M

MA

B

C

ABC 8

430

MPD

M8430MPD

STOPSTARTL1 L2

MOTORM

M

MA

B

C

ABC 8

430

MPD

MM

8430MPD OLSTOP

STARTL1 L2

NOTE: Line side monitoring does not protect against high resistance contacts on the contactor.

Electrical equipment should be installed, operated, serviced, and maintained only by qualified personnel. No responsibility is assumed by Schneider Electric for any consequences arising out of the use of this material.

Square D Company8001 Highway 64 EastKnightdale, NC 275451-888-SquareD (1-888-778-2733)www.SquareD.com