Phase failure Protection Relay

one of the common faults faced in industrial plants is overheating and damaging of 3 phase motors due to the phase failure.

phase

1.Phase Faliure

When the monitored 3 phase voltages are valid, the output relay is activated:if any of 3 phases fails, the output device switchrs as OFF immediately. Relay LED is OFF,Asymmetry and Phase sequence error LEDs are ON.

2.Phase Sequence

when the phase sequence is correct(L1,L2,L3 in clockwise direction) the output relay is activated:however, if the sequence is changed by any reason, the output relay switches OFF immediately. Relay LED is OFF, Phase sequence error LED is ON.

3.PTC Protection(only available in MK-05p,MKC-05p,MKC-06p&MK-06p versions)

When the coiltemperature in motors exceeds TC,the limit temperature of PTC, the outputrelay switches off immediately,relay LED is OFF, this feature is included only in MK-05p,MK-06p andMKC-06p.

See following figure for typical resistance of PTC vs temperture characteristics for three different switching temperatures(110°c,120°c,130°c).Normally,PT110 is used and it can be changed upon request.

4.Voltage Unbalance(Both Unbalance and Delay Adjustable)

When the phase-phase voltage unbalance is less than the adjusted value by the user,output relay is activated. If the unbalance value exceeds the limit value(5%-15%)set by the user,out put relay is switched OFF at the end of delay time(0.1...10s)that is also set by the user.

Relay LED is OFF, asymmetry error LED is ON. If the fault disappears within the delay time, the output relay is not swithed OFF.

The voltage unbalance occurs if the phases L1,L2,L3 are loaded unequally,this case is caused by a non-uniform distribution of loads on the lines.

The voltage asymmetry causes rise in of the motor temperature and a reduction of the rated motor power.

Voltage asymmetry limit values are adjusted(5%-15%)by the user.

Hysteresis is fixed at 20%.

5.Insufficient Supply

L1 is the supplyphase of the MK-05 and MK-05P in PK21 package while.

L3 is the supply phase of MKC-05 and MKC-05p devices.For Mk and MKC devices if supply voltage fallsbelow 60-65% of rated voltage, output relay switches off without delay and error leds start to blink one after another sequentially.

1.On LED

2.Output LED

3.Phase sequence fault LED

4.Asymmery fault LED(While LED number 3and4 are On at the sametime, it means there is phases failure)

5.Contact3 normally ON connection of output relay

6.Contact2 common connection of output relay

7.contact1 normally OFF connection of output relay

8.Time adjustment(0.1sec-10sec.)

9.Asymmetry adjustment(5%-15%)

10.L1.L2.L3. phase connection

11.Neutral connection(only for 05and05p series)

12.PTC connection**:Only available in MK-05p.MKC-05p

If PTC is not used in MK-06p,MKC-06p by any reason,the PTC terminals should be short circuited.

Technical Data

Rated Voltage(un):

220vac(MK-05/05p.MKC-05/05p)

3 phase+neutral:4wires connection

120VAC(MKC-05/05P Special design)

3phase+neutra:4 wires connection

380VAC(MK-06,MKC-06)

3phase:3 wires connection

440VAC(MKC-06/06P Special design)

3 phase:3 wires connection

The three phase network being protected is used as the device power supply.

Operating Range :(0.9-1.1)xUn

Rated Frequency:50/60Hz

Output Contacts:1C/O with 8A,2000VA(for resistive load)

Asymmetry Range:5%-15%:3*380VAC

Diemnesions:

  Type PK10(forMk-05/05p,Mk-06/06p)type pk21(for mk-05/05p) type pk25(for mkc05/05p,mkc-06/06p)

  weight:0.3KG.0.2kg.

Phase failure Protection Relay