General
One of the common faults faced in industrial plants is over-heating and burning of
3 phase motors due to the phase failure. Thermic-magnetic device which is an
essential element in motor protection is generally too slow due to both its electro-
mechanical structure and the use of high current setting range to assure demarrage
without tripping. Being designed to eliminate the above disadvantages, MKC-03A
(with neutral connection ), MKC-04A (without neutral connection) Phase Failure
Devices react within 0.2 seconds (fixed) against the following faults and take the
motor out of service.
PHASE FAILURE and PHASE SEQUENCE DEVICES
MKC-03A, MKC-03L, MKC-04A
A4946 / Rev.2
Dimensions
PRECAUTIONS FOR INSTALLATION AND SAFE USE
Failure to follow those instructions will result in death or serious injury.
Disconnect all power before working on equipment.
When the device is connected to the network, do not remove the front panel.
Do not try to clean the device with solvent or the like. Only clean the device
with a dried cloth.
Verify correct terminal connections when wiring.
Electrical equipment should be serviced only by your compedent seller.
Mount device to the panel.
Technical Data
Rated Voltage (Un)
: Please look at labels on the device.
: 3 phase and neutral 220-230 VAC
4 wire star connection (for MK-03/03P, MKC-03/03A/03P)
: 3 phase 380 VAC
3 wire delta connection
(for MK-04/04P, MKC-04/04A/04P, MKC-03L)
: 3 phase 220 V AC
3 wire delta connection (for MKC-04/04P)
Auxiliary Supply Voltage : 190-260 V AC (for only MKC-03L)
Operating Range
: (0.9-1.1) x Un
Rated Frequency
: 50/60 Hz
Output Contacts
: 1 C/O with 8A, 250 VAC, 2000 VA, Cos
j
=1
1 C/O with 0.5A, 125 V AC, 62.5 VA, Cos
j
=1 (for only MKC-03L)
Warning LEDs
: LED Output, normally ON (OFF for any fault)
*LED PTC turns ON when motor winding temperature exceeds 110
o
C
Tripping Time
: 0.2 s
Ambient Temperature :-5 °C to +50 °C
Protection Class
: IP 20
Dimensions
: Type PK 25 (MKC-03A, MKC-03L, MKC-04A)
Type PK 28 (MKC-03A, MKC-04A)
Installation
: Surface mounting or on the
mounting rails
Weight
: 0.2 kg
Terminal Cable Crosssections: (for PK-28)
4mm² (12AWG) solid conductor
6mm² (10AWG) stranded rigid conductor
2x2.5mm² (14AWG) solid conductor
(for PK-25)
4mm² (12AWG) solid conductor
2,5mm² (14AWG) stranded rigid conductor
2x1,5mm² (2x16AWG) solid conductor
Function Diagram
Fixed unbalance value
Hysterisis
L1
L2
L3
Output Relay
TD = Tripping time
TD
TD
Wrong Phase sequence
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.
The voltage asymmetry causes the rise in motor temperature and a reduction of
the rated motor power.
1. Voltage Unbalance (Not Adjustable)
MK-04 includes no neutral connection.
When the neutral-phase voltage unbalance is greater than 40% (fixed), the output
relay is activated and switched OFF the motor. Devices that have fixed voltage
unbalance between 5%-15% can be producted for special order.
Unbalanced voltage may occured when;
The mains are loaded with unbalanced distribution,
One of the 3-phase of motor has lost. In this case, some amount of voltage which
produced by other phases will be inducted on the lost phase. Amount of this value
depends on both the motor type and amount of load.
Output relay is activated when a phase has lost or an unbalanced phase-neutral
value, which is occured with any reason, is smaller than the Asymetrical value which
is defined for the device. If this unbalanced voltage exceeds the adjusted Asymetrical
value, output will release itself and motor will be Switched-off.
In Applications; a proper device must be used regarding to the inducted voltage
value in two-phase which are remained after the other one has lost.
No responsibility is assured by the manufacturer or any of its subsidiaries
for any consequences arising out of the use of this material.
TYPE PK28
48 mm
34 mm
90 mm
35.3 mm
59.7 mm
45.4 mm
61.8 mm
36 mm
TYPE
PK25
35 mm
90 mm
45 mm
62 mm
58 mm
32 mm
48 mm
35 mm
Connection Diagrams PK-25
Connection Diagrams PK-28
Vin (L-L)
L1
L2
L3
L1
L2
L3
Un
1 2 3
A1
A2
A2
A1
NC C NO
(0.5 A, 125 V AC)
MKC-03L
L1
L2
L3
L1 L2 L3
Sistem
N
MKC-04A
1 2 3
T1
M
3 ~
C1
T1
Stop
T1
N
M
3 ~
Start
L1
L2
L3
N
C1
L1 L2 L3
MKC-03A
1 2 3
N
T1
Stop
Start
C1
C1
T1
Stop
T1
N
M
3 ~
Start
L1
L2
L3
N
C1
3
2
1
N
L1
L2
L3
MKC-03A
1 2 3
L1 L2 L3
L1
L2
L3
System
N
T1
M
3 ~
MKC-04A
T1
Stop
Start
C1
V
Ref
V
Ref
= 380 VAC
x 100
asymmetry % =
-
V
L12
V
L31
V
L31
V
L12
V
L23
