MOTOR PROTECTION SWITCHES

MS25, MST25, MS20, MST20

• Versions:
- MS25 – with thermal and magnetic releases
- MST25 – with a thermal release
- MS20 - with thermal and magnetic releases for single-phase consumers
- MST20 – with a thermal overload release for single phase consumers
• Manual control:
- START, STOP, push-buttons
- Test of release function (TEST)
• Automatic switch-off with thermal or magnetic release
• Control with under-voltage release or shunt release
• An auxiliary switch for side mounting or flush mounting used for
indicating the switching state
• ON/OFF, push-buttons position unequivocally indicates the switching
position of main circuit contacts

• Contact material:
- Resistant to contact weld
- Enables low contact heating
• Isolating distance between contacts: 4.5 mm per contact place
• Connection of a rigid or flexible conductor
• Assembly to 35 mm wide mounting rail in accordance with EN 60715 or fixing with two screws
• Vertical or horizontal operation position

TECHNICAL DATA

Standards IEC/EN 60947-2, IEC/EN 60947-4-1, IEC/EN 60947-5-1,

IEC/EN 60204, UL 508, CSA 22.2 No. 14
Approvals UL, SEMKO
Climatic class constant damp heat acc. to IEC 60068-2-78
cyclic damp heat acc. to IEC 60068-2-30
Degree of protection IP20, after terminals covering IP20
Ambient temperature °C -25 … +60
GENERAL

Storage temperature °C -25 … +70

Temperature range of thermal compensation for
°C -5 … +40
overload release
Mechanical and electrical endurance op. c. 100,000
Shock resistance acc. to IEC 68-2-27 g 20
Vibration resistance acc. to IEC 68-2-6 5 g at f = 5 … 150 Hz
Overvoltage category / pollution degree III / 3
Rated insulation voltage Ui V 690
Rated impulse withstand voltage Uimp kV 6
Weight kg 0.252

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 MOTOR PROTECTION SWITCHES

MS25, MST25, MS20, MST20

TECHNICAL DATA

Designation of connection 1 − L1 ; 3 − L2 ; 5 − L3 ; 2 − T1 ; 4 − T2 ; 6 − T3
terminals
Terminal capacity rigid 0.75 … 6
S mm2
flexible 0.75 … 4
with self-lifting clamp,
Screw
protected against falling out
Screw head PZ2

Tightening torque Nm 1.8

Max. operational voltage Ue V 690

MAIN CIRCUIT

Setting range 0.1 − 0.16 (only MS25); 0.16 − 0.25 (only MS25);
0.25 − 0.4; 0.4 − 0.63; 0.63 − 1; 1 − 1.6; 1.6 − 2.5; 2.5 − 4;
A
4 − 6.3; 6.3 − 10;
10 − 16; 16 − 20; 20 - 25
No. of poles 3
Operating current of thermal 1.05 Ir < I b 1.20 Ir
I
overload release Ir….set value

Sensitivity to phase failure yes

Operating current of magnetic 11 In< I b 13 In ± 20 %
I
overload release In…upper setting limit

Power dissipation on pole at load 2 − 2.5

P W
with In
Utilization category acc. to IEC/EN 60947-4-1 AC-3
acc. to IEC/EN 60947-2 A
Trip class acc. to IEC/EN 60947-4-1 10A

SWITCH SELECTION FOR MOTOR PROTECTION

Standard motor power Setting range

Single-phase Three-phase
220 V 220 V 380 V 440 V 500 V 660 V
230 V 230 V 400 V 690 V
240 V 240 V 415 V
kW A
0.02 0.06 0.1 … 0.16
0.06 0.06 0.06 0.09 0.16 … 0.25
0.06 0.09 0.12 0.12 0.18 0.25 … 0.4
0.09 0.12 0.18 0.25 0.25 0.4 … 0.63
0.06 … 0.09 0.09 … 0.12 0.18 … 0.25 0.25 0.37 0.37 … 0.55 0.63 … 1
0.12 0.18 … 0.25 0.37 … 0.55 0.37 … 0.55 0.55 … 0.8 0.75 … 1.1 1 … 1.6
0.18 … 0.25 0.37 0.75 … 1.1 0.75 … 1.1 1.1 1.5 1.6 … 2.5
0.37 0.55 … 0.8 1.1 … 1.5 1.5 1.5 … 2.2 2.2 … 3 2.5 … 4
0.55 … 0.75 1.1 … 1.5 2.2 … 2.5 2.2 … 3 3 4 4 … 6.3
1.1 … 1.5 1.5 … 2.5 3…4 4…5 4 … 5.5 5.5 … 7.5 6.3 … 10
2.2 3…4 5 … 7.5 5.5 … 9 7.5 … 9 11 10 … 16
3 5.5 9 11 11 … 12.5 15 16 … 20

'! 5.5 … 7.5 11 … 12.5 12.5 15 18.5 20 … 25

 MOTOR PROTECTION SWITCHES

MS25, MST25, MS20, MST20

MS25 motor protection switches, rated ultimate short-circuit breaking capacity Icu and max. back-up fuses if
prospective short-circuit current Icp exceeds Icu:

Type Operating Rated ultimate short-circuit breaking capacity Icu

Max. back-up fuse, if Icp > Icu
current of (kA)
short-circuit (gL) (A)
release
(A) 230 V 400 V 500 V 690 V 230 V 400 V 500 V 690 V
Icu Icu Icu Icu

MS25 − 0.16 2 50 50 50 50
MS25 − 0.25 3 50 50 50 50
MS25 − 0.4 5 50 50 50 50
No back-up fuse required
MS25 − 0.63 8 50 50 50 50
MS25 − 1 12 50 50 50 50
MS25 − 1.6 20 50 50 50 50
MS25 − 2.5 33 50 50 3 2.5 25 20
MS25 − 4 44 50 50 3 2.5 35 25
MS25 − 6.3 75 50 50 3 2.5 50 35
MS25 − 10 120 50 6 3 2.5 80 50 35
MS25 − 16 160 6 4 2.5 2 80 80 63 35
MS25 − 20 230 6 4 2.5 2 80 80 63 50
MS25 − 25 270 6 4 2.5 2 80 80 63 50

MST25 motor protection switches and max. back-up fuses for short-circuit protection:

Type Max. back-up fuse

Ue <400 V gL (A)

MS25 − 0.4 1
MS25 − 0.63 2
MS25 − 1 2
MS25 − 1.6 4
MS25 − 2.5 6
MS25 − 4 16
MS25 − 6.3 20
MS25 − 10 25
MS25 − 16 35
MS25 − 20 50
MS25 − 25 50

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 MOTOR PROTECTION SWITCHES

MS25, MST25, MS20, MST20

ACCESSORIES

Auxiliary switch for lateral Rated insulation voltage Ui V 500

mounting PS Thermal current Ith A 6
PS 11 – with one make and one break 230 V 3.5
contact Rated operational current
PS 10 – with one make contact 400 V Ie A 2
at AC-15
PS 01 – with one break contact 500 V 1.5
PS 20 – with two make contacts
Terminal capacity S mm2 0.75 … 2.5
Tightening torque Nm 1

Under-voltage release U
Control voltages Uc V 24 … 600
Shunt release A
Rated frequency f Hz 50 or 60

Rated insulation voltage Ui V 500

Trip-indieating auxiliary switch Thermal current Ith A 6

RS and 230 V 3.5

Rated operational
auxiliary flush-type switch PS
RS

400 V Ie A 2
current at AC-15
RS 10 – with one make contact 500 V 1.5
RS 01 – with one break contact
Rated 230 V 3.5
PSV11 – with one make and one break
RSV

operational
contact 400 V Ie A 2
current at
AC-15 500 V 1.5
Terminal capacity S mm2 0.75 … 2.5
Tightening torque Nm 1

ENCLOSURES

O-41/55 CP-41/55
Enclosure IP41/55
MS25 or MST25 with all accessories
O-41/55
can be built into an enclosure or a
Front plate IP41/55
front plate.
CP-41/55

Emergency stop push-button NAT. It is also available with a key-lock.

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 MOTOR PROTECTION SWITCHES

MS25, MST25, MS20, MST20

Padlocking feature Z

The manufacturer also supplies an enclosure

and a front plate with degree of protection IP55
(O-55, CP-55); in this case the diaphragm is
Push-button diaphragm M
already mounted. However, it should be
removed if a padlocking feature or an
emergency stop bush-button is built-in.

One N/PE neutral link is usually built in the

Neutral link NL enclosure 0-41/55 or CP-41/55. A place for
an additional neutral link is also available.

230, 240, 400 V

Signal lamp SS…
B-white, R-red, Z-green

Connection diagram
1-pole 2-pole 3-pole

DIMENSIONS

MS25,
MST25, O-41/55 CP-41/55
MS20, MST20
ORDERING DATA
MS25 with the setting range 2.5 – 4.0 A:
MS25 - 4
The same switch with under-voltage release for control voltage 380 V with an auxiliary switch with two NO
contacts, built in the enclosure, with an emergency stop push-button and a green signal lamp for 230 V: '$
MS 25 – 4 / U 380 / PS 20 / 0-41 / NAT / SSz 230