Specifications are subject to change without notice (26.10.99) 1
Current and Voltage Controls
• Mains network quality and load monitoring
relay
• Monitors phase sequence, phase loss,
phase asymmetry and phase angle
• Measures asymmetry on 3-ph. voltage without neutral
• Built-in adjustable timer function
• Knob-adjustable asymmetry sensitivity
• Output: 10 A SPDT relay
• Plug-in type module
• S-housing
• LED-indication for power supply and output ON
• Power supply is the 3-phased measuring voltage
Product Description
3-phase plug-in monitoring
relay for phase sequence,
phase loss, phase asymme-
try and phase angle. Fre-
Ordering Key
Housing
Type
Output
Power supply
Frequency
Product Selection
Plug Output Timer Frequency Supply: 220 VAC Supply: 380 VAC Supply: 400 VAC Supply: 415 VAC
Circ. SPDT Yes 50 Hz S 171 156 220-50 S 171 156 380-50 S 171 156 400-50 S 171 156 415-50
Yes 60 Hz S 171 156 220-60 S 171 156 380-60 S 171 156 400-60 S 171 156 415-60
Circ. SPDT No 50 Hz SY 175 220-50 SY 175 380-50 SY 175 415-50
No 60 Hz SY 175 220-60 SY 175 380-60 SY 175 415-60
Input Specifications
Input
Pin 5 Phase L1
Pin 6 Phase L2
Pin 7 Phase L3
measures on own supply
Output SPDT relay
Rated insulation voltage 250 VAC (rms)
(cont./elect.)
Contact ratings (AgCdO) µ (micro gap)
Resistive loads AC 1 10 A/250 VAC (2500 VA)
DC 1 1 A/250 VDC (250 W)
or 10 A/25 VDC (250 W)
Small inductive loads AC 15 2.5 A/230 VAC
DC 13 5 A/24 VDC
Mechanical life ≥30 x 106operations
Electrical life AC 1 ≥2.5 x 105operations
(at max. load)
Operating frequency ≤7200 operations/h
Dielectric strength
Dielectric voltage ≥2 kVAC (rms) (cont./elect.)
Rated impulse withstand volt. 4 kV (1.2/50 µs) (cont./elect.)
(IEC 60664)
Power supply AC types Overvoltage cat. III (IEC 60664)
Rated operational voltage (IEC 60038)
through pins 5, 6 & 7 220 3 x 220 VAC ± 15%,
50 or 60 Hz
380 3 x 380 VAC ± 15%,
50 or 60 Hz
400 3 x 400 VAC ± 15%,
50 or 60 Hz
415 3 x 415 VAC ± 15%,
50 or 60 Hz
Voltage interruption ≤40 ms
Dielectric voltage None (supply/elect.)
Rated impulse withstand volt. 4 kV (1.2/50 µs) (line/neutral,
line/line), direct connection
to electronics
Rated operational power 3 VA
quently used to control the
mains in electrical distribu-
tion systems. The S 171 mod-
ule features built-in time delay.
3-Phase Asymmetrical Control
Types S 171, SY 175
Output Specifications
Supply Specifications
S 171 156 220-50
2Specifications are subject to change without notice (26.10.99)
S 171, SY 175
Reaction time
τ= 0.2 s, worst case reaction
time may be up to 5 x τ
Adjustable delay on release
built-in (0.2s - 10s)
Note:
Reaction time + set time =
actual delay on release time
Accuracy
OFF delay 10 s, -1/+3 s on max.
< 0,1 s on min.
Time function (S 171)
Delay on release 0.2-10 s. adj.
Indication for
Power supply ON LED, green
Output ON LED, red
Environment (IEC 60947-1)
Degree of protection IP 20 B (IEC 60529)
Pollution degree (IEC 60664)
1: S 171 380/400/415
SY 175 380/415
2: S 171 220, SY 175 220
Operating temperature -20° to +50°C (-4° to +122°F)
Storage temperature -50° to +85°C (-58° to +185°F)
Weight 200 g
Approvals S 171: UL, CSA, SEV
(SEV only 3 x 220 VAC)
SY 175: UL, CSA
The knob-adjustable relays
detect phase asymmetries of
2 to 12% of phase-phase
amplitude.
The relay operates when all
three phases are present at
the same time and the phase
sequence is correct as well as
the measured asymmetry/un-
balance is below set point (2
to 12% of phase asymmetry).
Phase angle failures are regi-
stered as phase asymmetry.
S 171 releases if one or more
of the above factors deviate
for more than the set time. SY
175 releases immediately.
If the supply voltage drops to
approx. 25% of the phase-
phase voltage, the relay re-
leases without time delay.
Mode of Operation
Applications of asymmetry
I: Mains monitoring:
Phase sequence.
Phase loss.
Phase amplitude
asymmetry.
II: Load monitoring:
Phase sequence (direction
of motor rotation).
Fuse blowing.
Example 1
Mains network monitoring
The relay monitors phase
loss, that the power supply
has correct phase sequence,
that all three phases are
present, and that the phase
asymmetry is within the pre-
set level.
Setting
The allowed asymmetry for
the mains voltage amplitudes
is set on the potentiometer.
Example 2
Starting and operating load
monitoring
The 3-phased monitoring re-
lays for electrical loads en-
sure correct starting and op-
erating conditions. The relays
measure phase sequence and
consequently the correct di-
rection of motor rotation.
The most frequent cause of
asymmetry and unbalance is
fuse blowing. In this case the
motor regenerates the inter-
rupted phase. The size of the
regenerated phase depends
on the actual me- chanical
load and motor size. In this
case it is a combination of
phase amplitude and phase
angle asymmetry, and nor-
mally the regenerated voltage
will cause an asymmetry
higher than 2-3%.
Setting
Turn the asymmetry potentio-
meter counterclockwise (from
max.) until the relay releases.
Continue turning approx. 1
mark clockwise to ensure cor-
rect operation. At approx. 5%
or less asymmetry, ensure that
possible power supply varia-
tions do not result in errone-
ous releases.
Example:
Usupply nom. = 380 VAC
Setpoint = 6% ~ 23 VAC
Hysteresis = 1% ~ 4 VAC
The relay is ON if all 3 phase-
phase voltages are within the
range of 357 to 403 VAC. The
relay is OFF if one or several
phase-phase voltages are
higher than 403 VAC plus 1%
= 410 VAC or lower than 357
less 1% = 349 VAC.
Wiring Diagrams
Example 1 Example 2
General Specifications
Specifications are subject to change without notice (26.10.99) 3
S 171, SY 175
SY 175
Phase L1, pin 5
Phase L2, pin 6
Phase L3, pin 7
Set asymmetry
Hysteresis
Measured asymmetry
Relay ON
Sockets◊S 411
Hold down spring◊HF
Mounting rack SM 13
Socket covers BB 4
Front mounting bezel FRS 2
Potentiometer lock PL 2
For further information refer to "Accessories".
AccessoriesTime/Range Setting
Range setting
Lower potentiometer:
Phase asymmetry sensitivity
2% (± 1,7%) to 12% (+4,5%,
-0,5%) of phase-phase am-
plitude. Adjustable on abso-
lute scale.
Hysteresis:
≤2% of nominal voltage.
Time setting
Upper potentiometer
(not SY 175):
Time
Adjustable time delay on re-
lease: 0.2 to 10s
Time setting on relative scale.
Operation Diagrams
S 171
Phase L1, pin 5
Phase L2, pin 6
Phase L3, pin 7
Set asymmetry
Hysteresis
Measured asymmetry
Relay ON
