Specifications are subject to change without notice 1
Current and Voltage Controls
Product Description
AC plug-in current metering
relay. This relay is operating
with commonly available
standard current transformers,
..A/ 1A - .. A/5 A. Often used
• AC current control relay
• For AC standard current transformers
• Current measuring range: .. A/1 AAC or .. A/5 AAC
• Knob-adjustable current level
• Latching at set level possible
• Output: 10 A SPDT relay
• Plug-in type module
• S-housing
• LED-indication for output ON
• AC or DC power supply
Ordering Key
Housing
Function
Output
Type
Power supply
Measuring range
Type Selection
Plug Output Measuring ranges Supply: 24 VAC Supply: 115 VAC Supply: 230 VAC Supply: 24 VDC
Circ. SPDT 0.2 - 1 AAC SJ 175 024 1A SJ 175 115 1A SJ 175 230 1A SJ 175 724 1A
1 - 5 AAC SJ 175 024 5A SJ 175 115 5A SJ 175 230 5A SJ 175 724 5A
Input Specifications
Input
Pins 5 & 7 AC current
Measuring ranges
Types Ranges Internal
resist.
SJ 175 ... 1A 0.2 - 1 AAC 0.1 Ω
SJ 175 ... 5A 1 - 5 AAC 0.02 Ω
Max. overload current
1 A: 8 AAC (30 sec.)
5 A: 40 AAC (10 sec.)
25 AAC (30 sec.)
Latching Interconnect pins 8 & 9
latching at set level, no
latching at DC supply
Power supply AC types Overvoltage cat. III (IEC 60664)
Rated operational voltage (IEC 60038)
Through pins 2 & 10 024 24 VAC ± 15%, 45 to 65 Hz
115
115 VAC ± 15%, 45 to 65 Hz
230
230 VAC ± 15%, 45 to 65 Hz
Voltage interruption ≤40 ms
Dielectric voltage
2 kVAC (rms) (supply/elect.)
Rated impulse withstand volt. 4 kV (1.2/50 µs) (line/neutral,
line/line), no direct connec-
tion to electronics
Power supply DC types Overvoltage cat. III (IEC 60664)
Rated operational voltage (IEC 60038)
Through pins 2 & 10
724 24 VDC ± 15%
Dielectric voltage None (supply/elect.)
Rated impulse withstand volt. 800 V (1.2/50 µs)
Rated operational power
AC supply 2.5 VA
DC supply 1.5 W
to detect over and underlo-
ads. The relay features built-
in latch function which can
be used e.g. to hold an alarm
ON.
1-Phase AC Current Control
Type SJ 175
Supply Specifications
SJ 175 024 1A
2Specifications are subject to change without notice
SJ 175
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
≥2.0 kVAC (rms) (cont./elect.)
Rated impulse withstand volt. 4 kV (1.2/50 µs) (cont./elect.)
(IEC 60664)
Reaction time Relay operates: τ= 22 ms
Relay releases: τ= 2.2 s
worst case reaction time
may be up to 5 x τ
Accuracy 0 to +10% on max.
Min. actual level
≤set level
Indication for
Output ON LED, yellow
Environment (IEC 60947-1)
Degree of protection IP 20 B (IEC 60529)
Pollution degree 2 (IEC 60664)
Operating temperature -20° to +50°C (-4° to +122°F)
Storage temperature
-50° to +85°C (-58° to +185°F)
Weight AC supply 200 g
DC supply 125 g
Approvals UL, CSA
Mode of Operation
The SJ 175 measures the av-
erage of a sinusoidal current.
The set point, calibrated to
rms-value, is set on the built-
in potentiometer.
Example 1
AC current metering
The relay operates when the
measured current from the
standard through-primary
transformer exceeds set point.
The relay releases when the
current value drops 10% (see
hysteresis).
Example 2
AC current limiter
- latching
The diagram shows the relay
connected to standard
through-primary transformer
as a current limiter with latch-
ing.
The relay operates when the
measured current reaches set
point. Thus a contactor can
be activated either by inter-
rupting the primary current
wholly/partly, or by shortcir-
cuiting the input (pins 5 and 7)
of the relay.
The latching is reset when a
new measurement is required,
provided that the measuring
current is below set point less
hysteresis.
Note:
Internal connection between
pins 7 and 10 at DC power
supply. No current is to pass
through this internal connec-
tion.
Wiring Diagrams
Example 2
Power supply
SJ 175
Power supply
SJ 175
PE = Pin 7
Example 1
Latch
Output Specifications General Specifications
Specifications are subject to change without notice 3
SJ 175
Sockets◊S 411
Hold down spring◊HF
Mounting rack SM 13
Socket covers BB 4
Front mounting bezel FRS 2
Potentiometer lock PL 1
Through-primary current transformer, 1 or 5 A,
secondary output.
For further information refer to "Accessories".
Accessories
Range Setting
Range setting
Relay set point adjustable on
absolute scale.
Hysteresis
Approx. 10%.
The hysteresis may be extend-
ed to 75% by connecting a
resistor between pins 8 and
9. Resistor limits are 470 kΩ
and 3 kΩ(0.25 W). The hys-
teresis is increased by de-
creasing resistance.
Operation Diagrams
Example 1
Power supply
Set value
Input voltage from pins 5 & 7
Relay ON
Example 2
Power supply
Latching
Set value - 10%
Input voltage from pins 5 & 7
Relay ON
