Current and Voltage Controls
3 Phase-neutral Max. and Min. Voltage Control
Types S 1721, SYY 155
鈥?Monitoring relay for 3-phase upper/lower
phase-phase neutral voltage control
鈥?Measures if all 3 phase-neutral voltages are
within set limits
鈥?Measures on own power supply
鈥?Operates irrespective of phase sequence
鈥?Upper and lower limits separately adjustable
鈥?Built-in adjustable timer function
鈥?Output: 10 A SPDT relay
鈥?Plug-in type module
鈥?S-housing
鈥?LED-indication for power supply and output ON
鈥?Power supply is the 3-phase + N measuring voltage
Product Description
3-phase and neutral moni-
toring plug-in relay for sepa-
rate upper and lower voltage
control. Often used to control
all 3 phases and neutral where
the supplied electrical power
is unstable or varies in value
in order to monitor that the
attached motors are perfor-
ming as required. The S 1721
features built-in time delay.
Ordering Key
Housing
Type
Output
Power supply
S 1721 156 220
Type Selection
Plug
Circular
Circular
Output
SPDT
SPDT
Timer
Yes
No
Supply: 220 VAC
S 1721 156 220
SYY 155 220
Supply: 380 VAC
S 1721 156 380
SYY 155 380
Supply: 400 VAC
S 1721 156 400
Supply: 415 VAC
S 1721 156 415
SYY 155 415
Input Specifications
Input
Pins 5, 6 & 7
Pin 11
Measuring ranges
(VAC)
Power supply (phase-phase)
Range (phase-neutral)
Upper level
Scale
Lower level
Scale
Power supply (phase-phase)
Range (phase-neutral)
Upper level
Scale
Lower level
Scale
Arbitrary phase sequence
Neutral
3x220 +N
鹵 18%
104-150
130-150
102-118%
104-124
82-98%
3x380 +N 3x400+N
鹵 18% 鹵 18%
180-260 188-271
225-260 235-271
102-118% 102-118%
180-215 188-225
82-98% 82-98%
Output Specifications
Output
Rated insulation voltage
Contact ratings
(AgCdO)
Resistive loads
AC 1
DC 1
or
Small inductive loads AC 15
DC 13
Mechanical life
Electrical life
AC 1
Operating frequency
Dielectric strength
Dielectric voltage
Rated impulse withstand volt.
SPDT relay
250 VAC (rms)
(cont./elect.)
碌 (micro gap)
10 A/250 VAC (2500 VA)
1 A/250 VDC (250 W)
10 A/25 VDC (250 W)
2.5 A/230 VAC
5 A/24 VDC
鈮?/div>
30 x 10
6
operations
鈮?/div>
2.5 x 10
5
operations
(at max. load)
鈮?/div>
7200 operations/h
鈮?/div>
2 kVAC (rms) (cont./elect.)
4 kV (1.2/50 碌s) (cont./elect.)
(IEC 60664)
3x415+N
鹵 18%
204-276
252-276
102-118%
204-228
82-98%
measures value of own
supply. Range equals rms
value of a sinusoidal voltage
Specifications are subject to change without notice (26.10.99)
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