SIEMENS
10/90
Siemens IC 10 · 2017
Relays
SIRIUS 3UG45, 3UG46 Monitoring Relays for Stand-Alone Installation
Power factor and active current monitoring
10
■
Overview
SIRIUS 3UG4641 monitoring relay
The 3UG4641 power factor and active current monitoring device
enables the load monitoring of motors.
Whereas power factor (p.f.) monitoring is used above all for
monitoring no-load operation, the active current monitoring
option can be used to observe and evaluate the load factor over
the entire torque range.
■
Benefits
•
Can be used worldwide thanks to wide voltage range from
90 to 690 V
(absolute limit values)
•
Monitoring of even small single-phase motors with a no-load
supply current below 0.5 A
•
Simple determination of threshold values by the direct
collection of measured variables on motor loading
•
Range monitoring and active current measurement enable
detection of cable breaks between control cabinets and
motors, as well as phase failures
• Cos
or
I
res
(active current) can be selected as the
measurement principle
•
Width 22.5 mm
•
All versions with removable terminals
■
Application
•
No-load monitoring and load shedding, such as in the event of
a V-belt tear
•
Underload monitoring in the low-end performance range,
e.g. in the event of pump no-load operation
•
Monitoring of overload, e.g. due to a dirty
filter system
•
Simple power factor monitoring in power systems for control of
compensation equipment
•
Broken cable between control cabinet and motor
■
Technical specifications
3UG4641 monitoring relays
The 3UG4641 monitoring relay is self-powered and serves the
single-phase monitoring of the power factor or performs over-
shoot, undershoot or range monitoring of the active current de-
pending on how it is parameterized. The load to be monitored is
connected upstream of the IN terminal. The load current flows
through the terminals IN and Ly/N. The setting range for the
power factor is 0.1 to 0.99 and for the active current
I
res
it is
0.2 to 10 A. If the control supply voltage is switched on and no
load current flows, the display will show
I
< 0.2 and a symbol for
overrange, underrange or range monitoring. If the motor is now
switched on and the current exceeds 0.2 A, the set ON-delay
time begins. During this time, if the set limit values are undershot
or exceeded, this does not lead to a relay reaction of the
changeover contact. If the operational flowing active current
and/or the power factor value falls below or exceeds the respec-
tive set threshold value, the spike delay begins. When this time
has expired, the relay changes its switch position. The relevant
measured variables for overshooting and undershooting in the
display flash. If monitoring for active current undershoot is
switched off (
I
res
▼
= OFF), and if the load current undershoots
the lower measuring range threshold (0.2 A), the CO contacts
remain unchanged. If a threshold value is set for the monitoring
of active current undershooting, then undershooting of the
measuring range threshold (0.2 A) will result in a response of the
CO contacts.
The relay operates either according to the open-circuit or
closed-circuit principle. If the device is set to Auto RESET
(Memory = No), depending on the set principle of operation, the
switching relay returns to its initial state and the flashing ends
when the hysteresis threshold is reached.
If Manual RESET is selected in the menu (Memory = Yes), the
switching relay remains in its current switching state and the
current measured value and the symbol for undershooting and
overshooting continue to flash, even when the measured vari-
able reaches a permissible value again. This stored fault status
can be reset by simultaneously pressing the UP
▲
and DOWN
▼
keys for 2 seconds, or by switching the supply voltage off and
back on again.
With the closed-circuit principle selected
Response in the event of undershooting the measuring range limit
•
With activated monitoring of
I
res
▼
•
With deactivated monitoring of active current undershooting
21/22
21/24
11/12
11/14
Lx-Ly/N
I
= 0,2 A
I
= 0
I
< 0,2 A
I
res
onDelay
onDelay
NSB0_01658b
< 0,2 A
onDelay
onDelay
NSB0_01917b
21/22
21/24
11/12
11/14
Lx-Ly/N
= 0,2 A
= 0
res
= off
© Siemens AG 2016