478 / 582
BETA Monitoring
Monitoring of Electrical Values
5
TT3 insulation monitors
for industrial applications
13/22
Siemens ET B1 · 10/2008
13
■
Overview
Insulation monitors are used for the protection of persons
against ungrounded systems – IT systems. The insulation
resistance of the system being monitored is measured against
ground.
These types of measurements are specified according to
DIN/VDE 0100-410 – Erection of power installations up to
1000
V – Protection against electric shock.
■
Benefits
•
The insulation monitoring for AC voltage systems of up to
500
V AC and 1000 Hz enables application in 400 V three-phase
systems
•
Easy operation with potentiometers as the set limit value of the
insulation resistance is always visible
•
Simple and cost-efficient solution for remote signaling and sig-
naling due to option for connecting an external LED and/or ex-
ternal testing and canceling pushbutton
•
Simplified planning and logistics as no auxiliary voltage is
required for the insulation monitoring of direct voltage systems
up to 280 V DC.
■
Technical specifications
5
TT3 470
5
TT3 471
Rated control voltage U
c
V AC 220 ... 240
--
V DC --
12 ... 280
Operating range
For AC supply
× U
c
0.8 ... 1.1
--
For DC supply
--
0.9 ... 1.25
Frequency range for U
c
Hz
45 ... 400
--
Rated power dissipation P
v
For AC supply
VA Approx. 2
--
For DC supply
W --
Approx. 1
Rated impulse withstand voltage U
imp
Terminals A1 to A2
kV
< 4
< 4
Terminals L to PE
kV
< 4
< 4
Terminals A1, A2 to L, PE
kV
< 4
< 3
Terminals against contacts
kV
< 6
< 6
Measuring circuit
For AC systems
For DC systems
Measurement voltage range U
meas
V AC 0 ... 500
--
V DC --
12 ... 280
Operating range
× U
meas
0 ... 1.1
0.9 ... 1.1
Frequency range for U
meas
Hz
10 ... 1000
--
Alarm values
Measuring shunt R
AL
k
5 ... 10
5 ... 200
Setting of alarm value
On absolute scale
Infinitely variable
Infinitely variable
Alternating current internal resistance
Internal testing resistor
k
> 250
--
Direct current internal resistance
Internal testing resistor
k
> 250
--
L+ and L- to PE
k
--
75
each
Measurement voltage U
meas
Internal
V DC Approx. 15
--
Max. measurement current
I
meas
Short circuit
mA < 0.1
0.2 ... 4,
depending on the voltage
Direct interference voltage
Max. permissible
V DC 500
--
Response delay
At R
AL
50
k and 1 F
and up to 0.9 x R
meas
s
< 1.3
0.8
and R
meas
from
to 0
s
< 0.7
0.4
Switching hysteresis
At R
meas
50
k
% 15
10 15
Contacts
contact
2
CO
2
CO
Rated operational voltage U
e
V AC 250
250
Rated operational current
I
s
Thermal current limit
I
th
A
4
4
AC-13 at 24 V DC
A
--
3
AC-13 at 250 V DC
A
--
0.2
AC-15
A
--
3
AC-15 NO contacts
A
5
--
AC-15 NC contacts
A
2
--
Terminals
±
screw (Pozidriv)
2
2
Conductor cross-sections
Rigid, max.
mm
2
2
× 2.5
Flexible, with end sleeve, min.
mm
2
1
× 0.50
Permissible ambient temperature
°C -20 ... +60
Degree of protection
EN 60529
°C IP20, with connected conductors
Resistance to climate
Acc. to EN 60068-1
20/060/04
© Siemens AG 2008