Rittal SK 3120.200 Notice D'emploi page 5

1 Application
Contents
EN
1. Application
2. Assembly
3. Functional description
3.1 Speed control
3.2 Minimum speed
3.3 Monitoring / malfunctions
3.4 LEDs
3.5 Remote sensor
4. Connection
5. Technical specifications
6. Safety instructions
7. Supply includes
8. Guarantee
1 Application
The SK 3120.200 is an electronic speed control
for 2-pole single-phase AC motors which may be
fitted independently.
This device may only be installed in an enclosure.
The speed control reduces the internal tempera-
ture of the enclosure to the set temperature. By
using this device, a significant reduction in fan
noise can be achieved. The fan speed is con-
trolled in a way which cools the enclosure
(assuming there is a supply of cold intake air).
This in turn leads to a reduced energy require-
ment. The speed control is particularly well-suited
to Rittal fan-and- filter units and air/air heat
exchangers.
2 Assembly
The device is simply snap-mounted onto the
35 mm support rail (EN 50 022).
3 Functional description
3.1 Speed control (P1)
The enclosure temperature is reduced to the
temperature set on the potentiometer P1 (assum-
ing a supply of cold intake air). The temperature
is measured via the remote sensor.
Upon reaching the set value, the fan operates at
a speed of 100 % (see diagram). Within the pro-
portional range of 10 K, speed control is linear. If
the temperature drops, the fan is deactivated at
13 K below the set value. The fan cuts back in at
10 K below the set value. When the fan is
switched on, it is activated with a start-up pulse.
6
3.2 Minimum speed (P2)
Upon reaching the minimum speed, the fan will
cut out. The setting is made as a percentage of
the maximum speed. It is important to ensure
that the fan still operates safely at the minimum
speed (refer to manufacturer's instructions in the
case of third-party fans).
With our fan-and-filter units from series
SK 3321.xxx − SK 3327.xxx, we recommend a
minimum speed of approximately 40 %.
Setting:
Set P2 to 100 %, P1 to 55 °C
Reduce P1 until the fan starts running
Set P2 to the required minimum speed
P1 can now be set to the required temperature.
Note: If the minimum speed = 100 %, the fan will
always run at maximum speed (no control).
3.3 Monitoring / malfunctions
In normal operation, contact 5-4 of the alarm
relay is open.
Overtemperature:
At a measured temperature of more than 10 K
above the set value, temperature monitoring will
cut in – see diagram.
The red LED will flash once.
The fault signal relay will drop out (terminal
5-4 closed).
Interruption in the cable to the fan:
The red LED will flash twice.
The fault signal relay will drop out (terminal
5-4 closed).
Sensor failure / short-circuit:
In this case, the fan is operating at full speed.
The red LED will flash three times.
The fault signal relay will drop out (terminal
5-4 closed).
Voltage failure
(controller de-energised):
The fault signal relay will drop out (terminal
5-4 closed).
3.4 LEDs
Green = operating voltage present
Red = malfunction, see 3.3