TYPES 11-21-31-41 MAX-MIN CONTROL CABINETS: MODE OF OPERATION
Control cabinet 11 is intended for max. 3 x 2300W three-phase heating-cable installation
Control cabinet 21 is intended for max. 6 x 2300W
Control cabinet 31 is intended for max. 9 x 2300W
Control cabinet 41 is intended for max. 12 x 2300W
This control cabinet is designed for heating cable applications on pipes, containers and tanks, underground and in floors and the like, all with thermostat control.
This cabinet may be designed to special order for loads exceeding 10A per phase.
|Main switch 3-pole
|Control switch, manual-0-automatic
|Thermostat Termonic 26090 incl. 2 sensors
|Contactor(s), 4 x 20A
|ELCB(s), 4-Pole 25/0,03A
|Operating status indicator(s) for three-phases
This control cabinet is intended for wall mounting and cable entry is via all sides.
The cabinet controls the temperature of a surface, keeping it to the value preset on T2. Heating is switched off if ambient air temperature falls below the value preset on T2.
Putting into service
- Using a screwdriver, set the operation thermostat T2 adjustment knob for the required operating temperature (the temperature range may have to be adjusted.
- Using a screwdriver, set the air thermostat T1 temperature adjustment knob for the required release temperature (the temperature range may have to be adjusted).
- Put the ELCB toggle switch in the ON position.
- Turn the main switch to the ON position.
- When the current has been switched on, the sensor LEDs light up indicating status, as explained below.
Red LED lighting up: sensor fault or temperature range incorrectly set.
Yellow LED lighting up: thermostat operating (sensor temperature below preset value)
Hysteresis (number of degrees between thermostat switching on and thermostat switching off) must be adjusted in such a way that the thermostat meets the temperature-control accuracy requirements.
It should be noted that the service life of the thermostat relay will be shorter if settings are used which produce low hysteresis in cases of fast processing.
If the thermostat and/or succeeding contactors should rattle on release, then hysteresis should be somewhat increased.
Change of temperature range in order to avoid end positions. An incorrect temperature range may lead to a sensor malfunction being indicated.
Connection of the cabinet is made to a 5-conductor system.
The 5 x 1,5 mm² supply cable (maximum 5 x 4mm²) is connected to the main switch of the cabinet and to the neutral and earth terminal blocks.
The heating coils are connected directly to the cabinet’s earth terminal block (G-G), to the neutral terminal block (terminal block 1), and to the outgoing phases L1 (terminal block 2), L2 (terminal block 3) and L3 (terminal block 4), alternatively to 5×1,5mm² or to 3 x 3 x 1,5mm² for further connecting to a junction or junction boxes.
The T1 sensor should be mounted in, for example, conduit or in a junction box on a wall facing north. The T2 sensor should be mounted in conduit between cable turns.
The sensor lead (integral, 3m) may be jointed up to a length of 50m without affecting temperature adjustment knob accuracy. The sensor is connected to terminal block 117, 118 using 2 x 1,5 mm².