Control

Typee of application

Typee of application Typee of control cabinet
1 st Termonic
-10…+95°C
2 st Termonic
-10…+95°C
3 st Termonic
-10…+95°C
4 st Termonic
-10…+95°C
De-icing regulator Roof thermostat
Double sensors
Set point Frost protection
Max power 2 kW Type 01
Max power 6 kW Type 11
Max power 12 kW Type 21 Type 22
Max power 18 kW Type 31p Type 32p Type 33p
Max power 24 kW Type 41p Type 42p Type 43p Type 44p
Floor heating/Industrial heating
Max power 2 kW Type 01
Max power 6 kW Type 11
Max power 12 kW Type 21 Type 22
Max power 18 kW Type 31p Type 32p Type 33p
Max power 24 kW Type 41p Type 42p Type 43p Type 44p
Surface heating/Melting of snow
Max power 2 kW Type 01
Max power 6 kW Type 11 Type 11mm* Typec 11 IC
Max power 12 kW Type 21 Type 22mm* Type 21 ICp
Max power 18 kW Type 31p Type 32mm*p Type 33p Type 31 ICp
Max power 24 kW Type 41p Type 42mm*p Type 43p Type 44p Type 41ICp
Frost protection of gutters and down pipes
Max power 2 kW Type 01-tak
Max power 6 kW Type 11 Tak IC Type 11-tak
Max power 12 kW Type 21 Tak IC Type 21-tak
Max power 18 kW Type 31 Tak IC Type 31-takp
Max power 24 kW Type 41 Tak IC Type 41-takp

Three-phase group

THE CONSTRUCTION OF THE THREE-PHASE GROUP

All standard design Värmekabelteknik control cabinets are factory assembled with complete three-phase groups made up of:

  • Siemens earth-leakage-circuit breaker (ELCB) (One four-pole breaker per three-phase group)
  • Siemens circuit-breakers ( three circuit breakers per three-phase group)
  • Siemens 4x20A contactor (One contactor per three-phase group)
  • Värmekabelteknik:s LED indicator module containing current transformers

Main switch

Each control cabinet contains a main switch Siemens adapted to the maximum load rating of the cabinet.

Control group construction

The control group consists of a Siemens control switch, a Siemens 6A circuit-breaker and a control unit.

To avoid overloading the electricity supply system after a mains failure, the larger control cabinets 31-41 also have a time delay relay for delayed operation.

Control applications

Floor heating, pipe tracing, vessel tracing and other applications: The Termonic DIN bus bar thermostat with a thermostat sensor registering the existing temperature of the installation, hysteresis being adjustable.

Roof application: The OJ Double thermostat for sensing roof and ambient temperatures, permitting operating conditions that make for a relatively low power consumption and an installation that functions well.

Function: The thermostat relay operates when the roof sensor detects above-zero temperatures (melting) and the wall sensor detects below-zero temperatures (risk of freezing of gutters, down pipes and drainpipes).
Roof application: Eismelder snow melting regulator with twin sensors, one for temperature monitoring, the other for moisture detection. This is an attractive alternative for high-output installations requiring low operation costs.

Function: This type of control is very exact, as switching on only takes place when there is moisture on the moisture sensor (mounted in gutter or moulding) and the temperature sensor at the same time detects a risk of freezing of gutters, down pipes or drainpipes.

Snow and ice melting ground installations: Here, high-output systems (typically 300 W/m²) are required: The Eismelder snow melting regulator with ground sensors (moisture and temperature sensors and a heated ice and snow sensor) which can be used for all types of ground surfaces, including those carrying heavy vehicles. The sensors are embedded in the surface, level with it, and monitor for the surface temperature and all types of precipitation.

Function: The system’s relay operates when moisture or precipitation is detected on the surface to be protected, and there is at the same time a risk of freezing. There is also a built-in time-delay relay to compensate for any variations in the surface. This configuration will minimize operating costs and maximize performance.

Special control cabinets

Control cabinets with different types of regulators are also available, from single-channel on/off regulators to 10-channel multiloop regulators with connections for remote control via PC via a two-wire or telephone and modem connection.

We design, construct and build cabinets of all sizes to customer specifications. One example would be the control cabinets we have delivered for controlling ground areas, bridges, stairways and steps at the Globe in Stockholm, where the cabinets are connected to the DUC (a computer sub-centre) for overall control functions. Another, the control cabinets containing 50-75 three-phase groups for electrically heated car test courses in the interior of Norrland (Northern Sweden). That particular high-power installation required several hundred kilowatts.

For Värmekabelteknik, no control cabinet is too small or too big to make, and no customer requirement too tough to meet!

Fuses

FUSE OPTIONS

Circuit-breakers have many advantages over diazed fuses, but these advantages sometimes turn into disadvantages.

The instantaneous trip of a circuit-breaker when there is a short-circuit makes it necessary to take into account the starting currents in self-limiting cables and provide for a wide margin in order to prevent the circuit-breaker from tripping spontaneously when such an installation is being started in low ambient temperatures. A G-characteristic fuse-link is also applied here, which is extra slow so that for the cables connecting cabinet and heating cables large conductor areas are unnecessary.

A further circuit-breaker drawback to keep in mind is that the continuous load current should not be greater than 80 per cent of rated current (for example, 0.8 x 10A = 8A).

Lockable main switch

A control cabinet that is to be mounted in a space (such as the electric-power room or niche) where access is not restricted by a separate locked door, will be furnished with a lockable main switch if you request this when ordering the cabinet.

Enclosure classes

The control cabinet enclosure is made of polystyrol and has a transparent polycarbonate cover. Enclosure class IP55.

The control cabinet enclosure is constructed of enamelled sheet steel. Glazed door and cylinder lock available on request. Enclosure class IP55 (IP65 possible with special accessories).

Connections

The Värmekabelteknik control cabinets are designed for connection to a five-conductor system. (Other connection types are available on request).

Each outgoing terminal-block group consists of an earth-terminal block, a neutral terminal-block, and three terminal-blocks for L1-L3.

The control cabinets are supplied containing sensors with the sensor wire connected to the designated terminal blocks, except for the IC ground cabinets where the sensors are supplied unconnected.