EU declaration conformity
AC fan speed controller 400 V | overload protection | 4 A
Product description
This is a five-step fan speed controller with a thermomagnetic circuit breaker built in. It controls three-phase 400 volt motors. The maximum combined motor current is 4 A.
The rotary switch is used to control the fan speed. Remote start/stop orders can be sent via the digital input. After a power outage, the motor will resume automatically. The thermomagnetic circuit breaker will promptly trip and stop the motor in the event of a short circuit or overload.
By lowering the motor voltage with autotransformers, the fan speed is controlled in five stages. The output voltage's precise sinusoidal form ensures that the motor runs quietly.
In interior conditions (IP54), the metal casing enables for surface mounting.
The power source voltage is 400 VAC.
Documents
Additional specifications and description
One of the five available speeds can be selected via the rotary switch. At position 0, the motor is disabled. Position 1 is the lowest speed and position 5 is highest speed.
Remote start-stop
Via the input(s), the motor can be remotely enabled or disabled. There are a normally open input and a normally closed input available.
This means that using a remote switch - connected to the normally open input - the motor can be enabled or disabled. A smoke alarm can be connected to the normally closed input. In the event of smoke alarm occurrence, the motor will be disabled, regardless of the status of the other input.
Unregulated output
The extra, unregulated output (230 VAC) is active when the motor is enabled. It can be used to control an external operation indicator, a damper, etc. When the fan is deactivated, the damper is closed and when the fan is active, the damper is open.
Thermal motor protection
This fan speed controller can monitor thermal motor contacts (TK or thermal contacts measure temperature in the motor windings). In case of motor overheating, the TK monitoring function will disable the motor to prevent motor damage. If the motor is not equipped with TK contacts, the TK terminals of the controller must be bridged to simulate normal motor temperature.
Built-in thermomagnetic circuit breaker
A thermal-magnetic circuit breaker, is a type of electrical protection device designed to interrupt the flow of electrical current in a circuit under certain conditions. It combines two types of protection mechanisms: thermal and magnetic.
The thermal component of the breaker responds to overcurrent conditions that persist for an extended period. When the current flowing through the circuit exceeds the rated capacity, the heat generated causes a bimetallic strip to bend. This bending action triggers the tripping mechanism, opening the circuit and interrupting the current flow. This protection is effective against sustained overloads.
The magnetic component responds to short-circuit currents, which are characterized by a rapid and intense increase in current. In the presence of a short circuit, the magnetic field generated by the high current causes a magnetic trip to occur, rapidly opening the circuit and disconnecting the power supply. This protection mechanism acts quickly to address sudden and severe overcurrent events
In case of a short circuit or overload, the thermomagnetic circuit breaker will immediately trip and deactivate the motor.
Alarm output
The alarm output (230 VAC) is activated when motor problems occur. It can be used to generate alerts. For instance, in case of motor overheating, the alarm output is activated. The TK monitoring function will disable the motor to prevent further damage. The alarm output can control a warning light.
Auto reset after power failure
In the event of a power failure, the STTA4 fan speed controller incorporates an auto-reset feature. This means that once power is restored, the controller will automatically reset itself. As a result, the connected motor will restart automatically without requiring manual intervention.
Solid metal enclosure
Sentera pays close attention to the quality of both the electrical and non-electrical aspects of the produced and supplied products. The enclosure of the STTA4 controller is made of sheet steel with a protective coating, providing reliable protection against mechanical and other influences. It is certified according to the European standard EN 62208 and has an IP54 dust and water protection rating.
To ensure maximum reliability and safe operation, as well as to prevent overheating, the controller should be installed in a cool place away from direct sunlight. The ambient temperature for the operation of the transformer speed controller should be in the range of -20 to +35 °C, and the relative humidity should be between 5 to 95%. Condensation of moisture in the working environment is not allowed.
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