How does the transformer for heating concrete

The pace of construction should always fit into the design framework, despite the weather conditions, so work is usually carried out in full scale in winter, and in order not to be hampered by frost, use heating transformers for concrete.

The power of such units is different, but the objects also differ in volume, moreover, this method acts as an accelerator, so winter does not affect the speed of production. Below we will tell a little about such units and methods of their use, as well as show you additionally the video in this article on the same topic.

Low frequency transformer and concrete

Principle of operation

For casting monolithic structures at temperatures below -4? C, they resort to different methods of heating the concrete mass, these are infrared emitters, and a heated solution, and warm formwork, and anode heaters. But the most effective and economical can be called the heating of concrete with the help of a low-frequency transformer and wire PNSV (Steel Heating Wire Vinyl insulation).

Before connecting the transformer for concrete heating, hinges from the PNSV wire with a cross section of 1.2 mm are placed on the reinforcement cage.² up to 3 mm². This cable is able to warm to a temperature of 80? C, thus heating the solution to 40? C-50? C, and all this happens at air temperatures from -4? C and below. To achieve the most optimal concrete heating in frosty conditions, about 60m of PNSV-1.2 will be required per cubic meter of solution.

При укладке петель следует соблюдать осторожность, чтобы не замкнуть цепь, то есть, когда вы подвязываете провод к арматурному каркасу, его изоляция (ПНСВ) попросту может перетереться о металл и петля перегорит. В таком случае определённый участок заливки останется без обогрева, что может привести к деструкции общей массы и, как следствие, железобетон окажется некачественным (см.также статью «Покраска бетонного забора: как получить долговечное покрытие»).

Для прогрева инструкция позволяет использовать такие трансформаторы, как КТП-06-20, KTPTO-80, КТП-ОБ-160, ТСДЗ-63 и так далее.

Note. For correct operation of the heating circuit, the PNS wire must necessarily be inside the concrete mass (the connection is made with aluminum wire). If the PNSV is left open, it will simply burn out.

Oil transformer. Specifications

Transformer сухой. Технические характеристики

Preparation for work and launch

Чтобы яснее представлять себе цикл подключения и рабочий запуск, ниже будет приведена инструкция трансформатора для прогрева бетона KTPTO-80 (см.также статью «Бетонные панели для забора – преимущества и установка»).

All work on the heating of injected concrete should be performed in compliance with SNiP 111-4-80 / ch.11 and GOST 12.1.013-7, which regulates the order of work and electrical safety.

• First of all, KTPTO must be zeroed out, and this can be done by connecting the power cable (its fourth core) to terminal N of the XT6 unit, thus connecting it all to the metal control cabinet. The transformer is grounded from a sled - there is a special bolt for connecting the circuit, and a steel wire of at least 4 mm is used for the connection.
• Before connecting the step-down transformer to the network, you need to check the insulation resistance with your own hands, which should not be less than 0.5 MΩ, and also pay attention to the density of the contact connections. Traveling switches SQ1 and SQ2 must be installed so that when opening the cover of the transformer casing and PU there is a possibility of reliable closing of the contacts SQ1 and SQ2. In addition, it is imperative to check the fuses in case of a short circuit.
• Переключатель силового трансформатора выставляем на 55В, что будет соответствовать положению 1, а автоматический выключатель вместе с переключателем SA3 устанавливаем в положение «ВЫКЛ».
• After this, the heating circuit installed in the formwork can be connected to the supply cable, which, in turn, is connected to the terminal block XTB.

• At the KTPTO input, we supply 380V power and turn on QF1 after checking the voltage on HL1 and HL3 and after that, using the emergency shutdown button SB1, make a control shutdown, after which QF1 is restarted. KL1 is powered by the button SB3, after which the magnetic starter KM1 should operate.
• To switch modes of operation, you need to lift the cover on the transformer case and then through the limit switch SQ1 QF1 automatically turns off. Then switch the voltage steps and turn on QF1 and KM1.

Note. Considering that the food chain during the heating of concrete can be life-threatening, only trained personnel who have received safety training instructions are allowed to service the GTPE. In addition, such workers should be able to provide first aid in time for electric shock.

Conclusion

For home use, you can rent a used step-down transformer, as it will not be useful anywhere else besides the construction site. In addition, if the volume of concrete pouring is small, then you can use a welding machine as a transformer.