The control mode of silicon-molybdenum rod electric heating system should be triggered by phase shift.

The electric heating control mode of silicon molybdenum rod should adopt phase shift triggering mode. Because the on-off control mode triggered by zero-crossing will generate inverter voltage on the secondary side of the transformer connected with the load of the silicon molybdenum rod, this voltage will be superimposed on the output voltage, which will generate large voltage and load on the electric heating silicon molybdenum rod, and generate large current, leading to the damage of the silicon molybdenum rod.

Third, the heating step of silicon molybdenum rod electric heating furnace

1. After the end of the electric heating furnace, it can formally start heating.

In order to avoid excessive current impact damage to electrical equipment, it is recommended to start the electric furnace according to the following steps and parameters:

Note: The shift time should not be too long, and the temperature of general components should not drop by 300~ 400, otherwise it is easy to cause current impact and damage to electrical equipment.

2. Electric heating process of silicon molybdenum rod in high temperature electric furnace (actual usage parameters)

The electric heating process of silicon molybdenum rod in high temperature electric furnace is divided into two parts:

1, below 300 degrees according to manual output temperature control;

2, more than 300 degrees to switch to the time program temperature control.

(1) When the temperature is lower than 300 degrees, it is controlled by manual output temperature

Start power-on, switch to manual mode, adjust the output value to 5%, and observe the current in real time (this current is the actual current of the load, please note the difference with the current displayed on the KSY-P interface), 10% above 50 degrees, 25% above 100 degrees; The current in the first 20 minutes should not exceed 50A, that is, 1/3 of the operating voltage; 1 hour before the current does not exceed 100A, that is, 2/3 of the operating voltage. Note: Heat up to 300 degrees in this way. (2) over 300 degrees to switch to the time program temperature control.

Manually adjust the temperature to more than 300 degrees, switch to the time program mode, according to the time program control. The control parameters are set as follows:

Four, silicon molybdenum rod electric heating precautions

According to the structure, working atmosphere and temperature of the heating equipment, the correct selection of the surface load of the heating element is the key.

1. Silicon molybdenum rod heating element should not be used in the temperature range of 400~ 700, because in this unfavorable condition, the element will be oxidized at low temperature, leading to its destruction and powder;

2. Silicon molybdenum rod heating element is suitable for air and neutral environment. Hydrogen and other reducing atmosphere will destroy the protective layer, chlorine and sulfur vapor will directly damage the components;

3. The heating rate of silicon-molybdenum rod should not be too fast, which is 4/min in actual case;

4. Observe the load current when the silicon molybdenum rod is heated.