After the graphite furnace is electrified, the voltage, current, power and power factor are in the constant state of change, which is related to each other. At the beginning of the power, according to the size of the stove and furnace product specifications, select the appropriate starting power and rising power. Power is the output voltage of the low-voltage side of the transformer and the corresponding current value as well as the power supply system at that time. The product of the power factor (i.e. P = eicos^>).
Because the furnace core resistance is relatively high at the beginning stage, must be supplied with a certain voltage value, the furnace core can pass the right amount of current. Therefore, if the starting power is higher then the voltage level of the starting power supply is also high (丨 > The product is the case). After a period of time, the furnace core temperature is rising, the furnace core resistance gradually decreased In the case of constant voltage, the current and power will be slow and limited when the current is increased automatically and the power is raised (more than 10 hours after starting power).
In order to increase the power of the whole furnace by the specified rising power, it is necessary to adjust the output voltage of the transformer constantly, that is, the process of graphitization of the graphite plate is gradually connected to the higher voltage level, until it is adjusted to the highest power point, the highest point of power should make full use of the rated capacity of the transformer. When the power reaches the highest point, the current does not reach the maximum rated current value of the transformer, in the case of the furnace core resistance is declining, the current through the furnace core can continue to increase. In order not to overload the transformer, to reduce the voltage in time, so that the current does not exceed the limit capacity of the transformer.
With two of the same specifications of the transformer in series or parallel transmission (or a transformer whose secondary can be in series or parallel transmission), the initial need for a higher starting voltage can be used in series transmission, but to reach the limit capacity of the transformer should be converted to parallel transmission immediately, At this time, due to the reduction of voltage into the furnace current and power has been temporarily reduced, and then continue to rise.
As a result, there will be two peak power during the entire power-up process. Although the power of the first peak power is very high, but because the transformer is limited by series transmission, the voltage is very high and the rated current is not very large; the voltage is reduced but the current can be greatly increased after being converted into parallel transmission.
After the power is no longer in accordance with the rise to adjust electricity, this is mainly to enable the current to achieve the maximum value of the transformer, and to stabilize at a higher level. When the electric stove starts to reach the maximum power, the furnace core is far from reaching the maximum temperature, and only close to the maximum temperature stage when the current of the furnace core reaches the highest point. At this time can not immediately power outages, because the current reaches the maximum value when the furnace temperature is still in an unbalanced state, so continue to electrify temperature can continue to rise.