Ballmill with inverter, cost saving?

Jaman inverter sudah melanda kesegala bidang, termasuk juga pabrik keramik.
Nah ballmill salah satunya, dengan iming iming terjadi penghematan.
Betulkah? Adakah yg pernah menghitung BEP nya?

dibawah ini ada seorang yg melakukan pengukuran, dengan syarat ballmill di operasi kan normal full capacity dengan motor standar ABB ataupun Siemens.

saya kutip, kutipan tercatat di hdd saya, hanya source link internet tidak/belum saya ketemukan.

Application of ball mill and the function of each part.

· One, overview:

In the grinding process of the main equipment is used for ball mill, the variable speed drive, it is still a blank. Its reason is, ball mill work cylinder speed is constant, even if want to change, change range is not. Mill electrical transmission mode, the three-phase AC squirrel cage induction motor and hydraulic coupling, gear reducer, belt wheel speed reducer, or three-phase AC squirrel cage asynchronous motor, gear reducer, belt wheel speed reducer, general mill barrel as the reducer belt wheel. Ball mill heavy start-up, if the transmission link of hydraulic coupling, even with the use of autotransformer starter decompression or star - delta starter, the grid will lead to a greater impact, and often difficult to start. As the buffer starting at impact, in a transmission link joined the fluid coupling, which can successfully start in any state of ball mill.

Two, the critical speed of ball mill and optimum operating speed

Mill speed directly affects the steel ball and the movement of materials and material grinding process. In different speed, cylinder body steel ball and material movement condition. If speed is low, the steel ball and the material along with the inner wall of the cylinder is increased, when the ball and material angle equal to or greater than the natural inclination, ball slide down along the bevel, cannot form adequate gap, ball on material grinding function is small, the efficiency is very low. If the cylinder speed is very high, due to the effect of centrifugal force, so that materials and steel no longer from the cylinder wall, and rotates together with. The state is called the critical speed minimum speed. When the ball has no impact, the material was only slightly abrasive, the efficiency is very low. When the cylinder is the speed between the two, ball was brought to a certain height along a parabola falls. The ball on the cylinder bottom material produced strong impact, the highest efficiency. The highest efficiency when working speed become optimum operating speed. Ball mill power consumption and the speed of the motor is proportional to the first power, therefore, using inverter in frequency following regulate the speed of the motor can be energy-saving, energy-saving range and speed range. According to the different conditions have different adjustment range, uses the frequency conversion velocity modulation theory and energy saving in the range of 0 ~ 11%.

In three, the motor voltage regulation electricity-saving as described above, light-load motor can adjust the power supply voltage of the ways to enhance the efficiency of GB12497", the economic operation of three-phase asynchronous motor" the implementation of mandatory national standard guide for surveillance of the formula thus, variable frequency energy saving operation save energy is limited, this is because the efficiency of the motor itself high efficiency 93.5.5%, rated voltage regulation, can reduce the copper loss, iron loss and stray loss, only reduce it, but accounted for a larger proportion of the total loss of mechanical friction loss basically unchanged, so the motor efficiency is limited, such as this example saves the active power of 0.27 ( kW ), energy-saving rate is very low. However, the installation of inverter, inverter efficiency is not 100%, so not only energy-saving instead of energy dissipation. The inverter or a request for 50Hz equipment in operation, either a constant torque characteristic of load, or fan, water pump square torque load, considering not only from the energy conservation. The purpose of the reform should be to improve equipment performance and enhance the level of automation equipment, so that not only the productivity, but also the quality of products can be guaranteed. Such conditions in actual production meet the eye everywhere, such as cement and tile plant ball mill, cylinder speed by calculation or experiment data to determine, for general 16r / min ~ 18r / min, speed deviation will affect the efficiency of ball mill, so this kind of mechanical equipment with frequency converter speed even, if and the original the same speed no energy saving.

In four, the motor efficiency of a ball mill motor for 90kW, when the normal operation of the motor current is 80 ~ 110A, load rate of 62%.

As a result of the load rate is not high, the efficiency of the motor are reduced. During normal operation, the power of the motor does not exceed 55kW, taking into account the mill is a heavy starting, in order to ensure the smooth starting appropriate to increase the electrical capacity is necessary. On the surface, seem to have great energy-saving space. In fact, in order not to affect the mill's production efficiency, such as the use of variable frequency speed regulation, the inverter output frequency is still 50Hz, even though the need for speed regulation, can not be large range of adjustment, frequency range is reduced, saving energy limited. Now the general inverter are" energy saving" function, inverter frequency under the same conditions automatically adjusts its output voltage, so that the motor efficiency.

In five, a hydraulic coupler and a frequency variable speed regulation and energy-saving hydraulic coupling is achieved by controlling the working chamber of the oil of the moment of momentum change, transfer of motor energy, electric motor through a hydraulic coupler input shaft work of its own wheel, the working oil accelerated, the accelerated working oil to drive the hydraulic coupling driven work turbine, the energy transfer to the output shaft and the load. Hydraulic coupling with variable speed and torque limited branch, the former for electric drive speed regulation, the latter for motor starting. In the system of hydraulic coupler in the motor starting play a buffer role, its theory of efficiency value of 95%, converter efficiency is 96%, that is to say, in the transmission link is removed in the fluid coupling, with AC inverter driving ball mill motor, can be rated current or slightly higher than the rated current smooth starting of ball mill, and, in theory efficiency can be increased by 1%. Actually the fluid coupling hydraulic coupling efficiency and injected into the oil, in the operation process of hydraulic coupler has a certain temperature or presence of untight sealing, leakage and other factors, the efficiency is less than the theoretical value of 95%. The site has compensation capacitor, motor power factor is relatively high, frequency converter after the removal of compensation capacitor inverter itself, due to the high power factor, therefore, the power factor of system change. Thus, power saving rate should be about 5%, coupled with the front 1%, a total of 6% energy saving.

Six, summary:

Ball mill energy saving at present from the above three aspects, according to the actual situation of adjusting speed, the theory has 0 ~ 11% energy saving; the use of frequency converter in energy saving mode adjustment have less energy; in the transmission link using a fluid coupling hydraulic coupling, removed using inverter energy-saving rate of 6%, thus, the comprehensive energy saving measures the mill, inverter can still achieve energy-saving purpose.

nah, bila 6% energy saving dengan harga inverter dan coupling, berapa tahunkah  balik modal ? Lama lho, coba aja hitung deh.