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نمایش سبد خرید
Fan lows
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کنترل سرعت فن با استفاده از کنترل کننده (فرکانس) امکان پذیر است. با تنظیم فرکانس ، ظرفیت ، فشار و مصرف برق مرتبط نیز تغییر می کند.
از اختصارات زیر در فرمول های زیر استفاده شده است:
FAN LAWS
Change in frequency (revolutions)
| Relevant formula’s | |
|---|---|
| Capacity: | Q |
| Pressure | Pa |
| Frequency | Hz |
| Absorbed Power: | Popg. |
| Speed: | n |
Capacity (Q) and speed (n) both have the same formula
(Hz2 / Hz1) x Q1 = Q2
(Hz2 / Hz1) x n1 = n2
Pressure (Pa) (to the 2nd power)
(Hz2 / Hz1) ² x Pa1 = Pa2
Absorbed Power (Popg.) (to the 3rd power)
(Hz2 / Hz1) ³ x Popg.1= Popg.2
Calculation examples:
(Hz2 / Hz1) ³ x Popg.1= Popg.2
Data: 15,000 m³/ hour at 500 Pa at 50Hz (1.400 rpm) with an absorbed power of 2.1 kW. The frequency is reduced from 50 to 30Hz. This has the following implications.
| The new values are calculated using the formulas given above: | |
|---|---|
| Speed: (30/50)x1.400 | 840 rpm. |
| Capacity: (30/50)x15.000 | 9.000 m³/ hour |
| Pressure: (30/50)²x500 | 180 Pa |
| Absorbed Power: (30/50)³x2.1 | 0.45 kW. |
The calculation can also be reversed.
To reduce the m³/ hour from 15.000 to 7.500, the frequency can be calculated using the same formula.
(Hz 2/Hz 1) x Q1=Q2
(Hz2 /50) x 15.000=7.500 → Hz2=(7.500/15.000)x50= 25 Hz
Reduce pressure from 500 to 125 pa. The frequency can be calculated using the same formula.
(Hz 2/Hz 1) ² xPa1=Pa2
(Hz2/50)²x500=125 → Hz2=( 125/500)x50 = 25 Hz
To reduce the power from 2.1 to 0.2625 kW, the frequency can be calculated using the same formula.
(Hz 2/Hz 1) ³ x Popg.1=Popg.2
(Hz2/50)³x2.1=0.2625 → Hz2 =( 0.2625/2.1)x50= 25 Hz
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