Line placing main point:

       The installment key point is the layout, to meet the fire requirements, the nema uses the being flame-resistant trunking or the being flame-resistant nema. Each wiring point and the branching point suppose the branch box. In order to be advantageous for the trouble shooting, after pulling the line, then uses the avonmeter to survey. The line terminal pipe nipple, surveys first with the avonmeter in the beginning end. If leads the way proved that the line has the abruption question. If resistance close zero, the terminal opening, the resistance should be again the infinitely great. Otherwise, if the resistance is not the infinitely great proved that between two lines has the short circuit question. Moreover, but also whether there is can survey between a winding and the nema to short-circuit the leakage phenomenon. Each attire section of lines must inspect immediately, then according to the design drawing bring home, inspects each area to the fire center impedance and so on to design whether to have discrepancies. Finally joins the power amplifier, the audition each area sound to be whether normal. Because each area loudspeaker locates the position is different, covers the region size also to have the difference, to enable the sound field to achieve the predetermined uniformity, may adjust the loudspeaker (space transformer) on amount of power, the majority of loudspeakers have two kind of size different power output, may choose the suitable power according to the place to the volume size request.

 

The wire rod selects the skill:

        Available transparent, but not necessarily must with transparently, the transparent wire rod possible price expensive spot, to use RVV generally (two cores) pure copper wire line. Buys when the wire rod must measure that the impedance, the normal pure copper wire 1mm2 100 meters impedance should be 2 ohms, if the impedance is too big, explained that has the possibility is the copper alclad, or is the copper coated iron line.

 

Chooses the wire rod thick thin computational method:

1. Based on the ohm theorem, line loudspeaker impedance R=U2/P, the broadcast uses the 100V voltage, namely R=1002/P=10000/P (P is known value, namely for this lines on loudspeaker power sum total). Example: On some lines loudspeaker total output is 200W, then this lines loudspeaker impedance is, R=10000/200=50 Europe.

 2. In order to guarantee that the transmission line loses does not surpass 25%, then transmits return routes impedance not to surpass the loudspeaker total impedance 30%. On the example, the line loop impedance should be: 50 ohm x30%=15 Europe, unilateral is 15 ohm /2=7.5 Europe.

3. Therefore we when chooses and matches the wire rod, must first measure that the wire rod hundred meter impedance is how many, must guarantee that lines total length (rice) the /100x wire rods hundred meters impedance must be smaller than R=(1002/P)x30%/2.

 

Broadcast system wiring example calculation - - comprehensive reference chart