Surge Protection for Public Address Systems White Paper
Total Page:16
File Type:pdf, Size:1020Kb
Surge protection for public address systems White Paper Contents Surge protection for a public address system Structure with horn loudspeaker with and without lightning pro- tection system www.dehn-international.com Surge protection for public address systems White Paper Public address systems are used for voice, music and alarm Loudspeakers with different power ratings can be jointly used transmission. To this end, the useful signal is modulated onto a in a line or group. The minimum power of the amplifier is the carrier voltage (50 V, 70 V, 100 V) and reaches the loudspeaker sum of the individual loudspeaker power ratings in the pub- via a transmitter. This transmitter transforms the low imped- lic address system. When determining the minimum power of ance of the loudspeaker to a higher value, thus reducing the the amplifier, the sum of the loudspeaker power ratings is not current. Therefore, telecommunication lines with a diameter of decisive, but instead the sum of the selected power ratings at 0.6 mm or 0.8 mm can be used. the transmitters. There are different kinds of loudspeakers. Flush and wall loud- Subsection 7.2.1 of the EN 50174-2 standard describes the pro- speakers typically have a rated power between 6 and 30 W, tection from lightning strikes and induced surges and compares column loudspeakers between 20 W and 100 W and horn loud- the risk of damage with the risk which is accepted by the oper- speakers between 10 W and 60 W. Modular amplifiers have a ator. If this risk assessment reveals that surge protection meas- rated power between 100 W and 600 W (in some cases even ures are required, surge protective devices must be installed higher). for the relevant installations and systems in need of protection. 100 V loudspeaker MEB power amplifier 100 V relay module 100 V loudspeaker MEB DCF 77 antenna CD player MEB 230 V system RS 232 tuner MEB intercom with function and MEB selector buttons central unit 230 V system with input slots MEB 75 Ω coaxial cable No. Surge protective device Part No. No. Surge protective device Part No. DR M 2P 150 (current > 1 A – 25 A) or 953 204 BXT ML2 BD HFS 5 920 271 + BXT BAS 920 300 BXT ML4 BE 180 (current < 1 A) 920 327 + BXT BAS 920 300 DR M 2 P 255 953 200 DGA G BNC 929 042 DGA FF TV 909 703 FS 9E HS 12 924 019 DPRO 230 909 230 Figure 1 Modular public address system with surge protective devices 2 WP008/E/0515 © Copyright 2015 DEHN + SÖHNE Surge protection for public address systems White Paper protective angle s MEB MEB No. Surge protective device Part No. No. Surge protective device Part No. DR M 2P 150 (current > 1 A – 25 A) or 953 204 DR M 2P 150 (current > 1 A – 25 A) or 953 204 BXT ML4 BE 180 (current < 1 A) 920 327 BXT ML4 BE 180 (current < 1 A) 920 327 + BXT BAS 920 300 + BXT BAS 920 300 Figure 2 Horn loudspeaker installed on a structure without external Figure 3 Horn loudspeaker located in the protected volume of lightning protection system an air-termination system on a structure with external lightning protection system In the following, further applicable regulations will not be the power of the amplifier or loudspeaker (group) and U is the specified (e.g. German Sample Directive on Fireproofing Re- carrier voltage. quirements for Line Systems (MLAR), building regulations, reg- ulations concerning electroacoustic emergency warning sys- All earth connections of the surge arresters in the vicinity of tems, regulations concerning burglar and fire alarm systems). the public address system must be connected to a nearby com- mon potential point. Large-scale public address systems feature a modular 19” de- sign (Figure 1) and are frequently located in close proxim- If exterior loudspeakers are located on the roof of a building, ity to a permanently manned workstation. In such cases, the they can be damaged by indirect lightning effects (inductive / relevant length of the connecting cable to the PC or intercom decides whether the surge arresters shown (4 + 5) must be in- capacitive coupling) in case of systems with external light- stalled. If this length exceeds 5 m, surge protective devices are ning protection system (Figure 3) and without exter- required. nal lightning protection system (Figure 2). If the system is equipped with an external lightning protection system To be able to dimension the surge arresters for the loudspeak- (Figure 3), the exterior loudspeaker is reliably protected from er lines (1 + 2), the maximum current I in the relevant branch direct lightning strikes since it is located in the protected vol- must be determined by means of the ratio I = P/U where P is ume of an air-termination system. WP008/E/0515 © Copyright 2015 DEHN + SÖHNE 3 White Paper: Surge protection for public address systems DEHNrail DR M 2P 255 (953 200) ■ Two-pole surge arrester consisting of a base element and plug-in protection module ■ High discharge capacity due to heavy-duty zinc oxide varistor/spark gap combination ■ Energy coordination with other arresters of the Red/Line product family Figure without obligation Basic circuit diagram DR M 2P 255 Dimension drawing DR M 2P 255 Two-pole surge arrester consisting of a base part and plug-in protection module Type DR M 2P 255 Part No. 953 200 SPD according to EN 61643-11 Type 3 SPD according to IEC 61643-1/-11 Class III Nominal a.c. voltage (UN) 230 V Max. continuous operating a.c. voltage (UC) 255 V Max. continuous operating d.c. voltage (UC) 255 V Nominal load current a.c. (IL) 25 A Nominal discharge current (8/20 µs) (In) 3 kA Total discharge current (8/20 µs) [L+N-PE] (Itotal) 5 kA Combined impulse (UOC) 6 kV Combined impulse [L+N-PE] (UOC total) 10 kV Voltage protection level [L-N] (UP) ≤ 1250 V Voltage protection level [L/N-PE] (UP) ≤ 1500 V Response time [L-N] (tA) ≤ 25 ns Response time [L/N-PE] (tA) ≤ 100 ns Max. mains-side overcurrent protection 25 A gL/gG or B 25 A Short-circuit withstand capability for mains-side overcurrent protection with 25 A gL/gG 6 kArms Temporary overvoltage (TOV) [L-N] (UT) 335 V / 5 sec. Temporary overvoltage (TOV) [L/N-PE] (UT) 400 V / 5 sec. Temporary overvoltage (TOV) [L+N-PE] (UT) 1200 V + UCS / 200 ms TOV characteristic [L-N] withstand TOV characteristic [L/N-PE] withstand TOV characteristic [L+N-PE] withstand Operating temperature range (TU) -40°C...+80°C Operating state/fault indication green / red Number of ports 1 Cross-sectional area (min.) 0.5 mm2 solid/flexible Cross-sectional area (max.) 4 mm2 solid/2.5 mm2 flexible For mounting on 35 mm DIN rails acc. to EN 60715 Enclosure material thermoplastic, red, UL 94 V-0 Place of installation indoor installation Degree of protection IP 20 Capacity 1 module(s), DIN 43880 Approvals KEMA, VDE, UL, VdS, CSA Weight 81 g Customs tariff number 85363030 GTIN 4013364108301 PU 1 pc(s) 4 WP008/E/0515 © Copyright 2015 DEHN + SÖHNE White Paper: Surge protection for public address systems DEHNrail DR M 2P 150 (953 204) ■ Two-pole surge arrester consisting of a base element and plug-in protection module ■ High discharge capacity due to heavy-duty zinc oxide varistor/spark gap combination ■ Energy coordination with other arresters of the Red/Line product family Figure without obligation Basic circuit diagram DR M 2P 150 Dimension drawing DR M 2P 150 Two-pole surge arrester consisting of a base part and plug-in protection module Type DR M 2P 150 Part No. 953 204 SPD according to EN 61643-11 Type 3 SPD according to IEC 61643-1/-11 Class III Nominal a.c. voltage (UN) 120 V Max. continuous operating a.c. voltage (UC) 150 V Max. continuous operating d.c. voltage (UC) 150 V Nominal load current a.c. (IL) 25 A Nominal discharge current (8/20 µs) (In) 2 kA Total discharge current (8/20 µs) [L+N-PE] (Itotal) 4 kA Combined impulse (UOC) 4 kV Combined impulse [L+N-PE] (UOC total) 8 kV Voltage protection level [L-N] (UP) ≤ 640 V Voltage protection level [L/N-PE] (UP) ≤ 800 V Response time [L-N] (tA) ≤ 25 ns Response time [L/N-PE] (tA) ≤ 100 ns Max. mains-side overcurrent protection 25 A gL/gG or B 25 A Short-circuit withstand capability for mains-side overcurrent protection with 25 A gL/gG 6 kArms Operating temperature range (TU) -40°C...+80°C Operating state/fault indication green / red Number of ports 1 Cross-sectional area (min.) 0.5 mm2 solid/flexible Cross-sectional area (max.) 4 mm2 solid/2.5 mm2 flexible For mounting on 35 mm DIN rails acc. to EN 60715 Enclosure material thermoplastic, red, UL 94 V-0 Place of installation indoor installation Degree of protection IP 20 Capacity 1 module(s), DIN 43880 Approvals KEMA, VDE, UL, VdS, CSA Weight 79 g Customs tariff number 85363030 GTIN 4013364109704 PU 1 pc(s) WP008/E/0515 © Copyright 2015 DEHN + SÖHNE 5 White Paper: Surge protection for public address systems DEHNprotector DPRO 230 (909 230) ■ Surge protection with monitoring device and disconnector ■ Visual operating state (green) and fault indication (red) ■ Enhanced safety due to fault-proof Y protective circuit Figure without obligation Basic circuit diagram DPRO 230 Dimension drawing DPRO 230 Surge protective adapter with integrated child lock. Type DPRO 230 Part No.