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D900-28-00 

I56-1796-011R

Wire Sizes

The designer must be sure that the last device on the circuit has 
sufficient  voltage  to  operate  the  device  within  its  rated  voltage. 
When calculating the voltage available to the last device, it is nec-
essary to consider the voltage drop due to the resistance of the 
wire. The thicker the wire, the less the voltage drop. Generally, for 
purposes of determining the wire size necessary for the system, it 
is best to consider all of the devices as “lumped” on the end of the 
supply circuit (simulates “worst case”).
Typical wire size resistance:
18 AWG solid: 

Approximately 8 ohms/1,000 ft.

16 AWG solid: 

Approximately 5 ohms/1,000 ft. 

14 AWG solid: 

Approximately 3 ohms/1,000 ft.

12 AWG solid: 

Approximately 2 ohms/1,000 ft.

Example:  Assume  you  have  10  devices  on  a  zone  and  each  re-
quires  50  mA  average  and  2000  Ft.  of  14  AWG  wiring  (total 
length=oureturn). The voltage at the end of the loop is 
0.050 amps per device x 10 devices x 3 ohms/1,000 ft. x 2000 ft 
=3 volts drop.

NOTE:

 If class “A” wiring is installed, the wire length may be up 

to 4 times the single wire length in this calculation.
The same number of devices using 12 AWG wire will produce only 
2 volts drop. The same devices using 18 AWG wire will produce 
8 volts drop. Consult your panel manufacturer’s specifications, as 
well as SpectrAlert’s operating voltage range to determine accept-
able voltage drop.

Figure 1A: Current Draw Measurements (RMS)

NOTE:

 All ‘S’ and ‘P’ models were only tested at the 8-17.5 and 

16-33  Volt-FWR/DC  limits.  This  does  not  include  the  80%  low-
end or 110% high-end voltage limits.

Strobe Current Draw

Candela 

Setting

FWR 

Operating 

Current 

Strobe

DC 

Operating 

Current 

Strobe

12V

24V

12V 24V

15

112

64

127

59

15/75

135

74

127

69

30

93

90

75

158

160

110

208

209

Figure 1B: Horn Sound Measurements (dBA):

   Selectable Horn Tones

8-17.5V

16-33V

Temporal

Low
Volume

Electromechanical

67

75

3000 Hz Interrupted

68

75

High
Volume

Electromechanical

71

80

3000 Hz Interrupted

72

81

Non-
Temporal

Low
Volume

Electromechanical

71

79

3000 Hz Interrupted

72

79

High
Volume

Electromechanical

76

84

3000 Hz Interrupted

77

86

Figure 1C: Horn Current Draw Measurements (RMS):

    

Selectable Horn Tones

DC

FWR

12V

24V

12V

24V

Temporal

Low
Volume

Electromechanical

15

23

13

23

3000 Hz Interrupted

15

33

13

23

High
Volume

Electromechanical

36

53

20

44

3000 Hz Interrupted

43

57

21

40

Non-
Temporal

Low
Volume

Electromechanical

16

37

19

29

3000 Hz Interrupted

16

32

18

33

High
Volume

Electromechanical

38

49

46

49

3000 Hz Interrupted

44

56

42

58

NOTE:

  Regulated 12 VDC, max operating current 44.4 mA

 

Regulated 24 VDC, max operating current 57.0 mA

 

12 V FWR, max operating current 45.7 mA

 

24 V FWR, max operating current 57.5 mA

NOTE:

 12VDC 2-wire horn/strobe current is shown in Figure 1D. 

24VDC 2-wire horn/strobe current is shown in Figure 1E. Current 
draw  for  other  horn/strobe  power  supplies  can  be  calculated  by 
adding the strobe current draw (Figure 1A) for chosen candela set-
ting to the horn current draw (Figure 1C) for chosen setting.

Figure 1D: 12VDC Horn/Strobe Current Draw 
 

Measurements (mA RMS)

Temporal

Low Volume

High Volume

Candela 

Setting

Electromechanical

3000 Hz

Electromechanical

3000 Hz

15

111

111

112

112

15/75

127

127

126

129

Non-Temporal

15

113

112

114

115

15/75

128

128

130

134

Figure 1E: 24VDC Horn/Strobe Current Draw 
 

Measurements (mA RMS)

Temporal

Low Volume

High Volume

Candela 

Setting

Electromechanical

3000 Hz

Electromechanical

3000 Hz

15

71

70

73

75

15/75

86

85

87

88

30

99

98

100

100

75

166

166

167

170

110

209

209

210

213

Non-Temporal

15

74

74

79

82

15/75

86

88

93

96

30

101

101

107

110

75

167

167

173

176

110

213

213

218

222

Содержание SpectrAlert S1224MCW

Страница 1: ...nal Humidity Range 10 93 RH non condensing NOTE Horn units will operate on walk tests with on time durations of 25 sec or greater Flash Rate 1 flash per second Operating Temperature 32 F to 120 F 0 C to 49 C Selectable Light Outputs All candelas are selectable via a manual slide switch 12 24 Volt Applications 15 or 15 75 candela 24 Volt Application 30 75 110 candela 15 75 is listed at 15 candela p...

Страница 2: ... 15 75 135 74 127 69 30 93 90 75 158 160 110 208 209 Figure 1B Horn Sound Measurements dBA Selectable Horn Tones 8 17 5V 16 33V Temporal Low Volume Electromechanical 67 75 3000 Hz Interrupted 68 75 High Volume Electromechanical 71 80 3000 Hz Interrupted 72 81 Non Temporal Low Volume Electromechanical 71 79 3000 Hz Interrupted 72 79 High Volume Electromechanical 76 84 3000 Hz Interrupted 77 86 Figu...

Страница 3: ...ch located on the rear of the product while watching the viewing win dow on the side of the reflector Viewing Window A0133 00 Permissible Candela Settings Candela Setting Operating Voltage 12V 24V 15 OK OK 15 75 OK OK 30 OK 75 OK 110 OK Check terminal polarity before wiring For proper operation make sure the correct wire polarity is applied to the unit WARNING Figure 3 Horn Factory Default Setting...

Страница 4: ...include a note describing the malfunction and suspected cause of failure The Company shall not be obligated to repair or replace units which are found to be defective because of dam age unreasonable use modifications or alterations occurring after the date of manufacture In no case shall the Company be liable for any consequential or incidental damages for breach of this or any other Warranty expr...

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