Notification Appliances—E Series Speakers and Strobe Speakers 19
The peak inrush current waveforms for the strobe of the E series strobe speakers are
shown below (Figure 9). Circuit fuses, control devices for the NAC, and power supplies
must be rated to handle this inrush. Current limitations will not prevent the startup unless
the power supply current limiting is achieved by a fast reacting voltage fold-back circuit.
Therefore, if the power supply does not have a fast reacting voltage fold-back circuit, the
power supply ratings can be based on the rated (steady state) current draw (Figure 9).
Make sure the system power supply is compatible with the specified inrush current.
!
WARNING:
Personal injury hazard. Ensure all fuses used on NACs are
rated to handle the maximum inrush or peak current from all
devices on the circuit. Failure to do this may result in loss of
power to the NAC and the failure of all devices on that circuit
to operate.
Note:
Inrush current refers to current that exceeds the nominal voltage when the strobe
is first turned on. Once the strobe is turned on, it flashes one flash per second.
Peak current indicates the current rising above the nominal voltage right after
each strobe flash.
To calculate the maximum inrush or peak current:
1.
Use Table 2 to determine the highest value of rated inrush current or rated peak
current (whichever is higher) for an individual strobe.
2.
Measure across the expected operating voltage range of the strobe.
3.
Multiply this value by the total number of strobes on the circuit.
4.
Add the inrush or peak currents from any other devices on the circuit and include
any required safety factors.
Figure 9: DC Strobe Current Waveforms
Peak Inrush
Current
strb _1
Pe
rc
e
n
t
0
DC S trobe S teady State C urrent W aveform
(as p er cen t of rated cu rr ent )
T ime (M icrosec onds)
2 5 0
2 0 0
1 5 0
1 0 0
5 0
3 0 0
1 0 0
2 0 0
3 0 0
4 0 0
Rated
C urren t
Maxim um V oltage
Nom inal Voltage
Pe
rc
e
n
t
0
DC S trobe or P eak Inru sh C urren t
(as perc ent of rated c urrent)
Tim e (M illis econd s)
400
250
200
150
100
5 0
350
300
1
2
3
4
5
6
Maxim um V oltage
N ominal V oltage
4 0 0
