Edwards Signaling Beacon Inrush Current Application Information

AEBN: 120307

Date: 12/3/07

Subject: Beacon Inrush Current

In addition to the nominal current rating for a beacon, often times there is an inrush
current and, for flashing beacons, a repetitive surge current. These currents can play a
factor in the design of a system.

Inrush current is the current drawn by the beacon when it is first turned on. Inrush
current can be very high, but usually only lasts for a short duration, typically less than a
few milliseconds.

Repetitive surge current is drawn by the beacon each time it flashes after it's powered up
(so a steady beacon would not have a repetitive surge, but may have an inrush current).
Repetitive surge currents can also be quite high and last up to a few milliseconds, but
usually not as high as the initial inrush.

Although a beacon may have a relatively small nominal current rating, sizing your power
source just based on that can cause problems. A 3 amp power source, for example, may
appear capable of handling six beacons with a 500mA nominal current rating, but if those
beacons have a substantial inrush or surge current, and the power source is not "stiff"
enough or capable of handling the higher currents for short durations, the beacons may
not work properly, if at all. This can also affect wire run distances. A beacon near the
source may work, but one at the far end may not.

Generally, one or two beacons on a circuit with an inrush or repetitive surge current
substantially higher than the power source's rating is usually Ok. A 120VAC strobe with
a 30A inrush, for example, will probably still work on a circuit rated for 15 amps. This is
because the duration of the inrush is very short.

However, if you have a situation requiring multiple beacons turning on at the same time
and your power source cannot handle the inrush or surge currents, there are a couple
things you can try:

1. If it's an AC powered beacon, try reversing the hot and neutral connections to half
the units. This way some will fire off the positive side of the wave, the others the
negative.

2. Don't power all the beacons from the same circuit (this might require a multi-pole
switch, one pole per circuit, to turn them all on).

3. Use time delay relay(s) set for different times so that the beacons do not all turn
on at exactly the same time. Even a fraction of a second difference could be
enough to separate the firing times and alleviate the problem.

On the following pages is a list of most of the beacons we offer and their respective
current ratings. We have not, to date, tested all of our beacons for inrush and repetitive
surge currents, so some values may be blank. Do not assume there is no inrush or surge
if it's blank. You can call Tech Support if you want to verify a value or if a beacon is not
on the list. Also refer to the beacon's installation instructions for additional information.

Current Ratings for Edwards Beacons

Edwards Model # Current Rating Voltage Rating Peak Inrush Current Repetitive Surge Current

48FIN*-N5-25WH 0.20A 120 VAC 1.3A SD 8mS (1Hz)

48FIN*-G5-20WH 0.80A 24 VAC 2.2A SD 8mS (1Hz)

48FIN*-E1 1A 12 VDC 3.5A ED 100mS (1Hz)

48FIN*-G1-20WH 0.80A 24 VDC 2.2A ED 100mS (1Hz)

48FLED*-G1 0.065A 24 VDC 0.070A

48FLED*-N5 0.025A 120 VAC 0.090A SD 8mS (60Hz)

48SIN*-N5-25WH 0.20A 120 VAC 0.8 SD 8mS (60Hz)

48SIN*-G5-20WH 0.80A 24 VAC 1.25A SD 8mS (60Hz)

48SIN*-E1 1A 12 VDC 1.1A

48SIN*-G1-20WH 0.80A 24 VDC 0.90A

48SLED*-G1 0.065A 24 VDC 0.070A

48SLED*-N5 0.025A 120 VAC 0.090A SD 8mS (60Hz)

49*-N5-40WH 0.30A 120 VAC 0.47 SD 8mS (60Hz)

49*-R5 0.1A 240 VAC

50*-N5-40WH 0.30A 120 VAC 2.0A SD 8mS (1Hz)

50*-R5 0.1A 240 VAC

50*-G5-20WH 0.80A 24 VAC 2.2A SD 8mS (1Hz)

50SIN*-N5-40WH 0.29A 120 VAC 0.47 SD 8mS (60Hz)

51*-N5-40W 0.29A 120 VAC 0.9A SD 8mS (1Hz)

51*-E1 1A 12 VDC 3.5A ED 100mS (1Hz)

51*-G1 1.1A 24 VDC 3A ED 100mS (1Hz)

51SIN*-G5-20W 1.1A 24 VAC

51SIN*-G1 0.80A 24 VDC 0.90A

51SIN*-N5-40W 0.29A 120 VAC

52*-N5-40WH 0.35A 120 VAC 0.47 SD 8mS (60Hz)

52*-G5-20WH 0.80A 24 VAC 1.25A SD 8mS (60Hz)

52*-R5 0.1A 240 VAC

53*-E1 1.8A 12 VDC 2.0A

53*-G1 1A 24 VDC 1.1A

53D*-GW 1A 24-28V

57EDF*-G1 2.2A 24 VDC 40A @ 100uS 4.5A @ 100uS

57EDF*-N5 0.2A 120 VAC 20A ED 300uS (1Hz)

57EDF*-R5 0.1A 240 VAC

58*-N5-100WH 1A

89STR*-AQ 0.158A 24 VAC

89STR*-AQ 0.219A 24 VDC

89STR*-N5 0.09A 120 VAC

89SMSTR*-AQ 0.158A 24 VAC

89SMSTR*-AQ 0.219A 24 VDC

89SMSTR*-N5 0.09A 120 VAC

90*-N5 0.1A 120 VAC 50A ED 1mS (1Hz)

91B-* 0.5A 12 VDC

92*-N5 0.1A 120 VAC 50A ED 1mS (1Hz)

92*-R5 0.05A 240 VAC

92PLC*-N5 0.1A 120 VAC 20A ED 75uS (1Hz)

92PLC-DF*-N5 0.1A 120 VAC 20A ED 75uS (1Hz)

93*-N5 0.1A 120 VAC

93*-R5 0.05A 240 VAC

93DF*-N5 0.1A 120 VAC 40A @ 70uS 12A @ 500uS

93DF*-R5 0.05A 240 VAC

120 VAC