Appendix B - Technical Bulletins
Transient Surge Suppression
Since its introduction, a number of the AL250-V2 units have been damaged by transient voltages. Units
damaged by transient voltages may exhibit the following symptoms: Unit will not power-up, discrete
inputs show ON and then OFF with no switch contact change, conductivity and/or temperature values
bounce significantly or do not change at all, keypad buttons do not work, and unit displays odd alarms or
error codes.
A transient voltage can be defined as any change in voltage, such as a spike, which is unexpected,
undesirable, and often destructive. Transient voltages are less than 8.3 milli-seconds in duration and can
range from a few milli-volts to 18,000 volts in a normal working environment. More destructive transient
voltages can be generated by electrostatic discharges, inductive switching, motor commutation, nuclear
electro-magnetic pulses, and lightning. The latter two sources generate voltage spikes into the millions of
volts.
1
Transient voltages are common through out the US, however they are more common in certain
geographic areas and may be exacerbated by environmental aspects such as: multiple story buildings,
building ground surface area larger than 38,000 ft.
2
, and buildings located more than 2000 ft. from a utility
substation. The AL250-V2 has built in power conditioning equipment; however it will not suppress all
transients.
A transient surge protector is a device which is typically used to protect electronic equipment from
damage or destruction caused by transient voltages and surge currents. These destructive transients
most often attack equipment through power input lines, signal input and output lines, data lines, and any
other wire coming into or going out of a chassis containing electronics.
1
Many companies sell transient surge protection devices. A list of some of these companies is shown
below. The list is provided for informational purposes only. No specific testing has been performed on
these products and the performance of these products is not guaranteed to be effective when used with
the AL250-V2.
Surge Suppression Manufacturers
Innovative Technology www.itvss.com
EFI
www.efinet.com
APC
www.apc.com
Tripp-Lite
www.tripplite.com
Panamax
www.panamax.com
Transtector
www.transtector.com
Maxivolt
www.maxivolt.com
The surge suppressor should be connected to the primary side of the AL250-V2 transformer as close to
the AL250-V2 power terminal blocks as possible. The conductors between the surge suppressor and the
AL250-V2 terminal blocks should be kept as short as possible.
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Axiomatic Technologies Corporation
