Technical Reference Manual – SB-293
Printing Date
01838-002 Rev. 3.0
July-1998
Page 9 of 32
System Cautions
Transient Suppression
Voltage transients are electrical surges or spikes conducted through power, input, or output lines.
Transients are generated when electric devices (such as electric locking devices) are turned on or off.
Transients may affect the operation of the SB-293 satellite board. Because of this, transient
suppression is required for the SB-293 satellite board. A transient suppressor is a device added to an
electrical circuit that minimizes the affects of transients. Depending upon the application, a transorb or
an isolation relay provides the suppression necessary to ensure proper operation of the access
control system.
Under normal circumstances, a 1.5KE39C transorb must be installed across the positive and negative
power lines at the electric locking device to provide the best operating conditions for the SB-293
satellite board. This transorb will prevent any transients that may be generated by an electric locking
device from affecting the operation of the SB-293 satellite board. Two bipolar transorbs are provided
with each SB-293 satellite board for this purpose.
In applications such as parking gates or turnstiles (or any application using a large electric motor), a
transorb alone may not provide enough suppression; an isolation relay may be required. For ease of
installation, Keri Systems offers an Isolation Relay Package (Keri Systems p/n IRP-1) which can
provide suppression for the large transients generated by these types of devices.
SYSTEM INFORMATION