Link Electronics PCA-819 Audible Alarm for PCO-818 Dual Sync Generator Change-Over System

The PCA-819 Remote Changeover Alarm is an add-on enhancement to the PCO-818 changeover system. The PCA-819 is engineered to provide a convenient and easy to use means of monitoring changeover, due to loss of signal, at a remote location. Bi-color LED's provide a visual indication of the Changeover Frame status. Additionally, an audible alarm sounds to indicate an alarm condition. And to provide even more flexibility, isolated relay contacts, both normally open and normally closed, are provided so the user can control other equipment or alarms in the event of a loss of signal at the Changeover Frame. Front panel switches allow the user to disable the alarm signal from either or both, generator banks and also mute the audible alarm.

The PCA-819 is housed in a rugged 1RU rackmount enclosure and can be powered from 120 or 240VAC (internal jumper selectable). Whenever a loss of signal occurs on any of the various changeover modules in the PCO-818, an alarm signal is generated and the PCA-819 shows the alarm condition on the front panel. The PCA-819 has two Digital inputs, Gen A and Gen B. These signals are input on TB1 located on the rear panel. A three-wire cable connects TB1 to J3 on the rear of the PCO-818 frame. These signals are active high, TTL level. Input A and/or B can be disabled by their respective enable/disable switch on the front panel. The inputs are filtered for noise and clipped at 5.1V for transient protection. Bi-color LED's indicate an RED alarm condition, GREEN condition OK and BLINKING GREEN unit has been disabled.

A circuit detects if either or both inputs, Gen A or Gen B, has a failure, the speaker sounds off and the relay is energized. The speaker is a self generating audible indicator and may be muted by front panel switches. The alarm output relay provides both Normally Open and Normally Closed contacts, capable of switching up to 5 amps at 120VAC or 30VDC. Varistors and a fuse protect the contacts the relay from transient spikes and overloads. The PCA-819 is powered from the AC line, with the option of either 120V or 240V, by changing the appropriate jumpers at JP1, JP2 and JP3.