CABINET AIR TEMP

• BACKGROUND
• SIGNAL SOURCE
• SIGNAL DESTINATION
• LIMITS AND FAULTS

 

 
 
 

BACKGROUND


---


Cabinet blower assembly B3 (see figure 11-9) draws filtered air into the transmitter cabinet through the air inlet duct and provides the main source of airflow in the transmitter cabinet.  The air diffuser baffle divides divides the airflow leaving the cabinet blower.  Part of the air moves vertically through the plenum assembly, upward through the left bay, and then into the top bay.  The remainder moves horizontally into the cross flow duct.  Air exiting the cross flow duct travels upward through the right bay and then into the top bay.  Air baffles mounted on the inner walls of the left and right bays ensure an even distribution of cooling air.  Air entering the top bay leaves the transmitter cabinet through the cabinet air outlet duct.  Cabinet Air Temperature thermostat S13 (see figure 11-10) mounted on a bracket over the air outlet duct opens when the transmitter exhaust air temperature reaches 167 deg. F (75 deg. C).
 

SIGNAL SOURCE


---


The signal source is +28 volts originates from PS3 via A3TB1 (see 11-7 sheet 18).  28 volt is present across S13 and K6 Relay (a normally closed relay) is held open as long as S13 is closed.  When S13 reaches 167 deg. F. it opens, causing K6 to close to light the Cabinet Over Temp DS6.
 

SIGNAL DESTINATION


---


When S13 open, the signal CABAIRTEMP leaves via bubble 1881-9 for Control and Monitoring's RMS interface A3 at Bubble 1881 (see 11-7 sheet 9) to be placed on the Fault Bus at Port02EN- as Transmitter Data (TDATA).  This signal is also used the disable the transmitter at bubble 905-11 and it leaves the RMS interface for the Fault Display Panel at bubble 914-1 as CABAIRTMP-.  At bubble 914 (see figure 11-7 sheet 1) signal CABAIRTMP- goes out to light the Cabinet Air Temp lamp.
 

LIMITS AND FAULTS


---


Both the Cabinet Over Temp lamp on the Power Distribution panel and Cabinet Air Temp fault lamp on the Fault Display Panel A1A1 will light went S13 reaches 167 deg. F.
 

Main Menu