Wednesday, September 13, 2006

Trigger signals from frequency divider

Sometimes the signal from the frequency divider was strange. We used two frequncy divider, No.1 is 2 times divider, No. 2 is 10 times. The seed pulses with 4 Hz repitation rate was divided to 0.2 Hz by these frequncy dividers. I found the No.1 sent disordered signals. After moved this divider from one rank to the another, the problem was disappeared. So I used the same DC power supply to energize these dividers now.

The Relay K4 for cooling fans could not run well, previously it became well after only tightening the connectors. Yesterday I had to tighten many times, I replaced it this morning.

1 comment:

Randy said...

As you may recall, John and I replaced Relay K1 (it appeared to have a burnt contact) and did notice some loose connections on Relay K4 that John tried to make tighter. We replaced the fans with impedance protected units because we thought that maybe the outer fan on the North side had sometimes stopped turning and might have drawn too much current. We measured the Control Current to the North side as about 1.5 amps AC at startup and later 1.9 amps when running. Since the Control Current Circuit Breaker for the North side is rated at 3 amps AC , we never figured out how the K1 relay contacts could have been burnt since these contacts are rated for 10 amps AC.