• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

HT25/30/35CD Phase Monitor Relay

boiseengineer

boiseengineer

Are those 11-pin Octal socketed phase monitor modules available outside of Harris anymore?
Can't find them.
190-240 VAC 3-phase
 
Don't know exactly what Harris was using in that series transmitters for the three phase power monitoring, but try looking at the TimeMark Model 2522.

I am having to go from memory, but I am thinking that is what is in our Harris DX-200 power blocks. Can't get to the unit or our spare parts at the moment and confirm for you.
 
Well, that was the one which came to mind.

I am not at work and can't look at the transmitter to see exactly what Harris used.

If nothing else, a plug and adapter cable?
 
Well, the search engines failed me at home.
please stand by....
The TimeMark will probably work. Harris schematic needs to be looked at in two places as usual.
 
Need two SPDT relay contacts that the 8-pins don't have. Would like to avoid adding a slave relay or re-wiring the thing.
.
The line voltage up there normally ranges from 190 to 215 phase-phase so the origionals are set for
190 as the low point. Range has to be 190 ~ 240.
 
Looks like the SLA-230-ALA would do it.

Also a note on the HT/HD transmitter with regards to the 3-phase monitor and AC restart. I noted a quirk a few years ago with AC restart unreliability while operating the exciter (flexstar) on a UPS. I can't recall exactly, but possibly after a brief outage the transmitter does not restart properly, it appears to count on the Flexstar rebooting during the outage and adding some delay to the process. The cleanest way I could solve this was to add a time delay relay (set for approximately 3 seconds) energized by the phase monitor contacts, and the interlocks moved to the time delay relay. So now, when power is applied to the transmitter the logic has three seconds to get it's head straight before restarting, this solution was 100% successful for us.

I think this came up when we decided to change the generator transfer switch action and add a 2 second transition delay between emergency and commercial power, I believe, when the Flexstar exciter used to be in the transmitter it would lock-up sometimes when the transfer switch was quick, and generally the Flexstar exciter will lock-up for other reasons, so we moved it to a double conversion UPS which caused the other problem. The sad thing about the Flexstar is after many software updates over the past 5 years, it may be better, but still not rock solid reliable and stable while operating FM/HD like the Nautel products are.

I've had the same issue with other Harris transmitters at other sites with generators, whether it be "quick switching" or transition delayed, some transmitters will infrequently fault, causing operator intervention to turn them back on. The transmitters I've experienced this with is the Harris SX5 and Gates 5, both types will give you a "over voltage fault" every so often during the generator switching process. My solution for all of these rigs was to add a time delay relay after the phase monitor set to 3 seconds delay before closing the interlock. This modification is a 100% guaranteed solution to this issue, which I experienced here and there over my career. Some engineers take a different approach, they increase the PA voltage overload threshold to max level to reduce the occurrences, which is the wrong approach.

As always, if you modify your rig please document it on the print and manual....for the next guy!

yelloradio
 
If you still have the original, presumably failed, relay, disassemble it and check the large electrolytic inside. More than likely it will be a fraction of its rated value. Replace it a "poof"; the relay will work once again. Been there, done that. Hate to pay Harris for their over priced parts. If this isn't the problem, SSAC may have a similar item.
 
Some engineers take a different approach, they increase the PA voltage overload threshold to max level to reduce the occurrences
Click to expand...
Or, over-fill the dashpots.

We want at least one spare 1K5 phase monitor.
 
boiseengineer said:
Need two SPDT relay contacts that the 8-pins don't have. Would like to avoid adding a slave relay or re-wiring the thing.
.
The line voltage up there normally ranges from 190 to 215 phase-phase so the origionals are set for
190 as the low point. Range has to be 190 ~ 240.
Click to expand...
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom