Garage Monster Posted June 21, 2022 Share Posted June 21, 2022 When plugged into shore power two of these contactors produce quite an annoying hum or buzzing sound and they are above the bed. I can see no numbers on them. Can anybody tell me how to source new ones without removing one first? Ant help will be appreciated. The coach is a 93 Monaco. Thanks Link to comment Share on other sites More sharing options...
Dr4Film Posted June 21, 2022 Share Posted June 21, 2022 What brand of transfer switch do you have? Is there any writing on the cover as to the brand? My guess is that your relays are 120 VAC versus 12 VDC. Those relays will hum and sometimes be very annoying. The only way to eliminate the hum is to replace the entire transfer switch with one that uses 12 VDC relays. Link to comment Share on other sites More sharing options...
waterskier_1 Posted June 21, 2022 Share Posted June 21, 2022 That is not his transfer switch ... at leastit's not the Generator to Shore Power transfer switch Richard is likely thinking of. These relays (contractors) so make up a short of "transfer switch", but to transfer between the Inverter & Shore Power. Prior to the newer Inverter/Chargers, which now accomplish this function wholly within the unit, Monaco had to "make" that functionality. These are mostly AC relays, since what energizes them is the presence of 110VAC Shore Power. Without redesigning the whole circuitry, you'll have to stay with the same 110VAC relays. Sometimes, as relays get old, the cores do vibrate more causes the noise. New relays might reduce the noise. I don't know or a way to determine the part number without removal. Monaco never produced a Parts Manual down to that level. That whole box was custom made for (by) Monaco. - Rick N Link to comment Share on other sites More sharing options...
Garage Monster Posted June 21, 2022 Author Share Posted June 21, 2022 If I understand correctly the picture I included where the hundred twenty volt contactors are is the transfer switch. There is no writing anywhere other than the warning that it is high voltage. I don't see any practical way to replace this entire thing I just want to replace the two contactors that are humming. Any other ideas? Link to comment Share on other sites More sharing options...
Tom Cherry Posted June 21, 2022 Share Posted June 21, 2022 1 hour ago, Garage Monster said: When plugged into shore power two of these contactors produce quite an annoying hum or buzzing sound and they are above the bed. I can see no numbers on them. Can anybody tell me how to source new ones without removing one first? Ant help will be appreciated. The coach is a 93 Monaco. Thanks Hopefully some of the guys with more experience and have had older coaches will chime in. This is a new one on me and I have been moderating and highly engaged for over 13 years and have a good electrical background. I would go to IRV2 or do a google search. Richard's advice is correct for the ATS. The earlier ESCO models used 110 VAC coils and they hummed....depends on your hearing or your partner's hearing as to whether that is an issue. The newer BRD50LPT (memory) Esco is a 12 VDC relay and the coils do not provide backup for a vocalist.... @vanwill52 @Dave P Have you seen these? Link to comment Share on other sites More sharing options...
Garage Monster Posted June 21, 2022 Author Share Posted June 21, 2022 Thanks Rick. As I understand it these relays are energized when I plug into shore power. I was hoping somebody could tell me how to find matching contactors. Link to comment Share on other sites More sharing options...
Fasthobie16 Posted June 21, 2022 Share Posted June 21, 2022 Take a pic of one relay, label each wire to the terminals. Also make a drawing of it. Take the relay to a well stocked electrical supply (Grainger possibly) for them to do a matchup with the same amount of contacts and a 120vac coil. I would not think it would have to be rated over 30 amps. IMHO . It probably won’t look the same but hopefully you’ll be able to mount it in the same enclosure . 1 Link to comment Share on other sites More sharing options...
waterskier_1 Posted June 21, 2022 Share Posted June 21, 2022 3 hours ago, Garage Monster said: Thanks Rick. As I understand it these relays are energized when I plug into shore power. I was hoping somebody could tell me how to find matching contactors. I don't think that will be possible without removal. I think that 3 are the same, and the fourth is different, but it's been many years since I worked on that power box. I had one in my 97 Dynasty, but no longer have that coach. I think once removed, there may be markings on it you could Google, or that a large electrical supply house may be able to match. -Rick N. Link to comment Share on other sites More sharing options...
Garage Monster Posted June 21, 2022 Author Share Posted June 21, 2022 Fast Hobie and Rick. I will do as suggested and take one to the electrical supply. All 4 appear to be the same. Link to comment Share on other sites More sharing options...
Fasthobie16 Posted June 21, 2022 Share Posted June 21, 2022 Also you may just be able to just clean or file the contacts. They may be burnt a little bit. Hope that helps. Link to comment Share on other sites More sharing options...
BradHend Posted June 21, 2022 Share Posted June 21, 2022 Those are the same relays some older elevators use. Before you replace them, check to see if something has got stuck in, on or around the armature. Usually a tiny piece of metal or something gets stuck. Carefully remove the bottom spring and then work the relay face off to expose the armature. Give it a good look over, wipe the armature face and see if that stops your noise. Could just be a buildup of metal debris from normal use. Make sure you’re in a zero power condition! Use a meter!! Good luck. Link to comment Share on other sites More sharing options...
Garage Monster Posted June 21, 2022 Author Share Posted June 21, 2022 I pulled a contactor and there is a manufacturer and part number on it. I checked locally and ended up ordering 2 online to be here Friday. Still a valid part in in stock in several places. 1 minute ago, BradHend said: Those are the same relays some older elevators use. Before you replace them, check to see if something has got stuck in, on or around the armature. Usually a tiny piece of metal or something gets stuck. Carefully remove the bottom spring and then work the relay face off to expose the armature. Give it a good look over, wipe the armature face and see if that stops your noise. Could just be a buildup of metal debris from normal use. Make sure you’re in a zero power condition! Use a meter!! Good luck. That is good info but after 29 years I will just replace with same ones of the same part #. Link to comment Share on other sites More sharing options...
BradHend Posted June 21, 2022 Share Posted June 21, 2022 Potter Brumfield? Link to comment Share on other sites More sharing options...
Garage Monster Posted June 22, 2022 Author Share Posted June 22, 2022 1 hour ago, BradHend said: Potter Brumfield? Yes Potter Brumfield PRD-11AY0-120 From Allied Electric alliedelec.com Order by 10 pm eastern and they ship same day. Mine due here in CA Friday. Link to comment Share on other sites More sharing options...
Garage Monster Posted July 5, 2022 Author Share Posted July 5, 2022 The contactors received from Allied Electronics were exactly the same part. I easily replaced the two old contactors that were buzzing and now all is silent. You can Google Allied Electronics. There shipping was fast and there follow up was appreciated. 1 Link to comment Share on other sites More sharing options...
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