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Author Topic: Strong Power Supply Problems!!! Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 08-19-2006 06:16 PM                        quote: Steve Guttag Sorry, Jack you are wrong on that one...there is no significant current on the contacts of the contactor until the lamp ignites. Steve, OK... I'll bite. How could the contactor cause a loud buzzing sound? The only way I could see this is if the plunger doesn't seat properly... and that would be purely mechanical. I have one on my reader board that got a bit rusty last year... it buzzed like Hell until I took it apart & cleaned the rust out. If that were the case for Steve, his would probably be buzzing as soon as he turned on the power supply. He says the buzzing starts when he ignites the bulb. That would tend to eliminate the contactor in my mind, unless he has an incoming voltage drop issue. Steve says his current is fine, and he hasn't suggested his booth lights drop when he ignites the lamp... so I'm assuming his incoming voltage is probably OK. I can't see how the contacts themselves could buzz.... with current or not, it's just a switch. Maybe an arcing sound, as they're welding themselves together... but not a prolonged buzz. I initially went with the fan, because Steve said his buzz sounded like a siren. That would infer a changing frequency. The only thing in there that could do that would be the fan. Now that he says the buzz starts when he ignites the bulb, it seems more likely that it's just the laminations in his transformer... which is common in those old supplies. If not... what am I missing????  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 08-19-2006 08:48 PM                     If it is just a buzz the it is just transformer noise...though it would tend to transistion between a hum (normal) to buzz (vibrations on the coils). As for the contactor...think about a pitted contact that is having humid air pumped upon it...when the lamp ignites, you have one or more contacts that is worn and has humidity in it...you could litterally be buring that off each time it cycles. But beyond that...when the contacts pit, their contact quality diminishes...though may not be in total failure. Many a contactor has burned completely up without giving any indication from the picture point of view until the damage is done. We always make a point of inspecting the wires going into/out of a contactor as well as ensuring that the connnections are tight...sometimes the only clue you have is a discoloration of a wire feeding the contactor. Another thing that one could try to isolate the contactor without completely removing it is to try one leg at a time bypassing the contactor (make sure the power is off when you do this...just move one of the line side wires to the load side...if the problem persists, try the other side and restore the first side you chose.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-19-2006 08:58 PM                     I havce had the steel cores of contactors corrode and then they can't completely pull closed... causing a really loud buzz....110 db or so and alot louder than a power transfromer buzz. Mainly had this happen on Irems but any contactor with a laminated steel core contactor(most all of them)could have this happen. Mark  |  IP: Logged Steve Wilson Expert Film Handler Posts: 109 From: Paoli, IN, USA Registered: May 2004 posted 08-20-2006 01:11 AM                        We were on the screen to tonight and stayed on. Contacts started out loud, and quieted down to near nothing with in 15 minutes or so. My Buddy, Jim Boyd of Ohio, just happend to be in St Louis today is going to try to stop by and see me Sunday on his way home. He is staying the night with in a couple hours of me He should be able to figure it out. He also thinks its the contacts. We will see how things go on Sunday and report back. Thanks to all that have posted.  |  IP: Logged Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 08-20-2006 01:50 AM                        Almost sounds like there's a temperature factor there. It'll be interesting to hear what Jim comes up with. He's helped Steve through a couple of past booth challenges.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 08-20-2006 02:09 AM                        I say, hit it with a stick. This sound sounds mechanical. If you were to push some stuff around in there, put pressure on the relay and the fan mounting, even moving around the wires close to the contact terminal you could determine where the noise is coming from, maybe even stopping it. On one of ours, all we had to do was push on one of the side panels and the loud rattling noise it was making stopped dead -- a few tightened screws fixed it. Even the coils themselves and the steel cabinate -- if there is vibration there, putting a different physical pressure would make the sound change. The fact that nothing untoward is going on electrically with the bulb, current, light, etc., tends to rule out some weird electrical problem. That screaming siren sound has got to be viration of some sort. Be interesting to see what. And Steve, at least it is keeping your picture on the screen...you are lucky; one of ours didn't make any unusual noise to give any warning -- it just burst into flames in the middle of a show last year!  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 08-20-2006 03:46 AM                     Wonder if just take the contactor out, take an emery board and dress up the contacts some to see if this would be a quick fix until the new contactor is replaced...like dressing up dist. points in a car.  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 08-20-2006 12:30 PM                       quote: My Buddy, Jim Boyd of Ohio... is going to try to stop by Jim Boyd is everyone's friend. He's a good man.  |  IP: Logged Steve Wilson Expert Film Handler Posts: 109 From: Paoli, IN, USA Registered: May 2004 posted 08-21-2006 12:32 AM                        Jim Boyd made his stop by as promised and low an behold, the bottom contactor was burned up pretty bad. He dressed it up a bit and tommarow I will look for a new contactor block. Jim, said he may have spare one out of a old box he would check on and mail it too me. I got kind of Lucky this time as the contactor block is easily installed by myself. I really appreciate eveyones input and opinions on this matter. Thank you for taking your time to respond!  |  IP: Logged Steve Wilson Expert Film Handler Posts: 109 From: Paoli, IN, USA Registered: May 2004 posted 08-21-2006 03:18 PM                        Well, I thought I was out of the woods, but I am not. I put in the new contactor today and I still have a loud Hum. There is no doubt the the contactor was burnt, I saw it will my own eyes! However, I now feel the additional hum is coming from either of the 2 giant transformers. Jim is looking to see if he might have part of an old Strong Power Supplys! The sound is fairly loud, but not deafening! I have exactly 35 more hours of playtime before I close for the season. We are looking at puting in a larger lamphouse later this fall or early next spring. Does anyone have a best guess as to how long or how short of a time it might be before this units quits all together. Best Guess anyone!  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-21-2006 04:40 PM                     If it is just the windings vibrating or the laminations which is more likely it will probably go on for years The failure will occur when the varnish of the windings breaks and creates a "current leakage fault" If one was very worried one could get a motor shop to do a high pot test of the transformer to test the condition of the insulation  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 08-21-2006 07:02 PM                        Steve; have fought many many of those Strongs! Borrow a good set of socket wrenches with extenders, have it all ready to go correctly sized. Run all night; turn off the power at the breaker panel, and then while still hot, tighten the laminations on all of the large transformers, (one is a choke). You may get 4 or more turns. It is important that the temperature still be hot when you do this. As stated above, hum will go on forever with no faults. I would NOT replace components; just tighten the ones you have. Louis  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-21-2006 07:25 PM                     I typically have carefully pounded oak wedges between the windings and the laminations to cure this problem. usually you can get rid of all of it but at least you can always make it quieter. Have also done this on humming Christies many times. Only use OAK since it is a stable wood. The part that is making the loud humm is the entore core or winding section of the transformer. Its come loose fomr the iron frame and is free to move aroound in there. I generally carefully do this with the power on and the thing humming away as you can then carefully find the point that its the quietest... just don't get carried away with those wedges. One or two is all it takes to quiet one down. Mark  |  IP: Logged Steve Wilson Expert Film Handler Posts: 109 From: Paoli, IN, USA Registered: May 2004 posted 08-26-2006 09:27 AM                        quote: From Louis: Steve: would bet on the contactor contacts singing due to moisture. It's been very high humidity in our area,lately. Louis Hi All, I had been working on taking the advice Louis gave me last week to tighten the bolts in the tranformers. I opened the case, the bolts through the transformers were rusted some what. Put WD-40 on all Bolt heads and nuts... Set for 2 days, I went to turn the Bulb on last night for the movie. Not a single Noise was uttered by this machine. Unless WD-40 was somewhat of a wonder cure, I would think that maybe with the Very High Humidity that Louis was talking about the last 2 weekends may have been the culprit. He may have the correct answer, Only time will tell and another rise in severe humidity here in Indiana. Knock on Wood!!! Of course, the time to have High Heat and Humidity here in Indiana are quickly passing for the season.  |  IP: Logged System Notices Forum Watchdog / Soup Nazi Posts: 215 Registered: Apr 2004 posted 11-16-2007 01:23 AM                 It has been 446 days since the last post.  |  IP: Logged

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