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Old 27th Jun 2017, 4:21 pm   #21
mark_in_manc
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Default Re: Fridge compressor capacitors

Ebay has a number of suppliers of rubber strip used for boat and caravan windows - might be worth a look. Also I think Frosts Auto Restoration in Rochdale stock this kind of thing, including generic door seals for old cars which comprise an extrusion of a kind of rubber balloon profile, mounted on a rubber claw with a steel stiffener inside which crimps onto a welded seam. It may be that your fridge uses something similar, and you find something you can use from the profiles available.

cheers
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Old 2nd Jul 2017, 6:21 pm   #22
PsychMan
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I fear my efforts might be in vain. I hadn't run the fridge for a week or two and today switched it on - the compressor failed to start and overload clicked off. I waited a while and tried again, eventually the forth time it did start, and has cycled on and off fine since.

Is there a reason a fridge that hasn't run for a while won't start? Or is it likely my compressor is going?

If there's no logical reason other than beginnings of compressor failure, I might have to say goodbye to it, shame after so much time spent on it
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Old 3rd Jul 2017, 7:02 am   #23
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Default Re: Fridge compressor capacitors

Unlikely to be a compressor fault after all these years. I suspect a poor connection somewhere; check that the connections on the compressor are good and elsewhere in your new starting system. Electrically all there is in those motors is two windings, and they are in a sealed environment, so unless a winding has been cooked by excess current, failure is not very likely. If a winding had been poorly wound, I think it is likely to have failed before now; that unit is nearly 60 years old. I suppose the compressor itself must wear out eventually, I don't know what sort of device is in there.
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Old 3rd Jul 2017, 8:32 am   #24
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I'll check the connections. For the most part, any connections in my new starting system are either with choc blocks, or soldered and heat shrunk over. I made sure all the choc block connections were strong, but worth checking all the same.

The compressor screw connections themselves originally had connectors like crimp rings on the old wiring, but just the circular part. I couldn't see a way to reuse them, and I couldn't find modern crimp rings that would fit. In the end I twisted the wire strands together and wound them round a similar diameter drill bit to make a loop, put this on the screw terminals and tightened the connectors over them. I gave them a tug to make sure they were held firmly. If there is any connection problem it could be here I suppose. It was the only part of the rewire I wasn't 100% happy with. I might revisit this and try looping the wire round a suitable washer.

I did also wonder if my solid state relay was to blame, but it was passing 246v AC just fine during a failed start.

Im sure the compressor windings are fine, I just wonder if something mechanical is going on in the compressor to create difficult starting conditions. Its fairly noisy running compared to modern fridge compressors, which I assume is wear, but I know very little about compressors.
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Old 3rd Jul 2017, 2:19 pm   #25
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Forgot to add, this did happen a few times before on the old starter, and I put it down to a problem with that starter circuit. Like yesterday, Once it started it would run and cycle on off fine.
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Old 3rd Jul 2017, 7:35 pm   #26
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Default Re: Fridge compressor capacitors

Tried again tonight, started first time. Tested all connections, firm and solid as anything..

I did hear something about if a compressor has just started and powered off a few seconds later, it can be tough to restart, not sure if that applies over a period of days. I suppose these things are meant to run 24/7 anyway, rather than the short times Im running this to test it.

I think I'll bite the bullet and redo the seal anyway and see how it fares when left on.
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Old 3rd Jul 2017, 8:38 pm   #27
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If a fridge compressor is switched off, then a few seconds later is switched back on it may struggle to start, because there will still be pressure to start against from when it was running the previous time, but once it has been off for a minute of so the pressures should have equalised and starting should be OK. That compressor has always been audible, far louder than modern ones, so I wouldn't panic on that score alone
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Old 4th Jul 2017, 6:46 am   #28
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I've had at least one fridge before which struggled to start when taken out of storage. After a few minutes of frequent cutting in and out, it got going and ran perfectly thereafter.
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Old 7th Jul 2017, 10:57 am   #29
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That's good to know guys.

I found some perfect door seal material on ebay in the USA and have placed an order. Luckily my mums out there visiting family and is going to bring it back for me to save shipping and customs charges.

I looked at all sorts available here, and nothing else seems to match the profile and thickness the way this does. Like a lot of things in retail, you get so much choice in America.

Hopefully I'll have that done by next week and can keep the machine running to see how it fares. I'm a lot more confident in it now.

One of the mounts is still working loose somehow and making excessive noise, but Im sure I can wedge some rubber in the fitting or glue the clip in place. When its just right you don't hear it very much at all. When its rattling its like a noisy power tool!
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Old 14th Jul 2017, 11:41 am   #30
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Door seal is done, not an easy job cutting the mitre sections given the poor instructions, but I think its a decent enough improvement over the old one. It does bind a little on the hinge side, but after trying shims on the door hinges I found it was either a case of compromising the seal or it binding a little. I might try something like Vaseline here to ease wear on it. The door needs a little push to release the handle, I might play around with the door catch to try and improve this.

The cycle time is much improved and on a test with an empty fridge, once cool would cycle on for 9 mins, then off for 19 mins or so. Considering my thermostat readings might need a little tweaking, Im quite happy with this as previous tests it would run more often than not. I think having items in the fridge will also help it retain its cool.

The only issue left is the compressor mount on the left side continually works loose and rattles like mad. They sit on springs with this model. I had adjusted the nuts at the bottom on each side once level, and threadlocked them to stop them moving. But Its the clip at the top that rattles loose, it seems to screw onto the thread of the bolt, and if I tighten by hand it will run very quiet for a while, but then slacken off and the noise is back.

I don't have the best pictures at the moment, but I edited some from my phone if anyone is familiar with this fitting type. There is a rubber cap on top of the bolt above the said clip, which doesn't seem to be doing anything right now, perhaps this could have helped stop the clip rattling loose?

Im considering adjusting the clip and then gluing it in place, or wedging some rubber there to stop it moving, but would rather ask some opinions before trying anything permanent

The pictures aren't necessarily the side with the problem, just here to try and show what the mounts are like. I can take better ones if that's any help.
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Old 14th Jul 2017, 3:40 pm   #31
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Default Re: Fridge compressor capacitors

That clip looks like a form of "Spire nut" - is the spindle that sticks through into the rubber cap threaded, or does it just have a slot or step machined into it for the outer part of the springy clip to engage with?

Easy bodge - drill a small hole transversely through the spindle at the right place and put a roll-pin through it?
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Old 21st Jul 2017, 10:03 am   #32
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Default Re: Fridge compressor capacitors

Sorry its took a while to come back to this. I've attached a better picture of the fixing, it is plain and not threaded past a certain point.

On closer inspection there seemed to be a lot more play in this mount than the other one, so I think when I adjusted it last time I might have missed the point slightly. I re-adjusted so they both had a comparable amount of spring visible and similar movement, and touch wood its been very quiet since and doesn't appear to be rattling loose - so far!
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Old 21st Jul 2017, 10:28 am   #33
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Default Re: Fridge compressor capacitors

Also, I think I have found the cause of my starting problems, which have come back to haunt.

After finding the compressor would repeatedly not start again, I tried bypassing the solid state relay and it started no problem. Strangely upon reconnecting the relay a few minutes later it continued to function. I've observed this behaviour twice now. Without doubt the relay isn't up to the job, after doing some reading online it would appear the market is flooded with fake versions of this relay (Fotek SSR 25da). But I also notice this is a "zero-crossing" relay in its genuine form, and therefore not suited to inductive loads to start with, despite what the sheet said the seller provided. I think I need to invest a little in a decent SSR, possibly from a more reputable firm like Crydom for example, and possibly consider adding a varistor across its contacts.

If anyone has any recommendations that would be very useful as I'm new to this area. I wonder if a varistor would be needed to deal with voltage spikes at switch off, if I sized the relay for considerably higher voltage to begin with. The current relay is allegedly capable of delivering 25A at 380v
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Old 21st Jul 2017, 11:12 am   #34
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Default Re: Fridge compressor capacitors

If you haven't yet found a good replacement door seal I wonder if this would be suitable?

http://www.woolies-trim.co.uk/p-1798...extrusion.aspx

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Old 21st Jul 2017, 12:14 pm   #35
PsychMan
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Default Re: Fridge compressor capacitors

Yes thanks Peter I did manage to replace it. The link you sent looks like it would also do the job, I'll try and remember it in case this doesn't hold up.
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Old 22nd Jul 2017, 4:23 pm   #36
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I'm considering a 10A mechanical relay with RC snubber across the contacts, and a bi directional TVS diode across the supply (250v) version to deal with the spikes on switch off. Might this be sufficient or should I look for better solid state relays?
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