Motor Overload Protector - Function Test..

Here's the email from Supco :

BTW, I'm running an RO81 in my CA form A. I also had the RO overload trip once before I did the capillary conversion which I think is why I emailed Supco in the first place.



The overload protector in a URO81 has a steady state RLA [run load amps]
of 4 amps.
This means that the UTC [ultimate trip current] is 4 amps. If the
continuous draw amps exceeds 4 amps the URO81 will trip in about 15
seconds at a 70 degrees.
The LRA [locked rotor amps] protection is 12 amps, this will trip in
about 2 seconds. The URO81 is a PTC device and runs hot to the touch as
all PTC relays do.

The step down transformer I run my CA-2 off has a 5A thermal circuit breaker on the 240V primary side to protect the transformer windings, not so much the fridge. However, it will trip well before the overload protection in the fridge is activated. If a CA doesn't start up within about 2 seconds, it's never going to start, and there's a definite problem that needs attending to.

The CA-2 needs to be purged at least twice a year, always after a few weeks of hot weather in summer when the room temperature has been 25-35C. With the capillary tube it will continue to run with good cycling times and have plenty of cooling capacity, even when the NCG's have built up to the point where only the top section of the condenser tubing is still warm (one sixth of the condenser capacity?). So, I can get a bit slack about purging it when I should...but then I get caught out; the frost line finally drops within a couple of days, etc.
The CA-1 requires it a lot less frequently. Its behaviour is quite different to the CA-2 and it's the start of compressor rattling and shorter off times that motivates me to purge it. The CA-1 has never had the oil slug in the evaporator issue that occurs with the CA-2 every winter or two.

From my CA-2 log book since the evaporator transplant (25th March 2016):
28th May 2016 - Rattling and contracting frost. Start of cold weather. Purging made no diff. Restart from warm & OK (oil slug).
29th Dec 2016 - Timed out. 29C in kitchen. 1/2 condenser had NCG. Purged until warmth almost at float valve.
4th March 2017 - Purge. Several weeks of 30C room temp in Jan/Feb. Power up to 232W & over 10 min run times [normally 2.5 to 4 mins].
1st July 2017 - Rattling since cold weather. Stalled. Many attempts to restart. Purged, although did not need it. Oil slug in evap. 200-300W power draw. Tilted top to get oil from bottom of evap. Power consumption dropped as this was done.
28th Dec 2017 - Purge. Stall on start up. Increased power consumption noticed a few days ago.
9th March 2018 - Purge. Took about an hour. Constant rattling and start up rattles for about a week.
19th May 2018 - Purge. Constant rattling. Kitchen temp 13C. Two start up stalls in previous weeks.

I don't want to give the idea the CA-2 is a bad design from that. It's just that's what happens when someone breaks a refrigerant line and leaves it open to the atmosphere for a few years.
On the other hand, looking at the CA-1 it requires a lot less maintenance. It lives in my computer room, so I'm subconsciously aware of anything happening to its cycling times, being next to it several hours a day.

11th Nov 2013 - charge finalised and put into use.
12th April 2015 - Purge. Rattling and low frost
11th Dec 2015 - Purge. Running well but 1/2 condenser warm.
5th July 2016 - Purge. Low frost after defrosting, only 10 mins off time. 4 x 3 minute purges required.
21st March 2017 - Purge. Cycle times 9 mins off, 4 mins on. Low frost. Not rattling. [off time should typically be 16 mins]
3rd May 2018 - Purge. Low frost, rattling slightly.

Keep in mind, besides moisture, methyl formate also breaks down at high temperatures over time.

My CA-2-A16 has never needed to be bled since 2015. It shows no sign of issues either, condenser still gets warm all the way to the bottom.
But I keep my kitchen cool all year, though it did get into the low 80s for about a week in 2017. Besides that, it's usually in the high 60s in there, low 70s at the warmest.

From what I've been able to work out, they were only sold in the eastern states. Also, in the 1930's only the cities and large towns had reticulated electricity. If you like kerosene fridges, Australia is the place to be because they seem to be quite prolific in comparison. Having said that, it doesn't explain the lack of monitor tops today in the areas that did have AGE dealers.
Something seemed to change around the late 1990's - it was suddenly fashionable to get rid of anything old. I don't know if the home renovation shows that started to appear on TV at the time had anything to do with it, but it is very rare to see an original kitchen or bathroom in an old house now. Back in the 1970's, most suburban shopping strips had a second hand/junk store, and no doubt there would have been quite a few MT's to be had then. These have all gone now because the modern generation only buys new disposable furniture and appliances. Second hand shops now exist in the form of selling "retro" because it's in vogue...and charge accordingly. But you won't find an old fridge or black and white TV in such a place any more; just coloured plastic things like lamps and picnic sets from the 60's and 70's instead.
In my years of patrolling council clean ups (where everyone puts their junk out on the nature strip for collection) I have never seen a MT put out. I'd guess they were all privately dumped, or traded in (and then dumped). Australian houses don't have below ground basements like in the U.S., so if something isn't wanted it tends to get disposed of quickly rather than just being put out of sight out of mind.

trove.nla.gov.au/newspaper/article/17210464?searchTerm=general electric monitor top &searchLimits=l-availability=y|||l-australian=y|||l-category=