Cavalier cs-96 compressor resistance

[Faza]

Hi
I'm making a start on restoring my Cavalier CS 96, I've removed the cooling unit and have it mounted on a platform.
It was purchased not working and wireing was badly perished so hasn't run for a long time.
Testing the compressor resistance with an ohm meter shows common to start 15 ohms common to run winding is 2 ohms. Can I have confirmation on whether the compressor is good or bad? If I'm lookingfor a replacement compressor I'm located in Australia so may be a bit of a search finding a 110volt unit.
Would like to retain the condenser and evaporator as they do seem to be in good condition.
I intend to replace the dryer and both fans .
Picture of compressor info tag is attached.
Cheers
John

[Faza]

Bit of an update, this post by JohnieG seems to be similar , Compressor is a AP4111 Tecumseh 1/4hp.
http://soda-machines.com/discussions/index.php/topic,148.0.html
My 3in1 arrived today so I connected it and plugged it in, compressor kicked in straight away and the capillary tube where it enters the evaporator started to chill after about a minute.
Pretty happy that the original compressor works but the resistances are confusing me, should it be changed out whilst I have the cooling deck on the bench or are the resistances ok?
Cooling deck restore is pretty well stalled until I find out if compressor is ok.
Cheers
John

[johnieG]

Hello & welcome to the site John ...   You quoteing my old post from back in 2002 is making me feel dated!  ( of perhaps more experienced is a better way to think of it)

Well it's good that it cranked over & is chilling anyway,

as I've found out over the many years of doing this hobby, compressor start & Run winding resistances can vary a bit even between seemingly identical compressors of the same model & size/horsepower ( or BTU) ratings, so don't sweat it, if the compressor successfully turns over & runs you're 75% out of the wood so to speak, more importantly is the system charge & running  refrigerant (freon) pressures, of which in your case aren't going to be readily available to read due to the fact that your system is still as originally built with no external service ports visible to use to get a pressure reading out of anyway.  

JohnieG

[Faza]

Johnie thx for the confirmation that all is ok, I'll move on the restoring the deck.
How important is it to change the filter dryer? Is this normally done with these old machines.
Also I need to replace the evaporator and condenser fans, would like to source as much as I can locally in Australia to save on postage, can't seem to find a model/part number of the replacements.

[johnieG]

A good question, & here's a fun fact, your system doesn't have one       ( a filter-dryer)  Vendo didn't seem fit to install them on the majority of the refrigeration decks on these machines they had manufactured, they used a small ( you'd never even know it was there unless you knew what you were looking at) inline fine filter-screen ( some call it a sieve) it's the size and shape of a pencil eraser & inserted into the inner tubing at the tail-end of the condensing coils line right where it seems to change diameter & connect to the capillary tube.   

A new filter-dryer should always be installed when replacing an old compressor with a new unit, or when a sealed refrigeration system is opened for servicing such as a leak repair, etc., however since you aren't replacing your compressor, your service person would have to recover the old freon/R12 & cut open the service line at the high side where it exits the condensing coils & braze one inline, pull the system down to a high (deep) vacuum & recharge the system with the recycled R12 Freon or convert the system over to a more Enviro-frendly gas, ( I'd imagine that Old-stock or Virgin R12 is pricey if even still available down in Oz) it's not complicated to put one in, but it will cost you some coins...

the condensing fan motor is a standard "unit-bearing" type used in HVACR replacement & repair work, yours should be 120Volts AC/50-60Hz 1550 RPM, CW (clock-wise rotation as view from the shaft-end) if you cant find it locally, you might try online at your equivalent of Graingers supply company.  https://www.grainger.com/product/EM-S-Shaded-Pole-Unit-Bearing-Motor-5YJN9?internalSearchTerm=Shaded+Pole+Unit+Bearing+Motor%2C+9+Output+Watts%2C+1550+Nameplate+RPM%2C+115+Voltage%2C+Frame%3A+Non-Standard&suggestConfigId=8&searchBar=true

The evaporator motor is an enclosed "air-over" style 3.3 inch diameter case, single shaft such as a Dayton MODEL 3M538BG 120Vac/1550 Rpm, 1/4" shaft diameter,  such as Garingers model  ( view link)   https://www.grainger.com/product/DAYTON-1-70-HP-3M538?internalSearchTerm=1%2F70+HP%2C+HVAC+Motor%2C+Shaded+Pole%2C+1550+Nameplate+RPM%2C+115+Voltage%2C+Frame+3.3&suggestConfigId=8&searchBar=true     if you aren't sure of the rotation, you can get this motor type in a convertible model, it reverses it rotation by you removing the end-plated & flipping over the armature-shaft core & reassembling the end-plates.  check online for the correct application.

[Faza]

Thx for all the good information Johnie, strange the manual shows a filter dryer I wrongly assumed it was the copper cylinder strapped to the evaporator.
Struggling to find 110volt motors suitable in Australia so I'll look at buying from the site sponsors hope postage isn't a killer.

[johnieG]

The copper cylinder attached to the evaporator is an Accumulator, not a filter/dryer, you normally find the filter/dryer ( which as it name suggests is a water absorbing desiccant media filled copper tube or steel cylinder which also contains a micro-filer screen, or some cheaper models use a perforated screen & glass wool to catch debris)  these are normally located on the "high" side of the system, again typically at the exit port/tube of the condenser coil/radiator assembly were it filters the high-pressure liquid freon to help remove any water vapor that has migrated into the system & prevent it ( the water) from freezing at the tip of the capillary tube & plugging it with Ice crystals & causing an internal blockage,.

They do make suction return line filters/dryers for the low-pressure (vapor) return line, but these aren't normally seen on these smaller vending machines, the low side filter/dryers are more common in automotive AC systems & building HVAC units

an Accumulator is designed to help prevent any still-liquid freon from making its way back to the compressor ( it helps the freon to "boil off" & return to a vapor state) where it could damage the suction valve or piston, it's pretty obvious when this occurred because the large suction line leaving the evaporator & heading down back to the compressor will frost up outside of the bottle compartment down under near the compressor deck. this can be caused by an over-charge system, or a failed or jammed evaporator fan (no air-flow causes the freon not to evaporate completely & it ices up the evap' coils)

The Grainger supply company does ship to Australia, however you'd need to set up an account with them first, they normally don't sell to the general public, more so to companies & contractors, it depends if what your buying has restrictions, I cant imagine electric motors fall into a restricted class, say like cleaning fluids, etc. doesnt hurt to inquire via email to them. 

( I use my job/work account to get me past the bouncer at the door  )
                                                                                                                       

[Faza]

With what I thought was a good working compressor I went ahead with a restore of the cooling deck, rewired it new evaporator and condenser fan as well as a new thermostat.
Started ok with frosting where capillary enters evaporator, have since found out that compressor is sometimes drawing 3 amps and sometimes 10 amps.
Any ideas or is compressor dead.

[johnieG]

don't panic just yet...your compressor may be normal.

the compressor you are using has  a split-wound motor,  internally it has two separate electrical windings, when the compressor is first called to run, the ( appropriately named) start-run relay will first apply current to the "Start" winding, it has a high torque to start the motor spinning against the pressure of the freon in the system, and thus be seen with a higher current draw from the line, now once the motor gets up to speed ( .5-1seconds) the current it draws will cause the Start-run relay to "drop out" the "start" winding & engage the "Run" winding, which will now continue to spin the motor at it's design speed but with a greatly reduced current draw.  the compressor will now run at the lower current draw until the thermostat drops it out when it gets to the cold set-point inside the beverage area until it gets warm enough again to call the compressor to start, and the cycle will repeat.

so when the compressor first turns "ON"  you will see a high current draw momentarily, then it should drop down to its normal "Running" amps, the "START" current reading / difference can be anywhere between 2-10 times greater than the "RUN" current.

however if you have a problem with your start-run relay unit ( loose connection, worn or sticky/tight compressor, an over-charged system with too much back-pressure, or an over-heated system again with too much back-pressure, your relay or your over-current safety device ( some call it the "Clicket" will cause the compressor to attempt to start or re-start over & over again,  this can damage the start-winding & burn it open & then the compressor will be dead ( being that it's unable to start let alone run.  3- amps is around normal running current for a 1/5 HP compressor, yours should have about a 1/4 HP unit & should draw a bit more while running.    but 10 then 3 amps ( start vs run current) doesnt sound that bad to me.

a loose connection, or a damaged start-run relay ( or an oversized replacement start-run like a 3-in-1 booster by supco) can cause many headaches,   using a 1/2 HP unit on a 1/4 HP motor will cause the "start" circuit to not drop-out & cause the motor to "studder"  ( slap itself on & off rapidly)   if you've reused the original start-run relay as I suspect, it may have worn contact points & cause troubles when starting or dropping out once it is supposed to be in the "run" mode... I would replace it with an external 3-in1 unit from Supco ( or similar) they sell one for 1/4 HP/220 Vac


but if the system is running normally & the higher amp draw is only when it first starts, then drops to the lower reading, this is normal

the cooling deck looks great by the way...

[Faza]

Johnie thanks for the reply, I have already installed a 3 in 1 relay as the existing one was trashed.
I might see if I can devise a method of removing the start winding from the circuit when the compressor is up and running to check your theory. (I'm a electrician no refrigeration knowledge though)
I'm using a 240v to 115v step down transformer so have used a 1/3 to 1/4hp 115v 3 in 1 .
Have the 3 in 1 relays been known to be faulty in the past not removing the start winding?
The system seems to start cooling immediately once the compressor kicks in, compressor looks original with no ports to check pressures so I'd assume it hasn't been overcharged, I haven't noticed tell tale signs of a leak but I guess it could be undercharged.
Cheers
John