View Full Version : Start capacitor needed?
Hi,
Picked up an Embraco FF 6 BK compressor in hard rubbish and it didn't have a start capacitor with it. It's a 1/5HP unit from what I can determine from the Embraco site and trying to determine what I need for a start capacitor, as there isn't much info that I can find relating to that.
However I came across thread (http://www.xtremesystems.org/forums/showthread.php?p=1401880) and Ratax asked the question of wether or not his compressor needed a start run cap. Never got answered so I was wondering if it had one at all (and if I need one).
I understand why my old 1HP unit ripped from an aircon needed it, but this was from a fridge and it's relatively low powered.
Thanks heaps.
---dens
n00b 0f l337
09-18-2006, 06:00 AM
1/5hp is probably RSIR or RSCR.
Therefore most likely no start cap, a start cap will help though with starting torque. I suggest buying a 3 n' 1 start rated for 1/5hp or so, this is a good solution and may be cheaper than relays or caps.
Understandably that's why larger ones definitely need the start cap :)
Anyway had a look into what you're describing (hadn't heard of it before) and came up with this (http://reviews.ebay.com/Whirlpool-Refrigerator-Start-Relay_W0QQugidZ10000000000207460?ssPageName=BUYGD: CAT:-1:LISTINGS:4). Looks ideal, but if I can't get one from my local refrig places then i'll either give it a go without a cap or look for a cap for this one. However I have no idea what cap I should get (in terms of rating).
I found another forum post elsewhere with technical specs of a compressor in the same series as mine. here (http://www.techzonept.com/archive/index.php/t-68921.html) is the thread, and that one states that the motor is RSIR-CSIR, so could I safely assume this would be the same in my case?
Cheers,
---dens
_HL4E_HalfLife_
09-19-2006, 12:06 PM
Id just go with a 20 or 25uf 270+ volt run cap thats all it would need.
When I was down at heatcraft (http://lovelocks.com.au/) talking to one of the guys there, he said that it should be within 10% of the rated spec for the compressor. Now working with cap ratings is all a little new to me still so I'm kinda relying on anything given to me here.
Thanks though, will give heatcraft a call and see what they can quote me for one.
---dens
SexyMF
09-20-2006, 02:57 AM
Technical specs from their website says 20uF
http://www.embraco.com.br/portugue/produtos/02003.pdf (page13)
Oh my. I actually have that PDF on my HDD and I missed it. Thank you for taking the time to research it for me. I feel like a damn fool :P
Thanks to all of you for helping :)
---dens
wdrzal
09-20-2006, 05:10 AM
what voltage in your country? the replacment cap should be right on as far as uf or microfarad,they mean the same. But within 10% is allowable.the voltage rating should be above peak voltage not your rms voltage(root mean square)thats what your multimeter reads . for 120 voltrms thats 170v peak or higher for 240rms volt thats thats 340vpeak or higher is ok..
a higher voltage than needed on a cap is ok ,just the cap is a little more expensive as the voltage rating increases.
A rms voltage is a measurment of voltage/time depending on where you are you either have 50 or 60 cycle or htz voltage. in the usa 120v has a sine wave that has 170v peaks but since its alternating current it also has 170v valleys and each cycle (60 per second for 60 htz or cycle )the voltage must past 0, so the average is 120vrms.
but thats the reason why the cap voltage must be higher than the voltage your multimeter reads.
You can rest easy knowing I do know that μF means Microfarads :)
Australia is 240v/50Hz. So getting a cap that's 20μF and rated 340v and above will suit me fine?
Thanks,
---dens
wdrzal
09-20-2006, 07:15 AM
:up: :up: :up: :)
Cool. Might head down tomorrow and pick one up. Dunno where i'd be if it weren't for this place :lol:
---dens
SexyMF
09-20-2006, 12:46 PM
A rms voltage is a measurment of voltage/time depending on where you are you either have 50 or 60 cycle or htz voltage. in the usa 120v has a sine wave that has 170v peaks but since its alternating current it also has 170v valleys and each cycle (1 per second for 60 htz or cycle )the voltage must past 0, so the average is 120vrms.
To clarify:
The RMS voltage is the equivalent DC heating effect.
The relationship for single phase Vrms = Vpk/sqrt(2).
The average of any sinusoidal wave is 0.
50Hz means one cycle in 1/50second.
The motor run/start capacitors will be rated at 400V or higher.
wdrzal
09-20-2006, 01:33 PM
Thanks for pointing that out .I edited my post I had 1 .....shoud have been 60 per hz or cycle .
I should proof read .......I know that.:fact: :D
I picked up the cap today after work. I walked home with a 20μF 440V cap as well as some random bits to keep me occupied with brazing my second system up.
http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/th_DSCN0177Large.jpg (http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/DSCN0177Large.jpg)
Will need to figure out which terminals to wire to with the embraco unit and this, so will start to do some searching.
Thanks again guys.
---dens
wdrzal
09-21-2006, 07:05 AM
start or run their is a differance? iirc did someone tell you run,don't have time now will re-read thread latter.
SexyMF
09-21-2006, 12:20 PM
start or run their is a differance? iirc did someone tell you run,don't have time now will re-read thread latter.
Start caps can not be used as run caps. They are not rated for continuous use.
Can you give use a photo of the compressor electrical terminals? ie has it got a relay, thermal cutout etc
Here's a pic of the terminals.
http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/th_DSCN0179Large.jpg (http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/DSCN0179Large.jpg)
Just realised, what I got was a run cap. So by what you said i'm guessing that because it's actually rated for continuous use rather than just startup that I won't have a problem, correct?
Thanks for tolerating my questions still :)
---dens
wdrzal
09-21-2006, 07:15 PM
please give more compressor info , that has a relay on it indicating a start cap or may possibly need both . start cap MUST be dropped out of circuit after only 1 to 2 sec. you can not interchange start and run.
need to determine compressor type, capacitor start,capacitor run (CSCR) needs both types of caps. or capacitor start , induction run(CSIR) needs just start cap
I don't think thats 1/5 hp
Well all the info I can give is in the #6 post by SexyMF. That PDF's closest match to mine (FF 6 BK) is the FF 6HBK.
The compressor there shows that it doesn't require a run cap but does need a 270-324uF start cap.
I wasn't actually aware that there was a difference between a start and a run cap but it does make sense. Stupid me for jumping into it without fully understanding this.
In this PDF (http://www.embraco.com.br/portugue/produtos/533.pdf) it shows what the model numbers denote:
F: Basic Family
F: Electrical type - Relay/External connector/start cap or without start cap
: Nothing: standard efficiency
6: Compressor displacement
: Nothing: R12 (H means r134a - the only dif between that other version)
B: HBP, LBP/HD
K: LST (starting characteristic)
: Nothing: without oil cooler
I'm pretty much thinking that i've got two options. Since this thing doesn't seem to need a run cap, I can either accept it and see this as a lesson to research before buying a run cap for such an underpowered compressor, or return it for the cap that I need.
Edit: Looked into this (http://rc.danfoss.com/TechnicalInfo/literature/manuals/06/application_cz80c202.pdf#search=%22compressor%20te rms%20%20LST%20start%22) danfoss tech document and found out what LST stands for (Low starting torque). I guess this either means a less powerful cap is needed or none at all. I'm guessing I can't find my exact version because R12 has been well superceded, right?
Also, do you think this is more or less than 1/5hp?
---dens
wdrzal
09-21-2006, 08:14 PM
start caps will have a much higher uf than a run cap. run caps are "wet" caps usually in a silver metal can and weigh more than a "dry" start capacitor which are usually black in a bakelite or plactic container........not sure what the outer material is any more.
quote
Well all the info I can give is in the #6 post by SexyMF. That PDF's closest match to mine (FF 6 BK) is the FF 6HBK
close only count in horseshoes.
maybee the picture ,but looked bigger than 1/5hp and usually 1/5hp don't use start caps.
I know I have a run cap. I didn't understand when I did this that there was a difference between a start and a run cap. Now I do. The only thing I do actually need to know is wether or not I do need a start cap, and since it seems that I probably do, will I just need to go for a 270-324uF start cap now?
What I don't get is that if a start cap is what I needed (title of this thread), why was such a low microfarad capacitor suggested? Since anything that low seems to be specifically for use for run caps rather than start caps...
close only count in horseshoes.
I have no idea what you mean.
---dens
http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/th_EmbracoFull.jpg (http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/EmbracoFull.jpg) http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/th_EmbracoTag.jpg (http://img.photobucket.com/albums/v234/Anode/DeNsicles/Embraco/EmbracoTag.jpg)
Some pictures of the unit before it was taken out of the fridge.
---dens
wdrzal
09-21-2006, 09:36 PM
I know I have a run cap. I didn't understand when I did this that there was a difference between a start and a run cap. Now I do. The only thing I do actually need to know is wether or not I do need a start cap, and since it seems that I probably do, will I just need to go for a 270-324uF start cap now?
What I don't get is that if a start cap is what I needed (title of this thread), why was such a low microfarad capacitor suggested? Since anything that low seems to be specifically for use for run caps rather than start caps...
I have no idea what you mean.
---dens
horseshoes is game where you throw a "horseshoe" at a steel post and get points for a "ringer" around the post but get point also for being close. Thus we have a american expression close only count in horseshoes and handgernades.
as to the second part you said you had a 1/5 compressor and I am asumeing sexy responded on that info. with out elobrating it was a run cap.and from that point forward I also went by that asumtion.
now we have a pic we can clearly see a relay which would indicate a start cap. at least.
just 1 letter in a compressor nonclamature can mean so much ,not to even mention that manfactures have changed there nonclamature in certian companies.
Not using that companies compressors I,m not familiar with their model numbers.
wdrzal
09-21-2006, 09:55 PM
That relay just drops out the start windings and probably dos not use a cap if 1/5 and out of a fridge.
sorry for the miss understanding.
SexyMF
09-21-2006, 11:24 PM
I'm sorry. I made a mistake.
The FF 6BK 240V version is listed as RSIR CSIR. With a starting capacitor of 88-108uF. The electrics show a 'short relay' ( according to http://www.embraco.com.br/portugue/produtos/05005.pdf )
Reading also this http://www.embraco.com.br/portugue/produtos/533.pdf
tells me that the starting capacitor is optional. My guess is the starting torque is reduced.
So, it would appear that you can simply put power onto it now and it will run.
If it doen't need one I have NFI what i'm gonna do with a $25 capacitor :( I can't exchange it for anything else if I don't need it. Sht.. I might be able to get a store credit for it but I won't know til monday since they aren't open on the weekend.
Might give me some time to start it up and see.
I've heard of people suggesting testing compressors without lines connnected but i've never really been sure. Is there any risk in harming the compressor if I start the compressor up on its own?
Thanks,
---dens
SexyMF
09-22-2006, 01:55 PM
Just hold on to the capacitor. It will keep.
Running the compressor to air isn't good for the oil.
If the lines are open to air at the moment then the oil is turning to acid already.
Personally I have done it. I just put in a larger filter/dryer with acid scrub inside it. The are only around $15-20 dollars. Then you can rest easier that it is filtering out all the crap in the system.
Yeah I had a feeling I should probably replace the oil in it at some point anyway. I'll be using R290 in it, which leaves me open to most options. I can't see myself using a different refrigerant in the future anyway. Would just a can of POE oil do the trick? Then pouring out the old stuff, measuring then putting the same amount of POE back in.
This is actually the first time i've bothered to replace the oil. Both of my previous units were pretty experimental so I just want to do this one right.
However, what would I use the cap for in future anyway?
---dens
I just realised that when I disconnected it I crimped the ends and brazed them shut! :) I'll be using a brand new FD and i've always got a backup if I need to replace it down the track.
Might get started with brazing a few things up today. I can't do the condensor yet as I want to use compression fittings on it like this (http://www.xtremesystems.org/forums/showthread.php?t=92563). I'm using an identical condensor to that one (compare to the pic on first page) and i'd rather not cut off the threaded joints on the condensor just yet.
So yeah, guess i'll braze it up, cut off the lines to the condensor for now until I can manage to get some compression fittings for it.
---dens
wdrzal
09-22-2006, 06:59 PM
compression fittings (compression rings) are not used in refrigeration.
Flare fittings or Braze. you can argue that a flare fitting is technically a compression fitting because in engineering terms ,compression is what makes the seal. be sure if buying a flaring tool it is a 45degree one.
Well I'd always talked about them as compression fittings as that's what made the seal. The flared pipe connecting with the nut behind it pressing up against the join is what I was talking about, exactly what you can see in that thread I linked to (this one. (http://www.xtremesystems.org/forums/showthread.php?t=92563))
Anyway I just did a bit of brazing. As much as I could do but I don't have any couplings to join 1/4" pieces together so i've gotta wait til monday to get some more. I made my desuperheater as well using a fruit salad can.
The discharge line was originally made of aluminium, so I might have to cut it off completely somehow and take the line all the way back to the compressor. Not entirely sure how i'll do it but we'll see.
I decided to drain the oil anyway and get it replaced, and i'm quite glad I did. The best way to describe how it is right now is orange. I might take a pic later but It really doesn't look too healthy. So replacing it with the same amount of Polyol-Ester oil will do the trick?
---dens
SexyMF
09-23-2006, 01:25 PM
So replacing it with the same amount of Polyol-Ester oil will do the trick?
Sounds good.
Also, a desuperheater isn't something found in a single stage rig. A turn or 2 before the condensor is only used to dampen vibration.
Sounds good.
Also, a desuperheater isn't something found in a single stage rig. A turn or 2 before the condensor is only used to dampen vibration.
That's part of the reason why, but mainly people use it to remove excess heat before it enters the condensor, generally when trying to compensate for using a smaller condensor. The one i've got is pretty bloody small in comparison to what i've been using in the past, and it isn't that out of the ordinary to have one in there.
---dens