Discharging Run Capacitors - Or NOT to discharge? :)

[2Bibleppl]

Okay, I have one of those piece of junk Goodman heat pumps. We purchased it new and it was installed in 08' Every year we have a capacitor to go bad. The tech put a "hard start' in and it has just happened again. Last night when the unit tried to come on the lights dimmed severly several times in a row to the point that it really concerned me. Tomorrow the tech comes back to try to figure out what the problem is. Any advice would be greatly appreciated. Thank you for your time and trouble.

[hackfreehvac]

@2Bibleppl

Lights dimming for more than a split second definitely would indicate that the compressor is not starting right away or at all.

Make sure all the high voltage wires are tight at the disconnect and at your main breaker panel.

A voltage drop may add to the problem. But it probably would have smoked the breaker/disconnect terminals by now if it ran like that for more than a year or so.

[2Bibleppl]

@hackfreehvac

Thank you so much, the two tech guys are here now and have found exactly what you just mentioned. Last night we turned the system off and used an infared suntech space heater in one room, we didn't want to take the chance of a fire because the first time it happened we woke to a fire, bad news there [ but no injuries] Thank you so very much for sharing your knowledge with us. Take care.

[als3lo]

it is trane ac

مكيف ترين 20 طن

[findvoltage]

hi again, i ment run-start capacitor, as a single unit. if it does exist can you give me an example how it works, i know that two metal foil sheets hold a charge and relese that charge, but a normal start cap would malfunction if i used it for a run CAP. so what is the difference between the two, thanks

[hackfreehvac]

@findvoltage

Start capacitors are quite higher in capacitance, which applied to the same motor winding as the run cap allows much more current flow than the lower microfarad run cap.

The start cap is also in a plastic enclosure which is not going to reject the heat well either.

However, they are only used MOMENTARY via a potential relay for extra starting torque of a motor.

The run caps are designed to be in the the entire time the motor is running.

[findvoltage]

@hackfreehvac thank you for your time it is very much appreciated.

[ToledoApplianceGuys]

thats so true

[catdaddy750]

ok sr. i have a question my home air conditioning burn a wire twice on two different weeks. do you know whats wrong with it ? 

[piper4seeformerly]

I noticed this too. I bought an old air conditioner motor and dual run capacitor at a yard sale and everytime I turn it off after running it i get no spark at the capacitor terminals. I even check the capacitor terminals with a multimeter set to DC voltage after I unplug the power cord and zip zero zilch.

[cheerdiver]

Kudos, I like the EMP effect on the microphone w/ direct exposure.

Hunans can't hear underground nuke detonations, <10Hz

[hungarylnnjsd]

Free energy has been here for a while ,But the Establishment doesn't want ppl to know this,Find this technology at LT-MAGNET-MOTORdotCOM ,Be the revolution!

[ArtistBlade1972]

Excellent video. Good to see people with a good understanding of how things work making videos unlike some people on here. This is the very reason you never see a bleeder resistor on a run cap. If I may add something- If there is any charge remaining on the cap (as in the demo) it will be read as a dc voltage across the cap. I'm sure you know this, but other people may not. If it is charged and you check it with your meter on ac you will read 0 with the power removed...

[newstart49]

As one who has been there and done that, it takes less than a second to discharge a cap- do it anyway. Caps for compressors (single phase) should always be discharged if the contactor is open. You can short at the cap or push the contactor closed to do so. The first thing is to be safe.

[hackfreehvac]

@newstart49

You should have read my info first. I do not recommend people taking chances. But I was explaining WHY a capacitor wont be charged unless the motor winding attached to it opened while energized.

On single phase equipment, the run cap is wired directly between the RUN and START winding, thereby discharging itself.

The ONLY way to get a charged run cap is to pull the wire when it is running as I did.

Start caps are the exception because wired different.

[captain150]

Why do the fan motors turn slowly like that?

[hackfreehvac]

@captain150

When it's cold out, only one fan runs. The other was just "wicking" (turning form the air of the other fan).

[2003SCT]

Do you have to charge these capacitors or just install them. The reason I ask is because the large car audio capacitors need to be charged prior to installing them and I figured these would work the same way conceptually. Or is it more of a plug and play? Thanks in advance!

[hackfreehvac]

@2003SCT

Well the "filter" caps used for DC stuff in cars are for a different purpose.

I don't know why they would need to be charged first. Maybe to keep them from blowing the fuse, as connecting a large drained cap to a battery would draw a quick spike of current at first.

[Marzec309]

@hackfreehvac Agreed, connecting a large dc cap as in car audio when its drained can easily blow 200amp fuses. Not to mention weld the wires to the terminal of the cap. Car audio caps are in the range of 0.5 farad to 20 farad and even larger. Starter and run caps used on motors are in the range of 0.000005 farad(5uF) to 0.000040 farad(40uF). They are significantly larger.

[hackfreehvac]

@Marzec309

I figured as much. :-)

[bigbobgotu]

@2003SCT the only reason a car capacitor need to be charged is so i dont blow your fuse

[trttawnwmm]

thanks for the help

[kolocho7777]

where did u learn to work on this big systems?

[lightman47]

Ok, this is true, UNLESS the motor has a bad winding or is wired wrong, then the cap WILL have high voltage on it. Always be safe and discharge

[deyenak1]

What about the older units? Will they discharge themselves?

[Sharkie626]

Hey! this is a very good video! :D

So when you disconnect that wire when the unit is on you said that the motor keeps running but it is using higher amps? Also what happens when the brown wire or the (purple?) wire is disconnected before you turn it on, would the fan motor not run at all?

[lightman47]

If you diconect the purpple wire, it will not run at all. The purple is the common wire

[OddlyIncredible]

Many motor caps also include integrated snubber resistors that will drain off the charge in a few minutes. However, never assume a cap is discharged - always, ALWAYS run a voltage check before reaching into anything sporting caps charged to over about 50WVDC.

[Alxscode]

Would a rubber or latex glove prevent an electrical bite? Is this a good or bad idea?

[simsrunit]

when replacing the condensor fan motor do i need to dischare the capacitor

[umajunkcollector]

TV picture tubes, and microwave oven caps, DO hold a nasty charge. And it is NOT a good idea to short them out with a screw driver either. And they can hold a charge for a long time too! bEWARE when poking around inside a TV or radar range.

[Driv3th3hiv3]

Microwave capacitors arnt dangerous

Most dont go past 5 Joules (16 being the threshhold for letahlity)

But it will give you one hell of a jolt

[buckners1]

I got bit by a compressor with a burned terminal on the start winding. I pulled the disco, checked voltage, the back of my hand hit the cap when I was checking something else. It was an 80Mf @440V, a 67K scroll compressor on a pool heater.

I realized (a little too late) because the start winding wire burned off the cap could not discharge...........until I touched it.

[hackfreehvac]

Yup, that will be one of those times when it holds a charge! I bet that stung a little bit!

Of course as I mentioned in my video, I am referring to units that are operating fine that shouldn't need the cap discharged. I've been bit by a few run/start caps. Always from a burnt wire that left it charged. :-o

[MauField]

you might be able to answer this, I am wanting to know if I can take my 220 and find away to up the voltage to 460? my welder does not run well at 220 at all. so maybe a step up of some kind?? or should I just call local and see if they can run me a new lead?

[hackfreehvac]

Does your welder support 460V? I have a wire feed and it only runs on 115 yet does pretty good. You would need a MASSIVE step up transformer to get the 460 from an existing 230 running that kind of current. Unless you were at a commercial area where they had their line voltage stepped DOWN to 460 for a feed to your business.

[KROUTCHY]

u may try to reduce the number of windings...but only if u know what are u doing

[aircooledtx]

Hey, don't tell anybody , but when I was young and stupid I heard a compressor running through a wire and into my head. Customer said unit power was off, so dumb me did not check for voltage and grab a hold of start wire and had my hand on unit so I was ground made the circuit for start and compressor fired right up with me in the middle..

[hackfreehvac]

I'm sure that tickled a little bit!

[mazzmari]

Excellent video.

[hackfreehvac]

Thanks. Thought you'd like. :-)

[hemiownzu]

I always take my nut driver and run it across a cap. Every now and then I'll see and older unit like a late 80's ge/trane with the bleed resistor on the cap.

[hackfreehvac]

Yup. I think those had the bleed resistor because they had TWO run caps. One was in the circuit at all times to allow some current to flow through the start winding to act as a crank case heater. The second run cap paralleled into the circut (to give the correct microfarads when rinning) when the contactor closed. I think when the contactor opened it left the one run cap isolated from the circuit, therefore it could hold a charge. The bleed resistor discharged it so you wouldn't get shocked. :p

[Straycurrent]

A shocking demonstration. Ha, ha. Why do I feel an actual jolt just on seeing the spark in the video? I think I've felt it more often than I wish to admit.

[hackfreehvac]

The spark was so loud that it would cause the camera's mic gain to go to zero for a few seconds. It really didn't capture how loud the spark really is when you short a cap like that. :-)

[PutSome5tankOnIt]

The Doc is NOT a wuss. I've been bitten by a circuit that was NOT properly labeled, or connected by 'Sparky' (aka, 'the electrician').

Never trust panel markings. I've seen air conditioners receiving voltage from two different two-pole breakers. It DOES hurt.

Take a few seconds to test it. Non-contact voltage. Voltage to ground. Better to be safe than sorry.

Good video, hackfreek.

[hackfreehvac]

That's why I mentioned "on a properly running unit" it would be discharged. I do get shocked every once in a while. But it just keeps you on your toes.

[mechanicwarrior20]

Good video I would like to mention too that a motor is an inductive load and thus would discharge the run cap.

Also if you put your volt meter across the terminals on a capacitor you would discharge the run cap because a volt meter is considered to be a load.

[hackfreehvac]

Yup. The meter discharges it more slowly than the motor winding. The motor I tested in a video was like 140 ohms. The multi-meter would be very high resistance, but I do notice it slowly discharges as I hold the leads to the cap when reading volts.

[277Ballast]

Good vid I asked Zarloff to make one and he must be too scared to do it so he pushed it off on somebody else and he just said use a screwdriver. thanks for actually doing it.

[hackfreehvac]

I can't say I haven't put a screwdriver across some run caps. If it's not a cut and dry circuit, or if the motor was bad, it's a good idea to short them. But on normal PM calls when I saw the motors were working, I don't bother to short them.

[towbinJosh]

Wow I can't Thank you enough!!!!!! Love the video!!! btw would this also be true for caps in hid lighting fixtures?

[hackfreehvac]

I have no idea about the lighting fixture. If it has a load across the terminals it would discharge. If it's isolated when the power is off, then it could hold the charge for days.

[DrZarkloff]

You can call me a wuss. I discharge the run caps as a safety habit.

[hackfreehvac]

LOL! I've been bit once by a run cap. I wondered why and then found that the fan blade tangled up a wire and broke it free from a motor while it was turning. Got the call as a no cool and found the ODM not operating. When I reached in to pull wires from the run cap to check it, I got zapped! It feels real good too! But not nearly as bad as a capacitor in a microwave oven or the flyback of a TV set. Yeeowch! :-o

You sure found the video fast. :-) I am home because we are slow. :-(

[hackfreehvac]

Anyway. Like the video says, I was doing this as a demonstration. I had a few messages sent to me asking HOW to discharge run caps and if it was needed. Hopefully it shows why they typically can't hold a charge, and what power they do have when they do! :-] I probably wasn't leading a good example when I was working in this unit with no gloves on. Forgetting to turn of the supply power would be bad news when you reach into one of these without gloves!

[jimmymoss7644]

i was zapped the same way but by a burnt wire on a comp! i was lit up!

[mikie2501]

Very nicely done! Got bit by an old PCB cap the other day myself. Oh, btw, you bastard! I want to be home laying around!! it's saturday and I had to run 6 stinking heat calls! ..did I mention I hate heat pumps? heh. :>

[hackfreehvac]

Is it cold in your climate?

It was in the 90's again today. Had to run some no cool calls out here!