Discharging start capacitor before removal

Reply

  #1  
Old 06-22-09, 08:02 PM
B
Member
Thread Starter
Join Date: Dec 2008
Location: central california
Posts: 28
Received 0 Votes on 0 Posts
Discharging start capacitor before removal

I'm replacing the start capacitor on my RV air conditioner with a hard start capacitor (Supco SPP6E). What is the best way to discharge the capacitor that is on the unit now? I was told to use a screwdriver to arc between the two poles. Will this work without causing any harm to the rest of my unit? Suggestions???
 
Sponsored Links
  #2  
Old 06-22-09, 10:29 PM
A
Member
Join Date: Oct 2005
Location: Milwaukee WI
Posts: 1,339
Received 0 Votes on 0 Posts
Originally Posted by bob213 View Post
I'm replacing the start capacitor on my RV air conditioner with a hard start capacitor (Supco SPP6E). What is the best way to discharge the capacitor that is on the unit now? I was told to use a screwdriver to arc between the two poles. Will this work without causing any harm to the rest of my unit? Suggestions???
Not exactly the same but maybe you could do something like this.

Many years ago we used home-made probes with a resistor to discharge picture tubes. Pretty simple, just a larger gauge, sharpened probe wire soldered to one lead of the resistor, and a wire with an alligator clip soldered to the other lead. Disconnect power, connect alligator clip to ground, insert probe under anode cap, hear ZAP, remove probe, remove anode cap, probe hole again, all done. Seems to me we would leave the probe in place just to ensure there was no residual charge left.

This thread suggests using a 10K-ohm resistor, although I have used a screwdriver and an alligator clip jumper many times:
How to discharge high voltage in tv tube
 
  #3  
Old 06-23-09, 01:20 AM
F
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,807
Received 0 Votes on 0 Posts
I used the screwdriver to short out the capaitors { only at the capaitor termail point anywhere else forget it it will not work the reason why due the starting switch can isoliated it that why I mention that in first place }

That I been done doing that for long time.

Merci,Marc
 
  #4  
Old 06-23-09, 06:17 AM
R
Member
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,233
Received 1 Vote on 1 Post
The proper way to discharge a cap is to use a resistor as Arg suggested. It allows the cap to discharge slowly.

Wear safety glasses if you use a screwdriver. Capacitors can release all kinds of nasty chemicals when they explode. Remember, caps are just like batteries.
 
  #5  
Old 06-23-09, 09:35 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,943
Received 43 Votes on 41 Posts
Originally Posted by ArgMeMatey View Post
Many years ago we used home-made probes with a resistor to discharge picture tubes.
This is the safe, correct way.

I used the screwdriver to short out the capaitors
This is the way pretty much everybody does it.

Some caps have a bleed resistor built-in so it will automatically discharge itself after a few seconds of no power.
 
  #6  
Old 06-23-09, 10:48 AM
Z
Member
Join Date: Jun 2009
Posts: 7
Received 0 Votes on 0 Posts
For discharging an ac capacitor do you need the power to the unit on
 
  #7  
Old 06-23-09, 10:53 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,943
Received 43 Votes on 41 Posts
Originally Posted by zacktx View Post
For discharging an ac capacitor do you need the power to the unit on
Definitely not -- that could kill you.
 
  #8  
Old 06-23-09, 11:28 AM
B
Member
Thread Starter
Join Date: Dec 2008
Location: central california
Posts: 28
Received 0 Votes on 0 Posts
Thanks everyone. I picked up a resistor this morning. For less than $2, I'd rather be safe. Really appreciate all the help here!!!
Bob
 
  #9  
Old 06-24-09, 12:07 AM
F
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,807
Received 0 Votes on 0 Posts
Originally Posted by zacktx View Post
For discharging an ac capacitor do you need the power to the unit on

That is not a wise advise in here and it is too dangerous to do that.

Merci,Marc
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: