Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Blowdryer issues

  1. Jan 11, 2005 #1
    My blowdryer just died a couple of days ago. I was going to repair it myself but I was afraid of being shocked. Now I have a new one, but I hate to see the old one go to waste. Truth is, I really*emphasis* want to take it apart and see how it works. However, my new dryer's manual states "DO NOT ATTEMPT TO REPAIR IT YOURSELF......electrical parts are electrically live even when the switch is off."

    I assume this is because it has a capacitor.

    I wanted to know if there is any safe way of taking it apart and examining it. If not...oh well :frown:
     
  2. jcsd
  3. Jan 12, 2005 #2
    They are covering their azzes with that warning.
     
  4. Jan 12, 2005 #3

    Cliff_J

    User Avatar
    Science Advisor

    Couple things:

    It should be safe if it is completely unplugged from the power outlet. Capacitors only store DC energy, the outlets are all AC and unless it was some super fancy variable speed unit (not two speed, but continously variable) it would stay AC throughout. If plugged in it should be considered dangerous and treated with respect.

    If it died, it has likely burned up a part that would cost nearly as much or cost more to replace than to purchase a whole new unit. Its not like the parts are that expensive but in a quantity of one it would be rare to find and shipping and distributor markups et cetera would make it expensive. A whole new hair dryer costs what, $15-20? So it should be no problem to trash the old one after you've taken it apart.

    Cliff
     
  5. Jan 12, 2005 #4

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    1) Make sure it is unplugged!
    2) Make sure it is unplugged!
    3) Make sure it is unplugged!

    A bigger problem is if you fix it wrong.
    Or put it back together wrong.
    It could start a fire or electrocute you.

    There won't be any residual charge in a blowdryer, unlike some electronic equipment.
     
  6. Jan 13, 2005 #5

    enigma

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    If there are any capacitors, you can carefully discharge them with a voltmeter. Just be sure you don't touch the leads with your fingers.
     
  7. Jan 15, 2005 #6
    I don't have a voltmeter; if I see a capacitor is there any other way to discharge it? Maybe I'll just work around the cap. And no, I wasn't planning on putting it back together and using it again. That is way too risky and I am not an electrician. I'm just going to take it apart and analyze it.

    It's going to be fun!!! I have to deform (smash) it to get it open because there are no screws holding it together. :(

    But thanks for your input..

    -Karen
     
  8. Jan 15, 2005 #7

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    Absolutely. Just cross the terminals with something which isn't your finger. (Something metal would help here.)
     
  9. May 12, 2005 #8
    Today I officially diassembled my dryer. Vidal Sassoon makes a tough product. But to my dismay, there were only resistors and a small metal piece (unknown). No capacitors. Wish I had a camera to show those who are interested. Next, I am going to dissect my old cell phone....
     
  10. May 12, 2005 #9

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    Good for you! I think most of the people in the Engineering forum here have spent many happy hours taking things to bits (and sometimes even putting them back together again!).

    Have fun with your dissecting. Just be careful with things like cameras (which can have some VERY big capacitors in them for the flash).
     
  11. May 12, 2005 #10

    russ_watters

    User Avatar

    Staff: Mentor

    Bah - as long as you de-energize it by laying a nail across the terminals of the capacitor...
     
  12. May 12, 2005 #11

    DaveC426913

    User Avatar
    Gold Member

    Holy Jeez - next you'll be telling him his microwave oven should be good for drying his hair...


    It is trivial to turn AC into DC. You need two components - one is a diode and the other is a capacitor!
     
  13. May 12, 2005 #12

    Cliff_J

    User Avatar
    Science Advisor

    Are you suggesting that telling someone new to experimenting with electrical items to unplug the device for their own safety is akin to doing something that would be harmful?
     
  14. May 12, 2005 #13

    Math Is Hard

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I was just reading this thread and thinking I would really like to see the inside of that blowdryer - I wonder if karen will post pictures? That might actually make a neat web project- you could put up pictures of things you've taken apart like blowdryers and cell phones.
     
  15. May 12, 2005 #14
    Well, I've got a picture of a disected super soaker gun if anyones intereseted :smile:

    On the topic of taking things apart safely it should be noted that there are indeed dangers lurking inside, EVEN IF they are disconnected from supply

    Obviously equipment that's just been used may get very hot, so let them cool for some time before going to work.

    As above capacitors have been mentioned. As you know capacitors store charge therefore are capable of electric shock, especially when you reach towards CRT circuitry which have thousands of stored volts in them. Hence why you should be VERY CAREFUL with the insides of a TV.

    Also merely putting a piece of metal across the terminal not only allows you to be shocked if your not protected, but a violent discharge to occur. Resistive loading would be much better, e.g. a voltmeter or a resistor.

    Also be aware of chemicals sometimes used in products too.

    If you're working with microcircuits (e.g. inside your computer) and intend to put it back together working again, be aware of ESD. A quick finger on a component can actually completely destroy the chips on the boards.
     
  16. May 12, 2005 #15

    DaveC426913

    User Avatar
    Gold Member

    No, I'm suggesting that merely unplugging a device from an outlet does not ensure it is safe.

    Especially when you go on to prematurely suggest that it won't contain any DC current (apparently, the reason being that it was AC at the outlet). Making DC current out of AC current is as simple as a diode and a capacitor. And a capacitor is the very thing that stores electricity when the device is unplugged.

    Try fooling with an unplugged TV and you will blow your brains out with 30,000 volts. Try a disposable camera (that's powered by itty bitty penlight batteries) and you will give yourself burns.
     
  17. May 12, 2005 #16

    DaveC426913

    User Avatar
    Gold Member

    I imagine those who need to be advised to avoid it probably don't know what 'ESD' is.

    (That'd be electro-static discharge.)
     
  18. May 12, 2005 #17

    Apologies, its just that its so common place at work everyone knows about it.

    For those who didn't know, ESD does indeed stand for electro-static discharge. It's the same as the electric shock you can sometimes get off a trolley when you walk around the supermarket. Although for us its a bit of a shock, for ESD sensitive devices (such as microchips) its a killer, and only needs to be much much less.

    Just by sitting down and moving around we can create 100's of volts, and when the humidity goes down below 25% (which is why ESD environments need humidity and temperature controls) this can reached thousands, again sitting down. We won't feel it, but it will destroy the device.

    That's why its important to keep fingers away from Printed Circuit Boards like in your PC. It's aways best practice to plug the computer in, BUT UNPOWERED, so that it's earthed and keep a hand on the chassis.
     
  19. May 12, 2005 #18

    The most dangerous voltage in a TV set is the 120 volt line. The second anode is 30,000 volts with very little current capability. The second anode voltage is certainly not as uncomfortable as an electic fence or voltage on a spark plug. The biggest danger when working in TV sets is ripping your arm up on the chassis when your reflexes cause you to quickly pull your arm out of the set. I've been shocked by the second anonde and collector on the horizontal output transistor and all that happened was I taught a few people around me some new words. :smile: Well, knowing those people, probably not.
     
  20. May 12, 2005 #19

    DaveC426913

    User Avatar
    Gold Member

    (That'd be "shopping cart".)

    Trolleys are indigenous to San Francisco.

    :)
     
  21. May 12, 2005 #20

    Cliff_J

    User Avatar
    Science Advisor

    Dave your comments seem quite out of place when there are other posts that warn of the hazards in a charged capacitor.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Blowdryer issues
  1. Transformer Issue (Replies: 1)

  2. Noise issues (Replies: 13)

  3. Switch issue (Replies: 4)

  4. Grounding issue (Replies: 7)

  5. Photosensor Issue (Replies: 0)

Loading...