How can a Philips AC-DC transform make so much noise?
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From: Merciadri Luca on 17 May 2010 16:54 On May 17, 5:27 pm, ehsjr <eh...(a)nospamverizon.net> wrote: > Merciadri Luca wrote: > > On May 17, 12:05 am, John Fields <jfie...(a)austininstruments.com> > > wrote: > > >>If it's annoying to the point where it's depriving you of sleep, then > >>If it were me I'd let them know about it. > > > But you know, their servicing is always the same. That's the problem. > > >>It's your life though... do what you like. > > > I can deactivate it, but, clearly, it is annoying. > > Well, you've put in time and effort to post here. Why not > put in time and effort to contact Philips, as John mentioned? > Who knows - they might have a product recall on the thing, > or a simple fix. In any event, it couldn't hurt so you > might as well try it. Thanks. Done. I'll let you know. > For a possible "quick fix", try putting a piece of foam > rubber or a terry cloth towel under the thing to see if > that damps the sound. It is on an `electrical extension' (I don't know if this is how you call this) that I always disconnect, except when I want to charge the shaver. The problem is that if I need it tomorrow, I cannot charge it in my bedroom the night. Or, if I dare do this, I won't sleep(!), but will be shaved tomorrow. Funny.
From: Bob Masta on 18 May 2010 07:18 On Sun, 16 May 2010 02:50:39 -0700 (PDT), Merciadri Luca <merciadriluca(a)gmail.com> wrote: >Hi, > >I am using a Philips HQ 8000 100-240V /D 50-60 Hz, 9W, shaver charger >and transformer. I always let it plugged in, and then, to charge the >shaver, I plug the shaver in the charger, and everything's right. > >However, it makes a very irritating noise, some piercing one, even if >the shaver is not plugged. This sound is so much unbearable that I >have to disconnect it before going to bed. I know that, practically, >it is disadviced to let a transform connected to the network without >any output, but why is it making so much noise? I have dozens of other >transformers which never make such a noise. > >Thanks. Does the shaver actually plug into the charger via electrical contacts, or is it inductively coupled? If the latter, there are coils of wire in the charger and shaver that form the primary and secondary windings of a transformer. The alternating magnetic field in the charger primary induces a current in the shaver secondary, but unlike a conventional transformer where the windings are (hopefully) firmly attached to each other and an iron core, here the shaver is more-or-less free to move. Try pressing pressing and holding the shaver into the charger to see if that reduces the sound by restricting motion. If that quiets it down, you might rig up something like a heavy rubber band to hold them together. Another possibility is that the coils in the charger and/or shaver are not securely mounted. That would fit with the observation that you hear sound even when the shaver is not plugged in. If you can open the charger (disconnected from the mains!) and get to the coil, you may be able to anchor it with glue. Best regards, Bob Masta DAQARTA v5.10 Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, FREE Signal Generator Pitch Track, Pitch-to-MIDI DaqMusic - FREE MUSIC, Forever! (Some assembly required) Science (and fun!) with your sound card!
From: Merciadri Luca on 18 May 2010 08:51 On May 18, 1:18 pm, N0S...(a)daqarta.com (Bob Masta) wrote: > Does the shaver actually plug into the charger via > electrical contacts, or is it inductively coupled? > If the latter, there are coils of wire in the > charger and shaver that form the primary and > secondary windings of a transformer. The > alternating magnetic field in the charger primary > induces a current in the shaver secondary, but > unlike a conventional transformer where the > windings are (hopefully) firmly attached to each > other and an iron core, here the shaver is > more-or-less free to move. > > Try pressing pressing and holding the shaver into > the charger to see if that reduces the sound by > restricting motion. If that quiets it down, you > might rig up something like a heavy rubber band to > hold them together. > > Another possibility is that the coils in the > charger and/or shaver are not securely mounted. > That would fit with the observation that you hear > sound even when the shaver is not plugged in. If > you can open the charger (disconnected from the > mains!) and get to the coil, you may be able to > anchor it with glue. Thanks for this answer. Actually, it is not charged by inductive couple. There are simply two pieces of a conductive material at the bottom of the dock, and plugging the shaver into the dock results in a contact between the shaver and the charger, which therefore charges it. I contacted Philips, and this is definitely not normal, they said. I should get another one later. If I have some spare time, it is possible for me to open the transformer, and check if everything is right, this one being disconnected from the mains. Can I also open the transformer? Thanks.
From: Bob Masta on 19 May 2010 08:19 On Tue, 18 May 2010 05:51:55 -0700 (PDT), Merciadri Luca <merciadriluca(a)gmail.com> wrote: >On May 18, 1:18=A0pm, N0S...(a)daqarta.com (Bob Masta) wrote: >> Does the shaver actually plug into the charger via >> electrical contacts, or is it inductively coupled? >> If the latter, there are coils of wire in the >> charger and shaver that form the primary and >> secondary windings of a transformer. =A0The >> alternating magnetic field in the charger primary >> induces a current in the shaver secondary, but >> unlike a conventional transformer where the >> windings are (hopefully) firmly attached to each >> other and an iron core, here the shaver is >> more-or-less free to move. >> >> Try pressing pressing and holding the shaver into >> the charger to see if that reduces the sound by >> restricting motion. =A0If that quiets it down, you >> might rig up something like a heavy rubber band to >> hold them together. >> >> Another possibility is that the coils in the >> charger and/or shaver are not securely mounted. >> That would fit with the observation that you hear >> sound even when the shaver is not plugged in. =A0If >> you can open the charger (disconnected from the >> mains!) and get to the coil, you may be able to >> anchor it with glue. >Thanks for this answer. Actually, it is not charged by inductive >couple. There are simply two pieces of a conductive material at the >bottom of the dock, and plugging the shaver into the dock results in a >contact between the shaver and the charger, which therefore charges >it. I contacted Philips, and this is definitely not normal, they said. >I should get another one later. If I have some spare time, it is >possible for me to open the transformer, and check if everything is >right, this one being disconnected from the mains. Can I also open the >transformer? Thanks. Are you saying that the transformer is a separate unit from the charger? Whichever the situation, if the noise is coming from the unit with the transformer, it's possible that the windings are loose on the core, and might be fixed by a little glue. As far as opening the case goes, many of these are welded plastic with no convenient screws to remove. I have had luck in the past cutting open a wall-wart and re-glueing it later... worked fine, but it sure looked ugly! Best regards, Bob Masta DAQARTA v5.10 Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Sound Level Meter Frequency Counter, FREE Signal Generator Pitch Track, Pitch-to-MIDI DaqMusic - FREE MUSIC, Forever! (Some assembly required) Science (and fun!) with your sound card!
From: Merciadri Luca on 19 May 2010 11:59
On May 19, 2:19 pm, N0S...(a)daqarta.com (Bob Masta) wrote: > On Tue, 18 May 2010 05:51:55 -0700 (PDT), > > > > Merciadri Luca <merciadril...(a)gmail.com> wrote: > >On May 18, 1:18=A0pm, N0S...(a)daqarta.com (Bob Masta) wrote: > >> Does the shaver actually plug into the charger via > >> electrical contacts, or is it inductively coupled? > >> If the latter, there are coils of wire in the > >> charger and shaver that form the primary and > >> secondary windings of a transformer. =A0The > >> alternating magnetic field in the charger primary > >> induces a current in the shaver secondary, but > >> unlike a conventional transformer where the > >> windings are (hopefully) firmly attached to each > >> other and an iron core, here the shaver is > >> more-or-less free to move. > > >> Try pressing pressing and holding the shaver into > >> the charger to see if that reduces the sound by > >> restricting motion. =A0If that quiets it down, you > >> might rig up something like a heavy rubber band to > >> hold them together. > > >> Another possibility is that the coils in the > >> charger and/or shaver are not securely mounted. > >> That would fit with the observation that you hear > >> sound even when the shaver is not plugged in. =A0If > >> you can open the charger (disconnected from the > >> mains!) and get to the coil, you may be able to > >> anchor it with glue. > >Thanks for this answer. Actually, it is not charged by inductive > >couple. There are simply two pieces of a conductive material at the > >bottom of the dock, and plugging the shaver into the dock results in a > >contact between the shaver and the charger, which therefore charges > >it. I contacted Philips, and this is definitely not normal, they said. > >I should get another one later. If I have some spare time, it is > >possible for me to open the transformer, and check if everything is > >right, this one being disconnected from the mains. Can I also open the > >transformer? Thanks. > > Are you saying that the transformer is a separate > unit from the charger? The charger is connected to the transformer with a wire, simply. I plug the shaver in the charger. > Whichever the situation, > if the noise is coming from the unit with the > transformer, it's possible that the windings are > loose on the core, and might be fixed by a little > glue. As far as opening the case goes, many of > these are welded plastic with no convenient screws > to remove. I have had luck in the past cutting > open a wall-wart and re-glueing it later... worked > fine, but it sure looked ugly! I'll know the problem thanks to Philips. Thanks. :-) |