Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

12" Philco field coil speakers
#2

As a starting point we need to know what kind of radio those speakers came from. The designed voltage drop, current, and power dissipation could probably be calculated from data on the schematics.

I have worked on a Philco 41-280 with a 12 in, 1100 ohm field coil speaker and also some very similar other radios with 1100 ohm coils, but with smaller cones. If you are using a speaker from one of these or a similar radio, the following calculations should apply.

I calculate that these radios were designed to run around 66 milliamps through the field coil, which calculates to a voltage drop of about 72 VDC and power dissipation of about 4.8 watts. A year or so ago I measured the field coil current and voltage drops in a 40-150, which has a 1100 ohm field coil, and it matched the calculations pretty well.

Now, if you are dropping 95 VDC across two 1100 ohm coils in series, then you are running about 43 milliamps through them and dissipating about 2 watts each. On the other hand, if you are dropping 95 volts across each coil, then you are running them at about 86 milliamps and dissipating about 8 watts each.

Again, if your speakers are from a different radio, the calculations could be very different.

John Honeycutt


Messages In This Thread
12" Philco field coil speakers - by Guest - 07-24-2008, 09:08 AM
[No subject] - by Raleigh - 08-19-2008, 12:10 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 610B oscillator wiring
Some info from Beitmans says late production. David   David — 06:06 PM
Restoring Philco 96
Oh wow! Just found this thread.  Brings me back to early days on this phorum.  I did a 96 back in 2017.  Thread here: ...rfeenstra — 06:05 PM
Philco 610B oscillator wiring
Thanks for the replies. It's not the really the hum that I am after. Just trying to understand why only the shortwave ba...Tubester — 04:01 PM
Restoring Philco 96
70 and 90 are Superhets, but at least the 2x45 model of 90 uses the Plate detector (and so does 70). Also the Atwaters,...morzh — 03:28 PM
Restoring Philco 96
Morzh, Prayers for your mom. I am sure that there was enough pain living through the Holocaust as a child. I pray dail...MrFixr55 — 02:19 PM
Philco 610B oscillator wiring
Hi Dan, Divide and conquer. First off trry to differentiate between 60Hz and 120 Hz hum. 120 Hz hum has a higher pit...MrFixr55 — 01:49 PM
Restoring Philco 96
Yes, other than takin a toll on your back, they are undeed way more repair friendly than many other Philcos. To me, som...morzh — 01:04 PM
Philco 610B oscillator wiring
If the wires look like they were this way from the factory (very neat and very dull soldering joints), I'd leave them be...morzh — 12:58 PM
My Philco 37-116 Restore
I managed to open up the Expander Unit and replace the grid cap wires. Tested the connections found they looked good and...dconant — 12:19 PM
610B Oscillator Questions
I've included a picture of the 'actual' schematic I created. I double checked several times and it appears to be accur...Tubester — 09:26 AM

[-]
Who's Online
There are currently 2445 online users. [Complete List]
» 2 Member(s) | 2443 Guest(s)
AvatarAvatar

>