


Magnetos, Ignition Coils and Spark Plugs Discussion about magnetos, buzz coils, spark plugs, ignitors and low tension coils. 
Magneto charger magnetizerthis thread has 16 replies and has been viewed 1191 times


Thread Tools  Display Modes 
#1




Magneto charger magnetizer
Hi there from the uk
I have been building a magnetizer i plan to use on mains voltage , When carrying out tests i have found when my coils are connected in series the ohms reading is 35ohms, i have connected them in parallel and i get a 9ohms reading. Would it be better to have them connected in parallel as the amp draw would be higher? Hope someone can help. Andrew 
Sponsored Links 
#2




Re: Magneto charger magnetizer
It would all depend on how you wound the coils.
Do yourself a favour and get a book call by David Gingery entitled "How to build a Magneto Magentizer" Well worth the read. Cheers Scott 
The Following User Says Thank You to Scotty 2 For This Post:


#3




Re: Magneto charger magnetizer
Not sure how many turns your coils have. Assuming rectified mains voltage of 240V, current through the coils in series is about 6.8A. In parallel, the total current would be 26.7A, or 13.35A per coil. So if we assume you have 1000 turns in each coil, you'd have 2000 times 6.8, or 13600 ampereturns in series. In parallel, each coil would have 13.35 times 1000 or 13350 ampereturns, or 26700 ampereturns total.
Connecting them in parallel would definitely provide more ampereturns, but the current is significantly higher. Also the heat generated would be significantly higher. Since power is current times voltage, each coil in parallel would need to handle 13.35 * 240 = 3204 watts. Not unreasonable for short duty factor. Given the higher ampereturns generated in parallel, I'd do that if you can safely supply the current. 
#4




Re: Magneto charger magnetizer
The other thing to consider is the saturation magnetization of the pole pieces. This is how efficiently the pole pieces on your charger converts amp turns to magnetism to deliver to the magnet to be charged. https://en.m.wikipedia.org/wiki/Satu...ion_curves.svg
Certain iron alloys support a much higher field strength; cast steel and silicon steel allowing about twice the field for far less amp turns than other ferrous alloys. If your coil saturates the pole pieces, then no additional amp turns will get you more field and higher charge. So bigger is not necessarily better. I made my charger from two truck starter solenoids (several thousand turns) and at 12 volts, both coils wired in parallel and probably drawing like 1520 amps, I’d put it up against most other home brew units. Also make sure the bottoms of your poles are connected and fit tightly against the base plate to not have any air gaps which can diminish the total field strength. I haven’t read Ron Gs book but I have working schmartz since I’m a materials guy by trade.... still, since the coils are only used momentarily, give them what the mains will handle and what the wire will take without frying the windings... 
The Following User Says Thank You to PaulGray For This Post:


#5




Re: Magneto charger magnetizer
Called the Q of coil or efficiency. Basic electronics formulas. Have most memorized after 43 years.

#6




Re: Magneto charger magnetizer
I would have thought if both coils had the same resistance that in parallel the resistance would be 17.5 Ohms instead of 9 Ohms.

#7




Re: Magneto charger magnetizer
The formula for calculating resistance of parallel resistors is
1/Rt = 1/R1 + 1/R2 Going through some basic algebraic multiplication and division, you can end up with Rt = (R1 * R2) / (R1 + R2) So if the coils total 35 ohms in series and otherwise close to the same resistance of 17.5 ohms each, you end up with Rt = (17.5 * 17.5) / (17.5 + 17.5) which is 8.75, close to the measured 9 ohms. Saturation of the core material is something I didn't consider, and would certainly factor into the decision to go in series or parallel. 
The Following User Says Thank You to neonman For This Post:


#8




Re: Magneto charger magnetizer
Regarding the coils they was not wound by me i acquired the coils from someone else who had started the project.
The cores measures 2 3/4 " diameter and length 10" The wire used is 18 gauge enameled wire. I have run some test on low volts 12v dc battery and there feels a little more magnetic pull/ flux on parallel, the amps drawn on parallel at 12v is 1.3amp and 0.3 amp when wired in series ... 
#9




Re: Magneto charger magnetizer
look to me as if you have approx 830m of wire per coil this gives approx 3175 turns per coil
therefore in series 6350 turns at 6.8A = 43,000A/T very good for steel based magnets (horse shoe) but not enough for alnico types or in parallel 3175 x 13.5 x 2 =85,700AT exactly what lucas recommend for charging there magneto,s unfortunatley lucas also recommend a core area of 9sq inches but that must depend on the material the cores are made from hope this helps barry. 
The Following User Says Thank You to barry ayres For This Post:


#10




Re: Magneto charger magnetizer
I have now run the magnetizer on mains 240v in both series and parallel and there is a very strong pull in parallel (even the spanners on the wall move!)
One confusing thing when i initially tested it on 12v you could change the polarity of the battery and the north and south poles would switch round , but on the 240v when i switch the +  terminals on the rectifier the poles do not change, I was just wondering why this was?? 
Bookmarks 
Thread Tools  
Display Modes  


Similar Threads Chosen at Random  
Thread  Thread Starter  F o r u m  Replies  Last Post 
Magneto Charger  Geist  Magnetos, Ignition Coils and Spark Plugs  2  06222016 01:49:32 PM 
Magneto magnetizer  Neil Mactavish  Smokstak Down Under  15  04012014 09:59:45 PM 
Magneto Charger  GregNCA  Antique Gas Engine Discussion  2  11052010 10:48:06 PM 
Magneto Charger  mccormick98  Magnetos, Ignition Coils and Spark Plugs  5  02142010 11:10:14 PM 
Rex's Magneto Charger  Walt Beeman  Antique Gas Engine Discussion  5  05182009 09:59:59 AM 