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Title: The basement can be Cold and Lonely for transformers Post by: KB2WIG on January 08, 2015, 01:37:21 PM Its cold down here. So assembling the 813 rig will keep me warm. I've got the 810 modulator ready to marry the beastly 610 Mod Transformer. But are they both ready to accept each other? Hiding transformers from the wife while they in the oven to boil out moisture is a time honored tradition. (Maybe some YLs hide transformers from the OM.) I liked to put 'em in the car trunk in the summer. (The transformer.) Or variacing the primary with a small load on the 2nd. But watt to do with mod transformers?? They get thirsty too? I'd venture a guess that placing a small load to warm them up is OK. Any comments? klc Title: Re: The basement can be Cold and Lonely for transformers Post by: KL7OF on January 08, 2015, 02:57:51 PM put them behind the wood stove
Title: Re: The basement can be Cold and Lonely for transformers Post by: WD5JKO on January 08, 2015, 04:04:11 PM Here is a possibility.....for some large iron Configure the tranny as step down, then short out the secondary with a wire. Next hook up 120V from a wall outlet, and go through a incandescent lamp to the primary. Since the secondary is shorted, the primary will also be low impedance, depending on the degree of coupling primary to secondary. So start with a 50 watt lamp, and work up to 100 watts for a larger transformer. Both primary and secondary windings will be passing current (based upon turns ratio), and the current will vary with the wattage of the lamp. Since the wire will dissipate heat from current flowing through it, the tranny will heat from within. The trick is to not overdue it. Other options apply, like a getting a tan in the July Texas sun.. Jim Wd5JKO Title: Re: The basement can be Cold and Lonely for transformers Post by: flintstone mop on January 08, 2015, 04:52:04 PM Watt!!
The mod iron will not fit in the oven? F Title: Re: The basement can be Cold and Lonely for transformers Post by: W1ITT on January 08, 2015, 05:02:58 PM Collapse the cake rack in the oven with a transformer and there's going to be some 'splaining to do.
Title: Re: The basement can be Cold and Lonely for transformers Post by: Steve - K4HX on January 08, 2015, 07:21:42 PM Plywood, aluminum flashing and heating lamps. Build a box and bake away.
Title: Re: The basement can be Cold and Lonely for transformers Post by: N2DTS on January 08, 2015, 07:44:12 PM Put the mod iron IN the wood stove and go screen modulation!
Title: Re: The basement can be Cold and Lonely for transformers Post by: Opcom on January 08, 2015, 08:33:40 PM Here is a possibility.....for some large iron Configure the tranny as step down, then short out the secondary with a wire. Next hook up 120V from a wall outlet, and go through a incandescent lamp to the primary. Since the secondary is shorted, the primary will also be low impedance, depending on the degree of coupling primary to secondary. So start with a 50 watt lamp, and work up to 100 watts for a larger transformer. Both primary and secondary windings will be passing current (based upon turns ratio), and the current will vary with the wattage of the lamp. Since the wire will dissipate heat from current flowing through it, the tranny will heat from within. The trick is to not overdue it. Other options apply, like a getting a tan in the July Texas sun.. Jim Wd5JKO If you know the wattage and the secondary impedance, you can figure from that the current and avoid overdoing it. P = I^2 * R P / R = I^2 For example 500W and a 5000 Ohm secondary 500 / 5000 = 0.1 sqrt 0.1 = 0.316 amp There is a collection of old wives tales on this: 1.) The current can be checked with a resistor like 1 Ohm placed across the secondary. 2.) It should not be necessary to rush it or go overboard. Less is good as long as it warms it up. 3.) You can add a variac in case you don't have a lamp that give a close enough reading without being too much. 4.) If it ends up taking more than a 120V across the primary or any high power winding to make enough current flow. In that case step it up with a power transformer. 5.) Never use a low power feedback, monitor, or screen winding for this. 6.) Try to use the entire primary and entire secondary. I don't know how fast it works by the electric method but I heated a 960W Collins one for a week just to make sure, and same with the matching modulation choke using a DC supply. I prefer the oven for a day at 150 degrees but if I damage the baking rack or any tar runs out and stinks it up there will be no pie for me. ever again. 8-) Title: Re: The basement can be Cold and Lonely for transformers Post by: KB2WIG on January 09, 2015, 01:24:02 AM F, Yes, the mod iron will fit in the oven. But I have to sleep, and that's when the oven method will have its tragic end. S, S, B, P, D, J, Thanks fer the input. I'll bring it upstairs, and put it in the mud room for 3 or 4 days. Maybe I can find a cooler, and place the iron and a 'lectric lamp inside. It actually is behind the cellar wood/coal stove. klc |