i'm trying to understand power transformers. this is from the hammond 270bx.
"The 270 Series power transformers use the convenient 4 hole above chassis "X" type bell end mounts. Each unit features a 115 VAC, 60 Hz primary and two secondary filament windings, one 5.0V for tube rectifiers, plus a 6.3V for heater filaments. Leads are a minimum of 6" in length. Class A insulation (105ÂșC). These transformers are conservatively rated and CSA certified. VA: 95, Secondary RMS: 300-0-300, DC mA: 100, Fil. #1 Rectifier: 5.0V/2A, Fil. #2 Heater: 6.3V/3.0A."
115VAC, 60Hz primary = what it needs from the wall (mains) to go.
300-0-300 secondary = one tap will be +300VDC, another -300VDC, and the center is neutral. 600VDC across the entire secondary.
100mADC is secondary current flow = 30W of power to the speaker?
[300VDC*.1ADC=30W]
95VA = apparent power the amp is making?
am i understanding that right? CT is center-tapped meaning the leads come off the secondary winding wire in the middle of the wire? like if you straightened it out. so this transformer is a 3 phased, CT power transformer?
it has taken me 3 days to pull all of these "ideas" together b/c i can't find anywhere that explains this all in layman's terms (ie. the 270bx needs input of 115V @60Hz to make 300V out which will be a replacement for a 30W amp). or maybe: X model transformer goes into Zwatt amp, and here is why.
however, i have learned a lot of other things: did you know that money does not grow on trees? i never knew that.
pj
Quote115VAC, 60Hz primary = what it needs from the wall (mains) to go.
correct
Quote300-0-300 secondary = one tap will be +300VDC, another -300VDC, and the center is neutral. 600VDC across the entire secondary.
The voltage is still AC at this point. If you measure across the 2 legs with a meter set to AC you'll measure 300V.
I used a 270 in a tube amp that I built. Most SS amps use transformers with lower voltage and higher amperage.
Do you need to replace a transformer or are you just curious about the ratings?
thanks allgood. the rectifier turns it into dc. and, not sure if i lost pt or not. no pwr when i used the bulb limiter. i'd previously posted that i'd checked everything but the caps. but, now i'm in doubt as to my checking proceedures (read: sequence). so, i'm back to square one. but, won't make that mistake again. also getting a lot of practice w/the iron.
so, a 48v ct, 3A pt would work, wouldn't it? that would be 144VA (RMS). wouldn't that come out to @ 50-60W to the speaker? would that do it? or too low? why?
pj
It all depends on the circuits' requirements. You'll need a schematic or a Crate part number to find the right transformer. You might be able to see if there is a number on the transformer and find out it's ratings.
yeah, i'm waiting to hear back from crate w/part# and schematic. the ONLY markings on the transformer are two stickers. one has an SLME #, the other says, "High Pot Tested". i can't find any references to any crate part#'s.
Check your email papajeaux... ;)