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Identify giant transformer from 1978 tape reel

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bjbb:
"Ah wheres your sense of adventure.Anyone of us can walk you through identifying the winding s . 24VAC isn't  that dangerous."

More than hazardous voltage levels, there are also hazardous current, power, and energy levels that are defined in numerous standards. For yourself, Canada has CSA No. 223, and for the U.S. there is ANSI/UL1310. And I forget what is the NOM equivalent for Mexico. Everyone else has to use the standards scoped for the particular type of component or equipment.

Note that the the concept of a Class 2 power source is particular to North America, as no one else has fine taste in well-behaved electrons that are found in North America.

MarkF:

--- Quote from: bjbb on May 03, 2019, 12:35:00 am ---"Ah wheres your sense of adventure.Anyone of us can walk you through identifying the winding s . 24VAC isn't  that dangerous."

More than hazardous voltage levels, there are also hazardous current, power, and energy levels that are defined in numerous standards. For yourself, Canada has CSA No. 223, and for the U.S. there is ANSI/UL1310. And I forget what is the NOM equivalent for Mexico. Everyone else has to use the standards scoped for the particular type of component or equipment.

Note that the the concept of a Class 2 power source is particular to North America, as no one else has fine taste in well-behaved electrons that are found in North America.

--- End quote ---

I myself tend to plug the device into a long extension cord, stand far back, flip the switch and watch for the magic smoke from the "well-behaved" electrons.   :popcorn:  :-DD

mikerj:

--- Quote from: Jwillis on May 02, 2019, 08:12:51 pm ---The biggest problem with using a lamp to find how a transformer is configured is that the light draws current and some winding s on the transformer may not handle that current and could potentially burn up the winding s . The safest way is to use low voltage AC instead and measure with a multimeter .

--- End quote ---

The point of using a lamp is to wire it in series to limit the current, not to draw current.

Brumby:

--- Quote from: queennikki1972 on May 02, 2019, 09:34:39 pm ---I will use as a door stop, its safer!!  :-DD

--- End quote ---

Watch out.  It might be a toe-eater.

macboy:

--- Quote from: Jwillis on May 02, 2019, 08:12:51 pm ---The biggest problem with using a lamp to find how a transformer is configured is that the light draws current and some winding s on the transformer may not handle that current and could potentially burn up the winding s . The safest way is to use low voltage AC instead and measure with a multimeter .

--- End quote ---
The lamp is placed in series with the primary and the line voltage, not used to load the secondary.

A 60 Watt incandescent lamp will draw only 60 W when plugged directly across mains of rated voltage. Therefore the series combination of the lamp and transformer can't draw more than 60 W, as the two impedances in series will be higher than either one alone. This limits the steady state fault current to at worst 0.5 A (120 V like North America) or 0.25 A (for 240 V like Europe).
If you make a mistake and connect the mains across a low voltage secondary, or connect a 120 V primary to 240 V, it is very likely that the transformer will saturate, causing very high current to flow (this is the result of the inductance dropping due to saturation). The lamp limits this current. The lamp is unlikely to light up visibly if there no fault, since the magnetizing current of the transformer will be too low to cause it to glow. If it glows, you have a problem, but not one that will blow fuses or worse.

When using the series lamp, make sure the measure the voltage directly at the primary coil rather than assuming it is at line voltage. Some voltage will be dropped by the lamp. Account for this drop when calculating the secondary voltages. E.g. If the secondary measures 20 V with 200 V measured at the primary, then it will be 24 V with 240 V at the primary.

Note that the lamp helps protect the DUT (the transformer), not you. You still need to take all necessary precautions when working with high voltages (> 50 V or so) or anything capable of delivering high currents. The AC line is both.

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