OK so here's the latest measurements, I copied the table outline above. The figures recorded are the most stable during any fluctuations.

	black	white	blue	yellow
black		0.6	0.3	0.2
white	0.6		0.7	0.6
blue	0.3	0.7		0.3
yellow	0.2	0.6	0.3

 

UNITS?? Are those volts or ohms??
For production transformers the wire sizes for different windings is very common. Even in the cheap junk doorbell transformers, the primary and secondary are different wire sizes.

 

We asked for AC voltage readings this time around, not resistance readings.

 

Twp reasons for using voltage readings instead of resistance measurements: First, the no-load voltage reading is an absolute indication of turns ratio,at least in a transformer with no short-circuited turns, and also, because most multi-meters have rather poor resolution for very low resistance measurements. That is verified by the one-digit resistance readings in the supplied table.
For accurate low resistance measurements a four-terminal ohm-meter is usually required.

 

Ok here's the requested voltage info, all VAC readings based of a 21.45vac input:

	black	white	blue	yellow
black		2.79	9.16	17.09
white	2.79		2.14	2.42
blue	9.16	2.14		16.67
yellow	17.09	2.42	16.67

 

Which wires were connected to the input, because I can't make any sense of the results?

 

UNITS?? Are those volts or ohms??
For production transformers the wire sizes for different windings is very common. Even in the cheap junk doorbell transformers, the primary and secondary are different wire sizes.

I understood that we are trying to figure out the taps on a single primary winding, which should be all the same gauge wire. Mentioning the effect of different gauge wire on different windings is just confusing the issue.

 

Which wires were connected to the input, because I can't make any sense of the results?

I don't think I understand.. those VAC values were from a 21.45vac on each of the mentioned primary pairs.

The issues I had was which primary pairs were used for what, and why the blue and yellow leads (in combination with black) cannot accept 120vac without threatening to blow a breaker.

Like this latest set, I can send almost 22 volts to black/yellow but if I try 120 it wants to melt down. Is that perhaps because of that winding having a lower amount of resistance than black/white does?

I feel like I'm not able to verbalize a lot of this to the degree that you guys are used to.

 

Do you have a low voltage AC source, lower than 6VAC?
Apply low voltage AC across the secondary winding.

 

Do you have a low voltage AC source, lower than 6VAC?
Apply low voltage AC across the secondary winding.

Lower than 6.. no I don't think so. I'll look through my stuff though and make sure. What will a sub-6vac on the secondaries show?

 

The secondary winding will be for charging the batteries, so it will take more than 6V. Connect your 21VAC source across the secondary and then measure the voltages between each pair in the primary. Be careful though, some of the voltages will probably be quite high. Shorting them together could cause damage and touching them could be painful!

Procedure:
1. Connect the AC voltmeter to a pair of wires on the primary.
2. Connect the AC voltage source to the secondary.
3. Record the voltage.
4. Disconnect the AC voltage source from the secondary.
5. Repeat 1 through 4 for every possible pair of wires on the primary..

That will give us the position of the taps on the primary and the voltage ratios between them..

 

The secondary winding will be for charging the batteries, so it will take more than 6V. Connect your 21VAC source across the secondary and then measure the voltages between each pair in the primary. Be careful though, some of the voltages will probably be quite high. Shorting them together could cause damage and touching them could be painful!

Procedure:
1. Connect the AC voltmeter to a pair of wires on the primary.
2. Connect the AC voltage source to the secondary.
3. Record the voltage.
4. Disconnect the AC voltage source from the secondary.
5. Repeat 1 through 4 for every possible pair of wires on the primary..

That will give us the position of the taps on the primary and the voltage ratios between them..

Ok here it is, 21.45vac applied to secondary leads:

	black	blue	white	yellow
black		40.52	134.0	20.30
blue	40.52		175.3	20.29/30
white	134.0	175.3		155.0
yellow	20.30	20.29/30	155.0

The .29/30 signifies a constant fluctuation between the two, and of course all values are in VAC. Back in the day I caught a full T1's 130vdc twice back to back. After the second time my thumb quit working for a while, lol. So I try to be careful after that.

 

This time the numbers add correctly. I have rounded the numbers in order to keep it simple.
If you treat the input on the secondary as being 20VAC, then divide the numbers shown in the table below by 20 to give the turns ratio with respect to the secondary winding.

For example, blue-yellow is 20:20, blue-black is 40:20, blue-white is 175:20.
White-black is 135:20.

	Blue	Yellow	Black	White
Blue	0	20	40	175
Yellow	20	0	20	155
Black	40	20	0	135
White	175	155	135	0

 

Now we have some good data, this is how the transformer is wired:

 

Am I understanding correctly, due to the winding size/turns, is why blue/yellow can't handle 120v?

 

Am I understanding correctly, due to the winding size/turns, is why blue/yellow can't handle 120v?

Correct. There are not enough turns between blue and yellow.

 

Correct. There are not enough turns between blue and yellow.

So what happens in an electrical sense in this? Too few turns means not enough electromagnetic field/flux being generated which then means... ?

 

Too few turns means that the inductance is low, which means that the reactance is low.
Reactance of an inductor is calculated using the formula:

XL = 2πfL

where,
XL = reactance (ohm)
f = frequency (Hz)
L = inductance (henry)

 

Too few turns means that the inductance is low, which means that the reactance is low.
Reactance of an inductor is calculated using the formula:

XL = 2πfL

where,
XL = reactance (ohm)
f = frequency (Hz)
L = inductance (henry)

Much appreciated!

 

Which wires were connected to the input, because I can't make any sense of the results?

I see about 21.