I have bought a pair of used Hammond 1650 E output transformers. I see on the Hammond website that the colors of mine, and the colors of the wires on the secondary side, on the form on the website are different. The colors of mine are black, black with red markings, green, black with green markings. Mine were manufactured in March 2004. Can anyone help me out there?
Tilbakemelding
Tilbakemelding
Google Oversetter
Attachments
It is on the specification sheet from Hammond but for a very old version, I would find the primary windings and measure the output voltages to determine the output wires or if you own a low Ohm meter, check the resistances.
Shouldn't take more than a few mitutes.
Shouldn't take more than a few mitutes.
Hammond changed the design of their OPT's from two secondary windings to a single tapped secondary in the 2003 - 2005 time period. I have a February 2003 vintage 1608 here and it has 5 secondary wires, so it's the two winding version. None of its wire colors (Black, black - yellow, green, green - yellow, and yellow) match yours. You have 4 wires. There should be continuity between all of them if there is a single secondary winding with multiple taps. The spec sheet that I just downloaded from Hammond for the 1650E makes no sense at all since the DC resistance of the whole winding is less than one of the individual sections. Black is likely the common, or 0 ohm wire as this seems to be the case on all Hammond OPT's. Measuring the DCR from black to each other wire should be able to determine the order of the taps. The lowest DCR from black is 4 ohm, the second lowest is 8 ohm and the highest is 16 ohm. These are low resistances, fractions of an ohm which may be hard to measure with a typical meter.
If this fails to give a clear answer, you can feed a signal from an audio generator or other AC source in the audio range into the primary and measure the AC voltage on each tap using the black wire as the common. Here in the US, I have been known to plug the entire primary winding into line power and measure the secondary voltages. We have 120 volts at 60 Hz. 230 or more volts at 50 Hz might be too much for a small OPT to eat, so I would not recommend that, but you could use a lower voltage AC source, say 24 volts or so from a small transformer.
Note that during the changeover period (2003 to 2005) Hammond did use some odd color choices, and even shipped some miswired transformers. I got a 1628SE with the plate and UL wires switched in 2005. Since 2006 I have only seen Black, Green, Yellow, White secondary wires on their OPT's.
If this fails to give a clear answer, you can feed a signal from an audio generator or other AC source in the audio range into the primary and measure the AC voltage on each tap using the black wire as the common. Here in the US, I have been known to plug the entire primary winding into line power and measure the secondary voltages. We have 120 volts at 60 Hz. 230 or more volts at 50 Hz might be too much for a small OPT to eat, so I would not recommend that, but you could use a lower voltage AC source, say 24 volts or so from a small transformer.
Note that during the changeover period (2003 to 2005) Hammond did use some odd color choices, and even shipped some miswired transformers. I got a 1628SE with the plate and UL wires switched in 2005. Since 2006 I have only seen Black, Green, Yellow, White secondary wires on their OPT's.
I ran into this same thing recently. https://www.application-datasheet.com/pdf/hammond-manufacturing/1628se.pdf
