Bought a surplus toroid transformer, labeled:
Definitive Technology
P/N 0072A100
OBJY2 JEC 105
REF# 15-0070
31/96
120v pri/42v ct
secondary voltage when powered 45.3v and 22.81v -0- 22.85v
secondary resistance 1.5 ohms and 1.2 ohms -ct- 1.1 ohms
primary resistance 6.1 ohms
Dimensions are 4.5" wide by 2" high, center hole is 2" wide
I have Dale load resistors, how do I calculate maximum va load?
4- NH-25-19 (25w .01ohm -3+7%)
2- NH-50-31(50w .1ohm 3%)
7- NH-50-25(50w 4ohm 3%)
6- NH-50-25(50w 15ohm 3%)
4- NH-50-121(50w 5Kohm 10%)
Can someone help me calculate primary and seconday fuse sizes?
Thanks Phil
Definitive Technology
P/N 0072A100
OBJY2 JEC 105
REF# 15-0070
31/96
120v pri/42v ct
secondary voltage when powered 45.3v and 22.81v -0- 22.85v
secondary resistance 1.5 ohms and 1.2 ohms -ct- 1.1 ohms
primary resistance 6.1 ohms
Dimensions are 4.5" wide by 2" high, center hole is 2" wide
I have Dale load resistors, how do I calculate maximum va load?
4- NH-25-19 (25w .01ohm -3+7%)
2- NH-50-31(50w .1ohm 3%)
7- NH-50-25(50w 4ohm 3%)
6- NH-50-25(50w 15ohm 3%)
4- NH-50-121(50w 5Kohm 10%)
Can someone help me calculate primary and seconday fuse sizes?
Thanks Phil
Attachments
you can probably tell more about the transformer by examining the size (guage) of the wires in the primary and secondary side --
testing the transformer by loading it -- you should measure the heat rise in the core with various loads --
did Definitive use this in one of their speaker amplifiers? -- should give you a clue.
testing the transformer by loading it -- you should measure the heat rise in the core with various loads --
did Definitive use this in one of their speaker amplifiers? -- should give you a clue.
Wire gauge, nah, I can't see windings through wrapper.jackinnj said:
Unfortunately don't want to damage wrapper to check this.
jackinnj said:
I believe this data on label is spec and temperature- OBJY2 JEC 105. My guess is it's laquer rating is 105F above abient temperature. Maybe someone knows better.
Definitive Technology website doesn't seem to have amps.jackinnj said:
after you find out how much it weighs you could compare it to the weights of plitron's toroidal transformers (or another company that has this info. published).
here's plitron's info.
here's plitron's info.
The 2" hole suggests more a 300VA.
I found that manufacturers generally give higher dimension specs than the real, probably like some slack.
Overhere 42vac is a standard size for 300va's , not for 250's, 225's or lower.
A 300 is sized at 4.75" but in reality is 4.5"
Up till 300va 1kg/100va is fairly accurate(+50grams for the smaller of size).
Between 425va and 800va the factor is 0.8 kg/100va.
From 1000va it drops to 0.75 kg/100va and lower.
i did some dimension analysis of toroids long ago(for fun).
The spread then was higher between manufacturers(here).
Copper and steel price for toroid wiring and cores have gone up quite considerable, and competition in the toroid business is pretty steep.
Toroids nowadays are made much more with economics in mind.
But i am very curious if it is a 5.0 or a 6.5 pounder.
I found that manufacturers generally give higher dimension specs than the real, probably like some slack.
Overhere 42vac is a standard size for 300va's , not for 250's, 225's or lower.
A 300 is sized at 4.75" but in reality is 4.5"
Up till 300va 1kg/100va is fairly accurate(+50grams for the smaller of size).
Between 425va and 800va the factor is 0.8 kg/100va.
From 1000va it drops to 0.75 kg/100va and lower.
i did some dimension analysis of toroids long ago(for fun).
The spread then was higher between manufacturers(here).
Copper and steel price for toroid wiring and cores have gone up quite considerable, and competition in the toroid business is pretty steep.
Toroids nowadays are made much more with economics in mind.
But i am very curious if it is a 5.0 or a 6.5 pounder.
I've been holding off weighing my toroid transformer because I was expecting delivery of another toroid this weekend. It arrived, I'll be weighing them this week.
In the mean time of have a wiring question. The newer toroid has dual primary coils and two sets of center tap secondaries. See pic for info and note lead gauges.
Is it better to wire primaries in series or parallel?
It appears better for me to wire 120 volt primaries in series, the blue lead are 18 gauge and suggests it could handle more current.
Is there a problem with this?
What fuse sizes would you suggest?
Thanks Phil
In the mean time of have a wiring question. The newer toroid has dual primary coils and two sets of center tap secondaries. See pic for info and note lead gauges.
Is it better to wire primaries in series or parallel?
It appears better for me to wire 120 volt primaries in series, the blue lead are 18 gauge and suggests it could handle more current.
Is there a problem with this?
What fuse sizes would you suggest?
Thanks Phil
Attachments
Meaning:
the output voltage of a transformer is determined by the ratio of primary and secondary winding.
Put two 120v windings in series;
>> twice the number of windings
>> twice the ratio
>> output voltage on the secondary is half of that when two primaries are in parallel.
Put the 2 120v primaries in series and place 240v on the primary.
>> twice the voltage>> primary resistance is twice>> same current>> 240*A = 120*A + 120*A.
the output voltage of a transformer is determined by the ratio of primary and secondary winding.
Put two 120v windings in series;
>> twice the number of windings
>> twice the ratio
>> output voltage on the secondary is half of that when two primaries are in parallel.
Put the 2 120v primaries in series and place 240v on the primary.
>> twice the voltage>> primary resistance is twice>> same current>> 240*A = 120*A + 120*A.
Hi jacco vermeulen,
This toroid is more usable to be wiring primary coils in series (see pic). 24-0-24 volt secondary for gainclone and 8-0-8 volt secondary for preamp.
How will wiring primary coils in series effect va output?
Will va go up or down with primary in series?
What would fuse sizes be this way?
This toroid is more usable to be wiring primary coils in series (see pic). 24-0-24 volt secondary for gainclone and 8-0-8 volt secondary for preamp.
How will wiring primary coils in series effect va output?
Will va go up or down with primary in series?
What would fuse sizes be this way?
General transformer estimating question: While you can't see the gauge of the windings, couldn't you use the gauge of the primary and secondary leads as a guide to determining the current limit? Or do their short length make this more difficult?
Not sure how much impact it has on weight, but Plitrons have the core filled with epoxy so they will weigh somewhat more.
Not sure how much impact it has on weight, but Plitrons have the core filled with epoxy so they will weigh somewhat more.
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