hi guys,
i have a toroidal rated at 500watt
there are 4 output secondary:
0-48 0-48
0-36 0-36
0-24 0-24
0-18 0-18
assuming Watt=Volt x Ampere,
so if calculating from
48v > 500watt/2x48=5,2A
36v > 500watt/2x36=6,9A
24v > 500watt/2x24=10,4A
18v > 500watt/2x18=13,9A
does anyone know how to calculate properly?
i mean, what is the real current for 500watt toroidal transformer?
thanks.
i have a toroidal rated at 500watt
there are 4 output secondary:
0-48 0-48
0-36 0-36
0-24 0-24
0-18 0-18
assuming Watt=Volt x Ampere,
so if calculating from
48v > 500watt/2x48=5,2A
36v > 500watt/2x36=6,9A
24v > 500watt/2x24=10,4A
18v > 500watt/2x18=13,9A
does anyone know how to calculate properly?
i mean, what is the real current for 500watt toroidal transformer?
thanks.
With multiple secondaries you can't tell, as there is no easy way of determining exactly how the designer apportioned his available VA among them. You may be able to get a rough idea by measuring their resistance - but measuring low resistances accurately is not easy.
I would say more likely like this (rough estimate)
0-48 0-48, 5A (x2)
0-36 0-36, 3A
0-24 0-24, 2A
0-18 0-18, 1A
0-48 0-48, 5A (x2)
0-36 0-36, 3A
0-24 0-24, 2A
0-18 0-18, 1A
You are mixing Watts and Volt-Amps as if they were the same, they are certainly not. You must consider power factor. If you feed an AC winding into a full wave bridge, the DC load current available is only about 0.6 times the AC RMS current rating of the transformer secondary.
BTW:
Impossible. The transformer can not be rated in watts, it is V-A.
Electric power transformer is specified in VA (apparent power = volts X amps). Depending on the rectifier used, the DC power available is much less than the apparent power.
a) if the four windings of the transformer isn't separated galvanically, then winding rated current is calculated as follows:
I = Power / Voltage = 500 / (2 x 48) = 5.20 amps.
So, in such a case, all the windings of the transformer can be loaded with a maximum of 5.20 amps. To learn if the transformer is in this situation, you must measurement all sections winding conductors. If sections conductors are identical, then you are in this case, if not, see case b below.
b) This case applies when the windings are galvanically separated. Measurement section conductors can provide us an idea about the current values that can be charged by them, with the condition that relate to a certain current density (eg 3A/mmp). I can make you a concrete answer to this question but you need tell me the diameter of each winding conductor.
a) if the four windings of the transformer isn't separated galvanically, then winding rated current is calculated as follows:
I = Power / Voltage = 500 / (2 x 48) = 5.20 amps.
So, in such a case, all the windings of the transformer can be loaded with a maximum of 5.20 amps. To learn if the transformer is in this situation, you must measurement all sections winding conductors. If sections conductors are identical, then you are in this case, if not, see case b below.
b) This case applies when the windings are galvanically separated. Measurement section conductors can provide us an idea about the current values that can be charged by them, with the condition that relate to a certain current density (eg 3A/mmp). I can make you a concrete answer to this question but you need tell me the diameter of each winding conductor.
Don is right.
You must check if there is:
one winding with lots of taps
or
two windings with lots of taps
or
many windings with no intermediate taps.
Can you see thickness of the wire in each tap and end?
This can be a good guide to current rating.
You must check if there is:
one winding with lots of taps
or
two windings with lots of taps
or
many windings with no intermediate taps.
Can you see thickness of the wire in each tap and end?
This can be a good guide to current rating.
I agree with previous posts. check wether it is one winding with several taps or wether it is separate windings.
measure thickness to get an idea about current handling. forget about resistance measurment unless you have a low R meter.
measure thickness to get an idea about current handling. forget about resistance measurment unless you have a low R meter.
hi... thanks for comment.
this is the sample pictures of toroidal i mean.
this one rated 500W
with multiple secondary
diameter 14cm height 8cm
weight 4kg
what do you think.?
this is the sample pictures of toroidal i mean.
An externally hosted image should be here but it was not working when we last tested it.
this one rated 500W
with multiple secondary
diameter 14cm height 8cm
weight 4kg
what do you think.?
No you don't.wengtech said:
You have a transformer with two secondaries:
47-32-24-18-0-18-24-32-47
and
18-15-0-15-18
If the wires are all the same size then you have 94V and 36V, so 500VA means 3.85A per secondary. You may be able to draw slightly more from one winding provided you draw much less from the other one, so the total heat generated remains the same.
df96:
i am taking a similar picture from internet, not mine.
(same power rating and same brand, and this kind is very common to my country)
my point is, because of this transformer have multiple secondaries
which one should be the standard voltage for measuring the current.
the highest one (47v) or the lowest one (18v) should be the standard?
about the 18-15-0-15-18
this one is the extra outputs, commonly rated at 1A only.
(for supplying the fan, protectors, etc.) so this one is separated.
i am taking a similar picture from internet, not mine.
(same power rating and same brand, and this kind is very common to my country)
my point is, because of this transformer have multiple secondaries
which one should be the standard voltage for measuring the current.
the highest one (47v) or the lowest one (18v) should be the standard?
about the 18-15-0-15-18
this one is the extra outputs, commonly rated at 1A only.
(for supplying the fan, protectors, etc.) so this one is separated.
Sorry. It didn't occur to me that you would post a picture of a transformer which isn't your one.
We are back to where we started. You can't tell. The best you can manage is a rough estimate, provided you can accurately measure small resistances.
We are back to where we started. You can't tell. The best you can manage is a rough estimate, provided you can accurately measure small resistances.
Read again what I said before. I asked you to tell me all the winding diameter. Are you sure all transformer windings are constructed with 1mm diameter wire? If so, then the case "a", that I just described, is your answer.
Hi,
It has two centre tapped windings, most likely :
A high current winding with +/- 47, 32, 24, 18 V taps
A low current winding with +/- 18, 15 V taps.
rgds, sreten.
It has two centre tapped windings, most likely :
A high current winding with +/- 47, 32, 24, 18 V taps
A low current winding with +/- 18, 15 V taps.
rgds, sreten.
if you have seperate high current and low current output, and its rated at 500VA ... I would guess it covers both outputs running at their highest voltage
running either of them at lower voltage lowers output because they are tapped
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