Body
Hi Sven,
Based on your measurements here are some calculations:
The theory behind it is here:
https://www.electronics-tutorials.ws/accircuits/ac-inductance.html https://www.electronics-tutorials.ws/accircuits/ac-inductance.html
https://en.wikipedia.org/wiki/Power_factor https://en.wikipedia.org/wiki/Power_factor
https://en.wikipedia.org/wiki/Trigonometry https://en.wikipedia.org/wiki/Trigonometry
Regards
Ole
---In [email protected], <s.friedrich@...> wrote :
Hi Ole, I just could do a simple little power measurement. Both transformers take up 32 to 33 watts active power at 230V operating voltage. the PF is 0.27 to 0.28 for both transformers. Greetings Sven
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Von: "onielsen@... [EVGRAY]"
Datum:26.01.2018 20:51 (GMT+01:00)
An: [email protected]
Betreff: Re: Aw: Re: AW: Re: AW: Re: AW: Re: AW: Re: AW: Re: Re: AW: [EVGRAY] Re: Kone & Hector, you guys finally did it!
Hi Sven,
When you say abused is the insulation all right? If a transformer has a short in a winding this heats the transformer and is seen as active load. Perhaps a scope reading of the voltage and current is needed to see if the load is active or reactive. At no load the voltage and current ought to be shifted by 90 degrees. If putting the readings in x-y mode the display should show a non-tilted ellipse for reactive power. Any tilt is caused by resistance and is active (real) power.
When active power is taken from a transformer the inductance of the primary is reduced by the canceling flux from the secondary.
Regards
Ole
---In [email protected], <s.friedrich@...> wrote :
Hi Ole, I'm surprised that are transformers for 24V forklift chargers, these devices were not cheap. On the one transformer was a nameplate. The transformers are pulse-proof and can deliver 40A at 25.2 volts.
What struck me then when I abused one as a choke that they were eventually warm.
Too little iron for the large winding with large cross-section, I have to understand that!?!
I still have a microwave transformer here, which really has a very bad degree of efficiency at 230 volts, which takes up no load 4390 mA and at 100 volts, the power consumption is twice as high as the other. On the microwave transformer stands for 1100VA although he is much smaller. I just noticed that the MOT has a small magnetic shunt, but does this have any advantages to work as a transformer except that it may not overload it so quickly.
regards
Sven Gesendet: Freitag, 26. Januar 2018 um 18:58 Uhr
Von: "onielsen@... [EVGRAY]" <[email protected]>
An: [email protected]
Betreff: Re: AW: Re: AW: Re: AW: Re: AW: Re: AW: Re: Aw: Re: AW: [EVGRAY] Re: Kone & Hector, you guys finally did it!
Hi Sven,
My guess is that the transformers are made for being cheap. If made for microwave ovens they are only used intermittently at full power thus no problem. For continuous standby use they may be energy consumers if having too much resistance that dissipates the power as heat (active power) or Watts. If the power is pure reactive (VA-reactive) across only some few Ohms of resistance no problem too as very little heat dissipation takes place then. But it does look like some saturation is happening.
Regards
Ole
---In [email protected], <s.friedrich@...> wrote :
Hello Ole,
the differences between the voltages are very different as far as the current consumption is concerned. Actually, one should assume that the transformers should actually behave fairly evenly, at least linearly, the current should increase with increasing voltage. What I particularly noticed is that a transformer is a bit louder than the other or just has a different pitch.
How to tune a transformer so!?! I could imagine that it is synonymous s.der core but there I have no influence on it.
regards
Sven