# Re: MOT Testing

• To: tesla@xxxxxxxxxx
• Subject: Re: MOT Testing
• From: "Tesla list" <tesla@xxxxxxxxxx>
• Date: Sat, 30 Apr 2005 21:51:34 -0600
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`Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>`

Tesla list wrote:
Original poster: "Paul B. Brodie" <pbbrodie@xxxxxxxxxxxxx>

My math background includes college calculus and I am familiar with complex numbers. I hate phasor diagrams, they give me a headache! I very much understand inductive reactance. Your explanation is very difficult to follow because you refer to the inductive reactance as ohms when I think you are meaning henries. If you say 1 ohm of inductance, do you mean that the resistance you are dealing with at the 60 Hz mains frequency for the inductance of the particular inductor you have is 1 ohm? If so, then the resistance is indeed 1 ohm and the 1 ohm of the resistor can be added with the 1 ohm of the inductor to get 2 ohms of resistance, in this circuit at this frequency. So, if we the equation for determining the resistance of an inductor, 2*pi*f*L, at mains 60 Hz, we get your 2.6mH inductor. If I put that inductor in series with a 1 ohm resistor and measure the resistance, I will get 2 ohms.

This is not correct. Reactance is really measured in Ohms. It is
the ratio of voltage over current for sinusoidal signals (use peak
or rms values) for reactive impedances (inductors and capacitors).
1 Ohm of reactance added to 1 Ohm of resistance add as:
Z = 1 + j, where j=sqrt(-1). This is just a representation using
the fact that for sinusoidal signals the current in an inductor is
always delayed by 90 degrees, that means that the current is delayed
in relation to the voltage by the angle of the complex number (45 degrees), and that the absolute value of the impedance is 1.4142 (sqrt(2)) Ohms.

`Antonio Carlos M. de Queiroz`