# I guess I don't understand Rain Bird panel - valve hum & transformer hot

Discussion in 'Irrigation' started by gdeangel, May 20, 2013.

1. ### KirilLawnSite Fanaticfrom District 9 CAMessages: 18,334

That is not a vector diagram.

2. ### Wet_BootsLawnSite Fanaticfrom metro NYCMessages: 50,268

Well, it is a diagram, and it does display the vector quantities of resistance and reactance, as relates to solenoid operation. Besides, making the points on vectors in a diagram takes too much time.

I'm way out of date on a lot of electronics terminology. Wiki searching showed me the inverse of ohm is now 'siemen', as opposed to 'mho' (a term I always liked, besides being a great scrabble word)

3. ### irrig8rLawnSite Platinum Memberfrom Silicon Valley, CAMessages: 4,553

Did you replace the back panel in the box? I got a few of those through my distributor but only encountered it maybe three times. there was an RB technical bulletin that addressed it thoroughly.

5. ### Wet_BootsLawnSite Fanaticfrom metro NYCMessages: 50,268

I could expect no less from a true Magnet Boy, but nothing on that page you linked has anything to do with the electrical characteristics of a solenoid powered by 24 volts AC

6. ### KirilLawnSite Fanaticfrom District 9 CAMessages: 18,334

A solenoid is a helical coil of wire wound round an insulating cylinder. We can find the magnetic field due to a solenoid carrying a steady current I as follows.

Explain how it doesn't relate ... in mathematical terms.

7. ### Wet_BootsLawnSite Fanaticfrom metro NYCMessages: 50,268

Not very relevant to measuring 30 ohms DC resistance in a solenoid coil, and then observe it displaying an impedance of 120 ohms with a 60 Hz voltage applied. My homemade diagram showed how the DC resistance and the AC reactance combine to give the total impedance. Feel free to make a superior impedance diagram.

8. ### KirilLawnSite Fanaticfrom District 9 CAMessages: 18,334

Why is it not relevant? Is it not the purpose of a solenoid to generate a magnetic field?

I asked you for the math, but more to the point, explain how one might go about doing this in the field. Further, explain how this applies to an AC solenoid, once again, mathematically.

You mean a phasor diagram?

9. ### Wet_BootsLawnSite Fanaticfrom metro NYCMessages: 50,268

Since there isn't any appreciable capacitance in the solenoid circuit, the diagrams and equations can be a lot simpler. I will add some half-points to the three vector quantities, and, because it matters not in sprinkler work, I'll leave out the phase angles.

10. ### KirilLawnSite Fanaticfrom District 9 CAMessages: 18,334

No explanation, and no math.