DIYbanter - View Single Post - Lead-free solder is such a PITA (rant/whinge)

Ralph Mowery

In article ,
says...

On Fri, 09 Sep 2016 16:09:10 +0800, pedro wrote:

On Thu, 08 Sep 2016 08:17:12 -0700, Jeff Liebermann
wrote:

What do you measure for coil DC resistance?

Missed that bit. Around 1600 ohms.

Assuming 240VAC, that's:
P = E^2 / R = 240Vrms^2 / 1600 = 36 watts
That's way too high dissipation for a solenoid valve.
Are you sure those are 240VAC solenoids and some other AC voltage? Are
the solenoids run by 240VAC or some other voltage?

Also, could you check the eBay listing number? I want to see the coil
specs. Nothing found:
http://www.ebay.com/sch/i.html?_nkw=322017672259

Jeff I think you are mixing up the AC and DC power formulas.

I am sure the impedance of the coil at 60 Hz is more than the DC
resistance.

That would make the wattage less than what you have calculated using a
DC equation.

A quick check of the Goyen catalog shows they draw about .05 to .07 Amps
depending on the coil at 240 volts.
That is around 10 to 16 watts. The DC resistance of the coils was not
given. The coils on many of the valves can be changed to several
voltages.