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### Topic: 3 wire solenoid wiring help (Read 660 times)previous topic - next topic

#### jremington

#15
##### May 28, 2019, 07:28 pm
Important facts from the solenoid data sheet:

Quote
Rated voltage DC: 3V
Action coil resistance: R = 5.7 ± 0.2Ω
Maintain the coil resistance: R = 380 ± 20Ω

#16
##### May 28, 2019, 11:21 pmLast Edit: May 28, 2019, 11:36 pm by docdockstader
Are you familiar with Ohm's law?
I am familiar with Ohm's law, but that's about it.  I know at 3.3 volts and 800mA, the power usage can be up to  two and a half watts, but as I don't have the data sheet for the solenoid, I don't know how much to expect it to use...  I'm sure I'm missing some inference in the question...

#17
##### May 28, 2019, 11:26 pmLast Edit: May 28, 2019, 11:36 pm by docdockstader
Important facts from the solenoid data sheet:
Thanks jremington!  If my very unskilled math is right... at 3.3 volts and a combined minimum resistance of 354.5, I'm only sitting at about 10 milliamps to actuate the armature.  To then hold it open, I'm closer to 9 milliamps.  I have no idea if that's right.... am I on the right path?

OR... maybe I don't combine the resistance, so it'd be 600mA for the action coil, and 9mA for the maintenance coil?  Either way... seems like 800mA will be sufficient for this purpose only?

#### jremington

#18
##### May 29, 2019, 12:08 amLast Edit: May 29, 2019, 12:08 am by jremington
3.3/5.7 = 578 mA for the action coil
3.3/380 = 8 mA holding.

The combined resistance, for parallel resistors, is 1/(1/5.7 + 1/380) = 5.6 Ohms. There is no point in combining them.