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solenoid valve control (using RC-4 and Crydom relays) — Parallax Forums

solenoid valve control (using RC-4 and Crydom relays)

TintinTintin Posts: 37
edited 2007-08-08 16:31 in BASIC Stamp
Hi,

I am looking into controlling a 120Vac solenoid valve with a coil rating of 8W, 25VA (in rush) and 14.5VA (hold).· Would the Crydom·D2W203F·rated at 3A of load current be appropriate for the application?··From my·understanding,·there would be a max reactive current of·25/120 = 0.21A and
0.066A real current·so the use of·such relay would be OK.· Any confirmation/correction·of this reasoning would greatly be appreciated!

Frank······

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2007-08-08 15:18
    Sounds good to me. Keep in mind that the 3A rating of the SSR is steady-state. I don't remember what the peak rating is, but I suspect it's much higher for a couple of half-cycles of the AC.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2007-08-08 16:31
    Frank,

    The VA ratings are not the current in amps being drawn. VA (Volt Amps) is really equivalent to Watts for the most part (with some exceptions). So if you calculate the 8W rating you gave @ 120VAC you would normally see .07A of current. The VA accounts for apparent power from an AC source and so you can expect the current to be roughly .21A, still well below the rating of the SSR. I hope this helps. Take care.

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    Chris Savage
    Parallax Tech Support
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