Sizing a power supply

[[email protected]]

I need to power a water valve actuator with 24AC 650 mA. I cannot
easily find a 650mA 24VAC supply, but 1amp or 2amp or so I can find.

Will the actuator adjust to the amperage it needs? Should I step down
the amperage to 650mA using some sort of current limiting device?

Sorry for the bsaic question, but I want to buy the right parts.

Thanks,

Carl
[email protected]

 

[CWatters]

I need to power a water valve actuator with 24AC 650 mA. I cannot
easily find a 650mA 24VAC supply, but 1amp or 2amp or so I can find.

Either should work fine.

The current rating of a power supply is usually a maximium rating that the
load must not exceed. eg the 1A model can supply 24VAC at upto 1A. The load
only requires 0.65A so it's ok.

 

[tlbs]

Since you need 24 VAC, and not DC, a simple step-down transformer will
work. You do not need a DC power supply. RadioShack has 25.2 VAC 2
Amp (Cat # 273-1512) transformer available that will work just fine.
It's what I use on my sprinkler system at home.

What CWatters says is true -- the actuator will only draw as much
current as it needs. You can't "force" 2 Amps down the line (at 24
Volts or even 25.2 Volts). If the transformer is rated for 2 Amps, all
that means is that you could power up to 3 actuators simultaneously.


(PS: I am not a RadioShack salesperson, or associated with RS -- just
trying to be helpful.)