I just bought 22 of these solenoids:
I need a power supply, but new to electronics. Not sure how to calculate the amps I need, etc... I know this is really basic, but any help would be appreciated. I will be plugged in 110volts socket we have in Canada.
If my thinking is right, I just get one power supply and run wires to all solenoids? Is that right. ( I have a relay system in between to shut them off and on, so I know how to do that circuit). Just not clear on how to power them.
Each solenoid is rated for 24 V and has a coil resistance of 77 Ohms. So, it will draw 24 V/77 Ohms = 0.31 amperes of current when energized.
Multiply 0.31 times the maximum number of solenoids that will be energized at any one time to get the total current draw.
24V 10A supply sounds right, or 24V lead acid accumulator, or 6S LiPo pack.
28V nominal means designed for operation from 24V lead acid, as that's the max charging
voltage of such a battery. They should be fine at 24 or 22V. The worst case current draw
is about 7A each. They are designed for continuous duty only with some heatsinking, if you
read the datasheet carefully.
Ok, I was wondering jremington said 24v when the specs read 28 vdc, but I guess markT answered that.
jremington talks about .3amp draw and then markT you say worse case 7amp draw. That seems a huge difference.
That's because Mark was looking at all current of 22 solenoids being driven together.
Say your supply is 28 volts and solenoid resistance is 77.4ohms then individual current is 0.36amps, so for all 22 solenoids driven the total load current is 22x0.36 = 7.95amps
One thing you have to be aware of is the inductive spike you'll get when you release all these solenoids. Your control device (relay of mosfet) will require a surge suppressor/flywheel diode to control the spike.
As to a power supply, something like one of these might meet your needs :
http://www.ebay.co.uk/itm/DC-12V-24V-5V-Universal-Regulated-Switching-Power-Supply-for-LED-Strip-CCTV-UK-/291087849273
No a small free-wheel diode is enough for 0.3A. Each solenoid needs its own diode if driven
independently, but if paralleled you could use one 10A diode for all of them.