I have a system where I want to power 4 solenoids in line with a 4 channel relay module connected to an arduino uno.
The factory info says the solenoids use 12VDC 2.5A each but what happens when is an array of 4 solenoids in line.
Which power supply should I use?

thanks in advance

 

The factory info says the solenoids use 12VDC 2.5A each

That seems like a lot. What do the solenoids do? Have you looked for lower power variants?

but what happens when is an array of 4 solenoids in line

Does "in line" mean connected to the same power source?

Which power supply should I use?

1. Are the relays 5V?
2. What are their loads and supply voltage(s)?
3. Do you intend to have the coils on the Arduino power supply?

 

These are the solenoids, I have 4 of them and where somehow expensive so I would like to use them
note: one user in the review says they are really taking 5A of current:
Hechen JF-1264B DC 12V 500mA 55N 10mm Hub Push Pull Type Open Frame Door Lock
LINK: https://www.amazon.de/dp/B07M7T6WFQ?psc=1&ref=ppx_yo2ov_dt_b_product_details

Yes, by "in line" I meant connected to the same power source

1. Are the relays 5V? YES

1. What are their loads and supply voltage(s)? Of the relays?
2. Do you intend to have the coils on the Arduino power supply? NO, it is with an external power supply, I order one that is 12VDC 5A, but I wanted to ask here first if that could be enough

 

These are the solenoids, I have 4 of them and where somehow expensive so I would like to use them

Where did you get 2.5A? The listing says 0.5A.

I didn't read any of the reviews, but I wouldn't necessarily trust them.

What are their loads and supply voltage(s)? Of the relays?

Yes. What are the relays switching?

Do you intend to have the coils on the Arduino power supply? NO, it is with an external power supply, I order one that is 12VDC 5A, but I wanted to ask here first if that could be enough

That should be more than sufficient for the solenoids, but you haven't described what the relays will be switching.

 

Where did you get 2.5A? The listing says 0.5A.

And on the solenoid itself, it says 2.5A.

That should be more than sufficient for the solenoids, but you haven't described what the relays will be switching.

I think we can infer that the four relays are switching the four solenoids.

 

Where did you get 2.5A? The listing says 0.5A.

This is written in the solenoid itself


Nevertheless a user states in a revoew that is really 5A????


The relays are switching the 4 solenoids


all the best,
Jul

 

This is written in the solenoid itself

The seller made a pretty big mistake if that's the case. It looks like an attempt was made to change the current requirement on 3 of the 4 solenoids. Are these the ones you purchased?

Nevertheless a user states in a revoew that is really 5A????

Still don't trust them. It could have been the power supply they were using and whatever else it was powering.

If the solenoids are really 2.5A, then you need at least a 10A power supply. If you can guarantee that they won't all be on at the same time, you could use a smaller power supply.

Will the solenoids be activated continuously? Or intermittent? There are ways to decrease power used by the solenoid coils by taking advantage of the lower sustaining current.

 

Will the solenoids be activated continuously? Or intermittent? There are ways to decrease power used by the solenoid coils by taking advantage of the lower sustaining current.

The project uses 4 pots that are controlling the triggering rate time of the 4 solenoids respectively (with relays). That is to say, there will be times when all 4 solenoids coincide and are being activated at the same time. The idea is to have the solenoids playing percussion instruments. So you can vary the time rate of the strokes in real time with the pot knobs, each of the solenoids having an individual time.

 

That is to say, there will be times when all 4 solenoids coincide and are being activated at the same time.

If it was my project, I'd look for solenoids that took less power. Do you actually need the 55N holding force?

Here's a circuit designed by Bob Pease and redrawn by Paul Rako (I never saw a schematic from Bob that I'd consider readable):

Your relay contacts would replace Q1. There are 2 snubber diodes across the solenoid coil because there needs to be sufficient voltage when the solenoid is switched off to turn on Q2 to discharge C1. If you don't do this, the capacitor won't discharge and subsequent activations wouldn't apply enough voltage across the solenoid coil for it to pull-in.

Pease assumed that the solenoid would sustain with about 2/3 of the nominal coil voltage. R2 needs to be a power resistor. The combination of C1 and R2 give the time constant for how fast the coil voltage is reduced.

With a current of 2.5A, your coil resistance would be 4.8Ω so you'd need a 3.9Ω power resistor for R2 (10W minimum, maybe larger depending on your duty cycle).

If you used a less power hungry solenoid, the size of C1 wouldn't be as much of an issue. By itself, it consumes 30W. With the power reducing circuit, it drops to 17W for the coil+R2.

You should check my math.

Specs from https://heschen.com/products/hechen-solenoid-electromagnet-hs-1264b

 

If it was my project, I'd look for solenoids that took less power. Do you actually need the 55N holding force?

Here's a circuit designed by Bob Pease and redrawn by Paul Rako (I never saw a schematic from Bob that I'd consider readable):
View attachment 302359
Your relay contacts would replace Q1. There are 2 snubber diodes across the solenoid coil because there needs to be sufficient voltage when the solenoid is switched off to turn on Q2 to discharge C1. If you don't do this, the capacitor won't discharge and subsequent activations wouldn't apply enough voltage across the solenoid coil for it to pull-in.

Pease assumed that the solenoid would sustain with about 2/3 of the nominal coil voltage. R2 needs to be a power resistor. The combination of C1 and R2 give the time constant for how fast the coil voltage is reduced.

With a current of 2.5A, your coil resistance would be 4.8Ω so you'd need a 3.9Ω power resistor for R2 (10W minimum, maybe larger depending on your duty cycle).

If you used a less power hungry solenoid, the size of C1 wouldn't be as much of an issue. By itself, it consumes 30W. With the power reducing circuit, it drops to 17W for the coil+R2.

You should check my math.

Specs from https://heschen.com/products/hechen-solenoid-electromagnet-hs-1264b
View attachment 302360

Thanks for your time,
I'm going to check all this carefully because clearly I don't understand electronics very well.

 

I'm going to check all this carefully because clearly I don't understand electronics very well.

I think your best option would be to find lower power solenoids because you'll probably be cycling them too fast for the power saving circuit to work; and you'd need four of them.

Not understanding electronics very well isn't a problem as long as you can learn.

 

Do you have a clue how much force and how long a stroke you need? How did you pick these in the first place? 55N is over 12 lbs. If you don’t need that kind of pull, you can find solenoids that use lower current.

 

Thanks, I'm realizing that I bought some solenoids that are too big for what I want, I'm going to rethink things

 

If the intention is to be able to operate four solenoids at the same time, with each requiring .5 amps, then the minimum power supply capability must be ten amps.

 

55 Newton is a pretty big force. You haven’t mentioned your application, but if you don’t need that much have you tried the solenoids at a lower voltage? They may actuate at as low as 5V. The specification says 2.5A but then says 12/24V so maybe your 5A is the current atv24V?

A lower voltage will reduce your overall current and avoid overheating

 

If you know the required force, and it is less than the 55N, it might work to operate the solenoids in series, except that I think individual control is the plan. OR just pick a lower voltage, that will give less force and draw less current.

 

@pirlem : Simply measure the coil resistance in order to calculate the current.

 

Certainly you can power the solenoids with a lower voltage and they will draw less current. And the force will be less.
The rating is 1/24 volts, but it is not stated which voltage requires the 2.5 amps.
They will also deliver a fair amount of force with only 5 volts. So the very first step is to learn just how much force the application requires. Then the voltage can be determined, and the current calculated. Then a cost effective driver circuit can be designed.