Power requirements for driving 50 push solenoids

Hello forum!

I’m working on a kinetic sculpture for a museum in Denmark that uses 50 6V (1A) “push solenoids” (Medium Push-Pull Solenoid - 5V or 6V : ID 3992 : $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits) for an installation at a museum using an arduino microcontroller and separate power supplies for group of solenoids (4 solenoids per separate power supply which are rated at 6V, 5 A). I’m using around 13 stackable motor shields (Overview | Adafruit Motor Shield V2 | Adafruit Learning System) to drive the solenoids. All the power sources are rated for both 100-240 V.

Ideally, I’d like to be able to activate the solenoids at the same time during certain parts. I’m assuming that if they were to be triggered at the same time, they could source 50 A. Therefore, the individual sources would have to be distributed to different outlets on separate circuit breakers so as to not trip the breaker. Here in the US, most wall outlets (excluding kitchens) can supply around 15A. I’m not sure about the specific power constraints in Europe or Denmark specifically, but I know that in the UK they typically can provide 13A.

I wanted to see my thinking about this is sound. Also, if you all have any ideas/advice in how I might be able to drive the solenoids without the constraint of the circuit breaker limiting current would be greatly appreciated! Many thanks in advance :slight_smile:

12volt/50Amp is 600watt.
For that, about 700watts is drawn from the mains power (a supply is not 100% efficient).
In the US that would be 700/110= about 6.5Amp drawn from the grid.
In Denmark that would be 700/230= about 3Amp.

H-bridges for solenoids is wasteful. Only part of the driver chip is used.
Stacking 13 shield will not be reliable either.

I'm thinking of driving each solenoid with a logic level mosfet, with port expanders controlling the mosfets.
Not sure if you want to PWM the mosfets/solenoids, to control their power/excursion.
Port expanders only use a few pins of an Arduino. Any small Arduino can be used for that.

Edit: just saw that you are going to use push-pull solenoids. Then H-bridges could be needed.
Leo..

The solenoids you linked are 6V, not 12V, the same size solenoid wound for 12V would draw about 1/2 the current (0.5A) for the same wattage (6), 25A for 50 sols.

You can get avalanche protected Logic level N-Channel MOSFETs for a relative low price. Ratings of 50 amps and more are readily available. You will have to take a look at the size of your wire. What I have done because of distance is use RS485 boards for about a dollar on eBay. The outputs are capable of driving MOSFETs, this will allow you to spread this out. I am assuming it takes more space then a table but maybe several rooms. This response is to help you get started in finding the problem, not solve it for you.
Good Luck & Have Fun!
Gil

Wawa:
12volt/50Amp is 600watt.
For that, about 700watts is drawn from the mains power (a supply is not 100% efficient).
In the US that would be 700/110= about 6.5Amp drawn from the grid.
In Denmark that would be 700/230= about 3Amp.

Thanks for your response and for the clarification - so assuming I can draw 3A from the outlet without tripping the breaker, that means that I won't have to worry about distributing different power supplies to outlets on separate circuit breakers?

gilshultz:
You can get avalanche protected Logic level N-Channel MOSFETs for a relative low price. Ratings of 50 amps and more are readily available. You will have to take a look at the size of your wire. What I have done because of distance is use RS485 boards for about a dollar on eBay. The outputs are capable of driving MOSFETs, this will allow you to spread this out. I am assuming it takes more space then a table but maybe several rooms. This response is to help you get started in finding the problem, not solve it for you.
Good Luck & Have Fun!
Gil

Hi Gil, thank you for your response. Yes, I've heard about using the RS485 boards especially for longer cable runs. Fortunately, for this project all the runs should be less than 10 ft so I think I should be ok.

bradamadra:
I'm working on a kinetic sculpture for a museum in Denmark that uses 50 6V (1A) "push solenoids" (Medium Push-Pull Solenoid - 5V or 6V : ID 3992 : $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits) for an installation at a museum using an arduino microcontroller and separate power supplies for group of solenoids (4 solenoids per separate power supply which are rated at 12 V, 5 A).

Why are you considering a 12V power supply for 6V solenoids?

Either use 12V solenoids or a 6V power supply. I'd go for the first option for less current.

Wawa:
Edit: just saw that you are going to use push-pull solenoids. Then H-bridges could be needed.

The one OP linked to (Medium Push-Pull Solenoid - 5V or 6V : ID 3992 : $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits) states its a regular spring loaded solenoid, push OR pull type, no indication it's push/pull or the need of an H-bridge.

gilshultz:
You can get avalanche protected Logic level N-Channel MOSFETs for a relative low price. Ratings of 50 amps and more are readily available.

OP needs 1A only. Why 50A?

I've also seen you often promoting this "avalanche protection" thing as replacement for a flyback diode. Do post a link explaining how that would work, as I don't see how it possibly could, and links to specific data sheets as I haven't been able to find such a rating.

wvmarle:
Why are you considering a 12V power supply for 6V solenoids?

Either use 12V solenoids or a 6V power supply. I’d go for the first option for less current.

The one OP linked to (Medium Push-Pull Solenoid - 5V or 6V : ID 3992 : $7.50 : Adafruit Industries, Unique & fun DIY electronics and kits) states its a regular spring loaded solenoid, push OR pull type, no indication it’s push/pull or the need of an H-bridge.

Hi, thanks for your response. Yes, I am using 6V supplies, not 12V ones - I made an error in the description of the original post (I’ll update it). And the solenoids are indeed spring-loaded so yes, no need for the H-bridge.

So you'll be looking for a 50A, 6V (or 42A, 5V - those solenoids also work at 5V and that's probably easier to find and the pull is hopefully strong enough for your application) power supply. Downrating is a good idea, so more like 70-80A. More sensible may be 4x20A power supplies.

No need to spread them out over the sockets/groups. 50A 6V = 300W, so less than 3A on 220V. That's no problem for a single outlet.

I do not see a parameter for the time it takes for the solenoid to extend, nor the time it takes to retract, nor the cycle time for any given solenoid. Nor do I see a hold time. All will have an effect on the power supply.

Any solenoid that is rapidly cycled will need a heat sink or a cooling time.

Paul

Paul_KD7HB:
I do not see a parameter for the time it takes for the solenoid to extend, nor the time it takes to retract, nor the cycle time for any given solenoid. Nor do I see a hold time. All will have an effect on the power supply.

Any solenoid that is rapidly cycled will need a heat sink or a cooling time.

Paul

Hi Paul - thanks for your response.

Each solenoid is cycled anywhere between 0.5-3Hz and for a duration of 210ms. Do you foresee any potential problems with overheating with this in mind ?

If that's continuously, there's a risk of overheating. Get a solenoid or two, and try it.

I do have another question: will your solenoids be able to do that fast a movement? 3 Hz, 210 ms - that are high speeds for a solenoid.

bradamadra:
Each solenoid is cycled anywhere between 0.5-3Hz and for a duration of 210ms. Do you foresee any potential problems with overheating with this in mind ?

As @wvmarle has queried, will the solenoid operate at full throw action at those operating frequencies.
As the solenoid is only a PULL type, with a spring to do the PUSH, the spring and the mass of the system you are moving will determine the frequency response of the solenoid system.
Tom.... :slight_smile:

wvmarle:
If that's continuously, there's a risk of overheating. Get a solenoid or two, and try it.

I do have another question: will your solenoids be able to do that fast a movement? 3 Hz, 210 ms - that are high speeds for a solenoid.

When I tested them they were able to be cycled that fast however I never stress tested them for longer periods of time. They do get a little warm to the touch. Also, they aren't being cycled all the time - there are moments where they are inactive for duration of 5-10 seconds every minute or so.

TomGeorge:
As @wvmarle has queried, will the solenoid operate at full throw action at those operating frequencies.
As the solenoid is only a PULL type, with a spring to do the PUSH, the spring and the mass of the system you are moving will determine the frequency response of the solenoid system.
Tom.... :slight_smile:

Hi Tom, thanks for your response. Yes, I'm using the side of the solenoid that doesn't have the spring to get a pushing motion (the solenoid's movable rod/core is exposed on both sides to get both push or pull movement).

When I tested them, they were able to complete the full rated throw (around 0.4") at those cycle frequencies. I also wouldn't need the entire throw length for the motion I require. They are being used to "pull" (via pushing) small triggers that are on hinges that rotate around an axel.

Your heat problem will manifest itself in the copper wire core burning out because the heat generated cannot be dissipated fast enough! The external heat you may feel is just an indicator.

Paul