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Topic: Can Arduino power 12v 5amp actuator  (Read 1 time) previous topic - next topic

Vinniex1

#15
May 20, 2015, 11:55 am Last Edit: May 20, 2015, 11:55 am by Vinniex1
Ok, couldn't see that on my iPad. Found another that suitable to Arduino outputs, and also supports 2 motors that are 5 amps each. This should support my needs?

Archibald

Ok, couldn't see that on my iPad. Found another that suitable to Arduino outputs, and also supports 2 motors that are 5 amps each. This should support my needs?
Where did you get the 5 amp requirement from?

Vinniex1


Archibald

My actuator/s are 5 amps.
My actuator/s are 5 amps.
Where did you get that 5 amps from? From measuring an actuator? From a data sheet that came with the actuator? Is that the current when under maximum mechanical load?

I am a little concerned that a 5 amp H-bridge would not give any margin, especially as the initial starting current would probably be higher than 5 amps.

A link to the new product you have just found could be helpful.

Vinniex1

It is described on the item page. The max load current would be 5 amps for one actuator?



H-bridge link:

http://robokitsworld.com/index.php?main_page=product_info&products_id=15

Actuator link:

http://www.ebay.com.au/itm/12-24V-Linear-actuator-1500N-Electric-Motors-Max-load-150kg-for-auto-lifting-/261355552308?pt=LH_DefaultDomain_15&var=&hash=item3cda013e34

Archibald

#20
May 20, 2015, 12:34 pm Last Edit: May 20, 2015, 12:39 pm by Archibald
It is described on the item page. The max load current would be 5 amps for one actuator?



H-bridge link:

http://robokitsworld.com/index.php?main_page=product_info&products_id=15

Actuator link:

http://www.ebay.com.au/itm/12-24V-Linear-actuator-1500N-Electric-Motors-Max-load-150kg-for-auto-lifting-/261355552308?pt=LH_DefaultDomain_15&var=&hash=item3cda013e34
Thanks, I had not seen the specification when I scrolled down the eBay web page; I think I had not allowed enough time for the web page to download. I see further down the page it says "Max load current=3A" so which do you believe?

As that is its maximum current, presumably under full mechanical load, I think the H-bridge looks suitable but I would still be slightly concerned by the initial starting current of the actuator's motor.

I doubt the actuator contains microswitches to cut off the power when it reaches each end of its travel. The motor's stall current could be well over 5A so I would fit external microswitches to limit the travel.

Vinniex1

#21
May 20, 2015, 12:50 pm Last Edit: May 20, 2015, 12:52 pm by Vinniex1
Ok. I could look for one with higher amps.

Just a question for the connecting to the Arduino.

Pin 1 on the h-bridge would make the actuator extend. Therefore, if pin 1 is connected to pin 14 on the Arduino, if I set pin 14 to high, it would make the actuator extend. Therefore, I would need 4 output pins on the Arduino. Right?

Also, would I just connect the GND input pin on the h-bridge to the GND pin on the Arduino?

The actuator does have limit switches on it. Therefore, it will not over travel.

JimboZA

The limit switches will only prevent over extension if you read them and act.
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Dr Perry Cox: "Help me to help you, help me to help you...."
Your answer may already be here: https://forum.arduino.cc/index.php?topic=384198.0

russellz

I have similar actuators on my gates.  Mine are rated 1200 N maximum force so are similar and they are rated at 3 A.  The actual current drawn will depend on the weight of the gates, the degree of friction, and the wind loading on the gates.  I'll see if I can measure it later.

They don't have limit switches.  The usual means of control is to have firm stops on the gates and to monitor the current drawn.  When it rises above a pre-set level for more than a second or two the travel limit is assumed to have been reached and the motors stop.  The next button push on the remote control reverses the motors.

If you have two gates you must have a delay between the two to prevent jamming.

Russell.
Retired after 40 years as a chartered engineer working mostly with RF and analogue electronics.

Archibald

#24
May 20, 2015, 01:10 pm Last Edit: May 20, 2015, 01:24 pm by Archibald
Pin 1 on the h-bridge would make the actuator extend. Therefore, if pin 1 is connected to pin 14 on the Arduino, if I set pin 14 to high, it would make the actuator extend. Therefore, I would need 4 output pins on the Arduino. Right?

Also, would I just connect the GND input pin on the h-bridge to the GND pin on the Arduino?
That circuit board has two H-bridges. For one actuator, using Pin 1 for forward and Pin 2 for reverse. You may need to be careful to ensure both pins are never 'high' together, especially when the Arduino is first switched on.

Yes, connect GND pins together.

You need to be concerned about back e.m.f. spikes from the motor.  We don't know if the power semiconductor components include protection diodes.

Vinniex1

Ok. It wouldn't hurt putting some diodes after the h-bridge this should prevent the back emf, if there is no protection in the module.

I really appreciate everyone's input and comments. Thank you.

Archibald

#26
May 20, 2015, 01:35 pm Last Edit: May 20, 2015, 01:36 pm by Archibald
I wonder whether it would be better using relays (wired up in a way to ensure it's not possible to short the 12V supply).

Perhaps I am being over-cautious is this thread.

russellz

Just checked the operating current on my gates.  The motors run at between 1.5 and 1.9 A normally.  The current varies according to the position of the gate as the geometry needs more force in some positions.

When the gate reaches the end stop the current rises to just over 5 A for about 2 seconds before the relay cuts out.

Hope that helps.

Russell.
Retired after 40 years as a chartered engineer working mostly with RF and analogue electronics.

raschemmel

#28
May 20, 2015, 04:33 pm Last Edit: May 20, 2015, 11:16 pm by raschemmel
It is customary to post all the data or information for your hardware in your first post. (as well as mention that you have it) , to save time.

As pointed out , the h-bridge you linked is inadequate.
You might consider this one.

Also pointed out, is the link for the actuator doesn't mention the operating current,
though 5A doesn't seem unreasonable for the 12" stroke .

Do you know how to draw a schematic ?
Please post a schematic or photo of a hand drawn schematic to facilitate discussion
about it.

You can roll your own H-bridge if you want but it's probably more trouble than it's worth.
SEE Reply #6 of this post.

 I did one using these:
P-channel mosfet

N-channel Mosfet

and one of these (TC4427)


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