Continuous/Peak 40A/60A Control

Other Hardware Motors, Mechanics, Power and CNC
1

Hello

I am looking to control a 750W 12V DC wench. The wench is used to raise a mast but the speed at which it raises and lowers is too quick. With max weight on the mast the wench draws a continuous 30A. I would to have a good 10A of buffer just in case I want to make the mast longer or add more weight.

I have attempted with a Pololu vnh5019 remapped in single channel (24A Cont/60A Peak) and it worked well but its not suitable for this project due to the load being drawn. What I am looking for is a solid continuous 40A shield for the Arduino. I have done some looking around but nothing pops up that can be mounted on the Arduino. I am trying to avoid a driver board because I'm running low on space and have some other things I would like to add, separate from controlling the motor.

I understand that pulleys are an option but I also would like to avoid a pulley system. Any recommendations would be greatly appreciate.

Thanks guys! :slight_smile:

2

Have you seen this ?

3

I would be reluctant to want to package a 750 watt PWM driver into a shield form factor. Just proper connector sizes for that level current mounted on a shield would be a trick.

4

I think you are missing something. You are NEVER going to find a 750W driver in a shield form factor because the heat physical size is larger and the heat would transfer to the arduino. If you want 750W, forget about the idea of finding it in a plug in shield. I don't think that is ever going to happen.

Check out these:

5

raschemmel:
Have you seen this ?
50A Dual channel H bridge Motor Driver Module for Arduino Robot Chassis Servo for sale | eBay

I think I will try this. Its not quite what I was looking for but it seems like it would do the trick. I can make room for it. Currently I have been using DPWM simply because I'm not too familiar with programming the analog yet. I have just been setting a output on and delay in xxx microseconds and output off with a xxxx delay in microseconds. As far as reversing I have been using a couple SPST relays. Is there any reason why I would use analog instead of digital?

Thanks again

6

Currently I have been using DPWM simply because I'm not too familiar with programming the analog yet. I

Take a look at the two example sketches. Picture a robot with two motors one on the left and one on the right. To go forward
One of the H-BRIDGE mosfets must be on and another one must be off for both motors. Look at the comments and you should be able to see how the speed is controlled with ENables and the direction with INputs.
I have more examples when your ready.

L298_MOTOR_DRIVER_10.ino (2.38 KB)

L298_MOTOR_DRIVER_9.ino (1.85 KB)

7

Below are some h-bridge type motor controllers that might be of possible use. You probably actually can just add a MOSFET to your current relay setup to control the motor speed. Put the MOSFET on the ground side of the power supply and use it to PWM the motor speed. The relays will still control direction. A single DPDT relay might also be used in this type of MOSFET setup.

http://www.ebay.com/itm/New-DC-15-24V-40A-Brush-Motor-Driver-Module-Drive-Board-80A-MAX-/251264559326?pt=LH_DefaultDomain_0&hash=item3a8088e8de#shId

http://www.ebay.com/itm/Double-BTS7960B-H-bridge-68A-Motor-Driver-Module-For-Smart-Car-Arduino-/170917911112?pt=LH_DefaultDomain_0&hash=item27cb805a48

http://www.ebay.com/itm/0-36V-Rated-15A-Peak-60A-Dual-Channel-Motor-Driver-H-Bridge-Strong-Brakes-0-99-/120934988327?pt=LH_DefaultDomain_0&hash=item1c28497a27

8

Note the presence or absence of heatsinks on these. The one with no heatsinks on the mosfets is probably designed to have a solid heatsink running horizontally with mica insultors or individual heatsinks. They are probably absent to allow you to choose how you want to do it. I don't believe the intent is to use it without heatsinks. They probably assume you know if you need them or not.
Here's a link for the heatsinks you need

https://www.google.com/search?q=l298+heatsink&rlz=1C1GPCK_enUS504US504&es_sm=93&tbm=isch&imgil=QejbWzXKV6351M%253A%253Bhttps%253A%252F%252Fencrypted-tbn3.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcRpiEaa43xoQRYGgTBs-QqS3TXsFYSbMBrx1SRz13zhBV7-4x2X3w%253B373%253B500%253B2gCA5v26yAJuXM%253Bhttp%25253A%25252F%25252Fletsmakerobots.com%25252Fcontent%25252Fl298n-dual-full-bridge-driver&source=iu&usg=__PFMAyocrECIb7czzqJjkl3Cg02A%3D&sa=X&ei=FKlnU6i2Co_eoASAvYCgBg&ved=0CEAQ9QEwAg#facrc=_&imgdii=QejbWzXKV6351M%3A%3ByQpD8B2Ys8AloM%3BQejbWzXKV6351M%3A&imgrc=QejbWzXKV6351M%253A%3B2gCA5v26yAJuXM%3Bhttp%253A%252F%252Fletsmakerobots.com%252Ffiles%252Fuserpics%252Fu1533%252FL298N_heatsink.jpg%3Bhttp%253A%252F%252Fletsmakerobots.com%252Fcontent%252Fl298n-dual-full-bridge-driver%3B373%3B500

9

Those are great sketches for reference. I certainly appreciate it. I think after weighing my options I am going to implement a pulley system and try to stick with the Pololu VNH5019 remapped to single channel. This should cut my load down within tolerance.

Thanks again for all the help

10

Those are great sketches for reference.

I have about ten more if you want to look at them (one at a time).

11

For cheap you could put a couple of power rectifier diodes in series in the supply to the motor and drop the voltage to the motor to slow it down.

12

raschemmel:
I don't believe the intent is to use it without heatsinks.

So I can just purchase an after market heat sink and apply it on http://www.pololu.com/product/2507 for more tolerable performance? I was researching ways to get it on the board. Is thermal adhesive strong enough to keep the sink on while being suspended upside down?

13

No. That's why the Mosfets have the mounting screw hole in the heatsink tab.

14

In a case of a surface mounted mosfet is it possible to put a heat sink on top of it with thermal adhesive?

15

macarpenter:
In a case of a surface mounted mosfet is it possible to put a heat sink on top of it with thermal adhesive?

Yes but it won't do very much as its not thermally bonded to the metal of the drain
which is where the heat comes from.

For best heat conduction with surface mount you need the sort of MOSFET package
with a large drain pad on the bottom and you must use an IMS PCB (aluminium cored
single-sided PCB).