One main reason for going PWM is it is more efficient and easier on any semi conductor components.
PWM controls the rpm by varying the Mean voltage level.
Any electric clutch would have to be power from full 12vdc separately.
Max.

 

I know some people that work with Ardrinos and I can keep my head above water with basic computer code so that might me an option. I have not used an Ardrino before.

From what I gather it could handle all of the logic that would otherwise be built with a series of Timer Relays. The relays are ~$40 a piece and I would need at least two. An Ardrino is ~$50.

In this case would the Ardrino completely replace the remote control provided? Seems like it would get input from the two high and low limit sensors and it own internal timer. Then based on that information would send a signal to the PWM that would move the motor at the desired speed. If any of the component can't be switched directly by the Ardrino then a relay need to be in the middle. In the right ballpark?

If the DC winch mentioned by Max or a similar one will be "reasonably" safe then I can get to collecting an H-bridge, Ardrino, wires and coffee. On further research the Ardrino looks like it can be programed to act like a PWM.

I figure it this way. While a winch isn't a hoist this is not going to be a permanent affair. Normally if this was going to be something permanent I would be screaming buy a hoist but a winch will do fine. Since this is a temporary thing you want to keep the project as economical as possible (economical as possible is a nice way of saying cheap). As to an Arduino or any micro controller I only suggest this method because what you have here is a pile of redundant repeatable task. Raise the curtain, wait awhile, lower the curtain, wait awhile, do it again. Micro controllers like doing task like that and yes, they can PWM a motor. Another merit to using a DC Motor winch is depending on current the thing can be driven with an off the shelf modular H-Bridge. The H-Bridge is easily driven by the uC making for simple. So my guess is short term project on a tight budget,

As to power for the motor? Consider a low end home computer power supply. There is your 12 volts.

Ron

 

Have you given up the one hour requirement? Warn winch might be in 26 RPM range or maybe 13 ft /min.

I will need to slow it down more than 13 ft / min. I do not need a precise or a continuous slow down. I just need to be able to adjust the total time it takes to raise and lower.

Normally if this was going to be something permanent I would be screaming buy a hoist but a winch will do fine.

My main concern, after finding out that 12v lifting hoists are relatively rare has been whether or not I can use the Warn winch with its load brake for the light vertical load in my project. Your comments and the fact that some of the Warn winches have mechanical brakes I can move forward.

According to Warn literature: "All WARN ATV winches have mechanical disc brakes, as opposed to the dynamic braking systems found on other ATV winches."

I know I will be using the winch for an unintended purpose but I think given the setup the risks are low. Besides "projects" are supposed do use things in goofy ways.

As to an Arduino or any micro controller I only suggest this method because what you have here is a pile of redundant repeatable task. Raise the curtain, wait awhile, lower the curtain, wait awhile, do it again. Micro controllers like doing task like that and yes, they can PWM a motor.

I am definitely going to go the Arduino route. I have wanted to learn for awhile and then I can use it on future projects. I am going to order the Mega today so I can start tinkering.

Another merit to using a DC Motor winch is depending on current the thing can be driven with an off the shelf modular H-Bridge.

The H-Bridge reverses the direction, right? Does that mean I would scrap the winches remote control handle and drive it with the Arduino PWM (via appropriate relay) and use the H-Bridge to switch directions?

PWM controls the rpm by varying the Mean voltage level.

After watching some tutorials on PWM that is what confuses me. For example on a 20% duty cycle PWM output the 5v Arduino would only output 1v dc. Does the PWM vary the mean voltage coming out of the 12v relay that is beefy enough to move the motor?

Any electric clutch would have to be power from full 12vdc separately.

By electric clutch do you mean the "self locking brake"? That seems easy enough to give 12v power to that separate than the motor drive. Thanks for the heads up.

Last thing before I go shopping. Any type of DC motor I should avoid because it will give me headaches when modifying it?

Right now I am going to get the $270.00 Warn RT15 (w/ Mechanical brake standard)
or
the $90.00 Warn Utility 2000 (w/ self-locking gear train (Rated Load Holding)) if I can confirm that the "dynamic brake" will hold when the power is cut.

 

The H-Bridge reverses the direction, right? Does that mean I would scrap the winches remote control handle and drive it with the Arduino PWM (via appropriate relay) and use the H-Bridge to switch directions?


After watching some tutorials on PWM that is what confuses me. For example on a 20% duty cycle PWM output the 5v Arduino would only output 1v dc. Does the PWM vary the mean voltage coming out of the 12v relay that is beefy enough to move the motor?

.

The power side of the PWM switches from between full power supply voltage to 0v, the resultant voltage pulses create a mean level of current required to drive the motor, the wider the PWM pulse the higher the mean level of current.
PWM can be unidirection control or bi directional depending on design features.
By clutch I also included brake in that.
Personally I would not go with SMPS or switching supply but a heavy duty linear supply.
Max.

 

Thank you to everyone for the help. I just ordered an Arduino along with all the other bits that seem to accumulate once you start on a project. Can't wait for it to get here.

Now I just need to buy a winch and then get to hacking.

 

The H-Bridge reverses the direction, right? Does that mean I would scrap the winches remote control handle and drive it with the Arduino PWM (via appropriate relay) and use the H-Bridge to switch directions?

No, I wouldn't be too quick to do that. I would leave things in place and work around the pendant remote control handle). If you look at these and similar winches they all have a nice sized DC motor with one large lead or terminal exiting them. That would be the main power lead. The unit you linked to mentions 10 Gauge battery leads. Generally speaking and winging it 10 Gauge wire supports a 40 Amp ampacity. The motor you are looking at also mentions 12 VDC, .4 Horsepower. 0.3 KW so under load and subject to vary the motor maximum current is 300 Watts / 12 Volts = 25 Amps. The minimum battery recommended is a 12 volt 12 Amp hour battery. Under a 25 Amp load a 12 volt 12 amp hour battery would last less than 30 min. So when considering a power supply you want a 12 volt supply capable of around 30 amps. So here is what I would do.

I would buy the winch making sure it will do what you want it to do, I believe the linked winch will. When you get the winch I would pile a 150 Lb load on the floor and set the winch to lift the load. Whatever, 150 pounds of junk on a pallet with straps. I would then lift the load and measure the needed current. Use a 12 volt automotive battery that's charged. Hell, if you are serious about all this I'll send you, absolutely free, a current shunt. All you need is a cheap DMM (Digital Multi Meter). This will tell you how much current you really need and how much current your H-Bridge needs to switch. That will remove a hellof a lot of guesswork choosing a H-Bridge and power supply.

This brings us to what Max mentions:

Personally I would not go with SMPS or switching supply but a heavy duty linear supply.

I would have suggested a linear supply but suggested a SMPS (home computer power supply) instead. My thinking here is simple. Linear supplies are great but greatness comes bundles with a cost factor. They are large when you start looking at 30 amp 12 VDC supplies, they are heavy, and they have very large price tags. If this project were to be a permanent project and had a big budget, I would run with MaxHeadRoom's thinking but in the interest of keeping cost down suggested the SMPS approach. Looking at the motors gear head ratio of 103:1 I don't see a large surge current on start. While not pretty I see a SMPS as a cheap solution. Running my above suggested test will really help determine what you need. Finally since the motor will run and rest I would not rule out using an automotive battery supported with a charger, just a matter of what is practical and cost productive.

Yes, as covered most off the shelf H-Bridges allow for PWM. Again, I would wait on buying any motor direction reversing anything till we know the motor current.

Ron

 

No, I wouldn't be too quick to do that. I would leave things in place and work around the pendant remote control handle).

Thanks for the clarification and thanks for the Amps calculation.

I would buy the winch making sure it will do what you want it to do, I believe the linked winch will.

Ok, I will do that. It will take a couple days to get here. You did your calculations on the $270 one with the mechanical brake. That answers my question on whether I can get the $90 one with just the dynamic break. Guess not.

This will tell you how much current you really need and how much current your H-Bridge needs to switch. That will remove a hell of a lot of guesswork choosing a H-Bridge and power supply.

When I get the winch I will do the test you describe so I can get the right power supply.

While not pretty I see a SMPS as a cheap solution. Running my above suggested test will really help determine what you need. Finally since the motor will run and rest I would not rule out using an automotive battery supported with a charger ...

Good idea about the battery hooked up to a charger but that will not work in this application.
I found a 30 amp 12v switching supply for ~$25 on Amazon. So at least that will work out.

 

My saying that a winch is not a hoist is before knowing what you are doing. A winch is fine for this.

 

I appreciate the original safe advice. Do you think a dynamic brake winch would be enough or is it best to get a winch with a mechanical brake? Not sure if the mechanical brake winch has the dynamic brake as a backup or not. Online reviews say that much heavier loads than I will be using are held fine by the dynamic brake winch.

 

For your light loading my guess would be dynamic braking would be fine, however, actual winches are not my forte so hopefully someone with a good working knowledge of these things will be back. Tcmtech does a lot with stuff like this and hopefully he will be back.

Ron

 

Also your winch speed can be cut in half by the use of a "snatch block". Or even slower by multiple snatch blocks. I have an older version of the lowest price harbor freight winch for pulling logs out of the woods but have never used it for a hoist.

My son has one of these but I've never used it, he uses it to pull motors and is pleased with it. http://www.harborfreight.com/catalogsearch/result?q=electric+hoist

 

Thanks. I know I can use a snatch block but for this application I need almost the full length of wire. Also multiple snatch blocks might get tangled in this use case. Waiting on the Arduino to arrive and then on to the winch testing and tinkering.

 

My Arduino arrived yesterday. So far have done the customary Hello, World - Blink. I then modified the circuit to operate the led with a push button. Still very basic but I think I will be able to figure it out.

I settled on this DC winch from Superwinch. It is relatively cheap ($116.00) and importantly has a mechanical and dynamic brake.

Now just waiting for the winch to arrive to do Amp tests. According to the manufacturer the winch draws 15 Amps under no load and up to 180 Amps under full load. 1.2 HP permanent magnet DC motor , 3-Stage planetary gears, and 136:1 gear ratio.

Also, found this 50 Amp motor driver for $120.00. If the Amp test is low enough I think I could use this to drive the motor slowly from the Arduino.

Till then more fun with the Arduino.

 

Cool and nice to see things moving along. Little by little with the Arduino things will come together. Eventually you sit down with a sheet of paper and write what you want to do step by step with the micro controller and transpose it into code. Once the winch current is known then worry about an H Bridge to drive it.

Ron

 

the winch draws 15 Amps under no load and up to 180 Amps under full load

So you'll need a beefier supply than originally thought.

 

Loading a 3000 lb winch with 100 lb = about 4 % of capacity, winch will think it is unloaded. A 30 A or 50 A supply should be plenty. Might need a soft start as there will be a slug of current drawn at start.

 

At 27 feet per min unloaded (which is basically what your load will be) on the first cable wrap of the drum, don't think PWM will slow it down enough. The first post said, "30 feet in 45 minutes".

 

Slowing motor down to about 1 RPS might be difficult, but could burp it, slow it down to 500 RPM ??, then lift 6 inches then wate for 45 seconds & repeat.

 

I have a couple of these type winches. One motor burned out, so I took it apart, and am making it into one powered by a chainsaw engine. The one I'm converting is a Superwinch brand, the drum is ~2 1/2" diameter. So that makes it ~8" in circumference. At that diameter it would be one RPM on the drum for 30' in 45 minutes. Most of these winches have planetary gearing in them, around 150:1 to 180:1 ratio depending on the model of winch. The sun gear is part of the motor shaft. Also each layer of cable makes them retrieve at a faster FPM.

These small winches also have a very low duty cycle, 15 seconds run then 15 minutes rest to cool down.

 

Lukehoist--sounds like you need to do almost exactly what I need to do: winch something very slowly. I joined this forum to ask help in making a simple 555 astable timing circuit to "pulse" an electromagnetic clutch (approx. 5 seconds on / 10 minutes off) in order to pull a load slowly across the ground. Gear reduction in the range I needed was going to be very expensive and I didn't need continuous movement. Sounds like you've settled with the Arduino path; probably better since you have direction reversal and multiple cycles to deal with. But I thought I'd throw out the 555 timer circuit option since it's only a few dollars worth of components and "cheap" was a design consideration.