PWM on 12volt winch?

[Maglatron]

so I was thinking could I use PWM with a power relay that handled the amperage possible?

 

[Maglatron]

Personally I'd use a 100A device (with suitable thermal/overcurrent trip, resettable) and be careful how I used it. I'd also use a bypass switch to run it at full current when that was necessary - probably not very often.


Even a low current controller can be modified to work at MUCH higher currents by changing the switching device (probably a MOSFET) for one - probably a few wired in parallel - device rated for much higher current.

You can get N-channel MOSFETs rated at 30V and 500A (IRDS(on) value of 0.0007ohms!) for £1.20 at Farnell.

Use any good component supplier and their parametric search engines.

so could you elaborate on how to do this please?

 

[Minder]

You don't have the motor technology yet. do you?

 

[Maglatron]

You don't have the motor technology yet. do you?

Not yet, working on it. If I were to pay for someone's services I would pay for another winch and let whoever wants to take the job determine the motor type and figure out how to control it's speed and make a nice little control box and send me the winch with the modification of the added control box / panel. Easy money for those that know how! I have to mention, this speed controlled winch is a neccessity for me!

 

[Maglatron]

But yes still at the moment trying to get hold of my mate but I'm betting even if I do I wouldn't trust that he'd be able to help to be honest with you! like I say he's not too technical!

 

[Maglatron]

or perhaps you could point me to a winch that you already know the motor type, for me to buy, and the talk me through modifying a low current controller to handle the high current that the winch needs, maybe?

 

[Alec_t]

I want to gradually increase the speed of the winch, not just on or off, to take out the jerk,

Couldn't you simply pull the load via a strong coil spring to avoid the initial jerk?
Are you sure the winch doesn't already have a soft-start feature?

 

[Maglatron]

no not sure, I did think of the spring idea but for my needs, it isn't pheasible I am using the linear motion to convert to rotationals motion, I want to put a sprocket on to the shaft and turn a half ton flywheel via chain!! the inertia is obviously resistance to acceleration and I fear that the winch would snap the chain need gradual power onset and acceleration!

 

[Maglatron]

I might just use a centrifugal clutch infact

 

[Alec_t]

I fear that the winch would snap the chain

More likely the winch motor would stall or cut out, if the chain has been properly specified. With half a ton of flywheel attached the inertial load could keep the motor nearly stalled for quite a while.

I might just use a centrifugal clutch in fact

Per the posted spec, the winch already has a manual clutch.

 

[Maglatron]

More likely the winch motor would stall or cut out, if the chain has been properly specified. With half a ton of flywheel attached the inertial load could keep the motor nearly stalled for quite a while.

Per the posted spec, the winch already has a manual clutch.

Yes, but the centrifugal clutch wont stop the motor from turning and will give the flywheel chance to catch up to speed so that it runs in unison with the winch burning clutch is better than burning winch!!!

 

[Maglatron]

Alec_t said:


More likely the winch motor would stall or cut out, if the chain has been properly specified. With half a ton of flywheel attached the inertial load could keep the motor nearly stalled for quite a while.

this is the reason I need to gently introduce the power

 

[Maglatron]

Per the posted spec, the winch already has a manual clutch.

that clutch is either engaged or not, there's no slip

 

[Alec_t]

I want to put a sprocket on to the shaft and turn a half ton flywheel via chain!

Why not simply use a geared AC motor with VFD control, rather than the winch?

 

[Maglatron]

that's definatly a possibility never seen one before, what is the highest gear ratio you have come across because I still need the high torque, thanks

 

[Maglatron]

ok that is probably the most usefull thing that I have heard about yet, thanks man

 

[Minder]

If looking at mains options for the 2HP winch you have spec'd in, there is also the readily available TreadMill motors that go up to 2Hp - 3 HP.
The example of one of the popular MC2100 controller that uses PWM and slow ramp up, desirable in a TM.
The one thing to add for this option is a reversing relay.

 

[Maglatron]

could you suggest a way of fixing a sprocket to this one

(14) Worm Gear Motor 120W Ac 220V Speed Control Governor Industrial | eBay

Governor Power: 120W. Rated Power: 120W. Item Type: Worm gear motor. Feature: 1. 1 x Governor. Rated Frequency: 50/60 HZ. Motor Speed: 1400/1700 r/min. If you do not receive our reply within 48 hours, pls.

www.ebay.co.uk

 

[Minder]

That is a fraction of the motor power to the original one mentioned?!

 

[Maglatron]

hmm ok I'm open to suggestion I take on board what you said about the tread mill motor will look into that, just looking for a heavy duty speed controllable motor let me know!