Skidding winch

[John_Mc]

You don't have to increase the tractors RPM, the tractors governor kicks in and "maintains" the RPM you have set.

The added fuel from the governor, increases the torque that the engine puts out, to compensate for the added load.

SR

Yes, but...

The torque available from the tractor's engine decreases when operated below the peak torque RPM. So the governor will only keep up up to a certain point. If you are below your tractor's max torque RPM, increasing the RPMs will increase max available torque as well.

 

[CobyRupert]

So would you say that with a 6k electric winch as wraps increase the power cant be increased so therefore you loose pulling power? But on a 6k pto winch as the wraps increase to maintain pulling power at 6k, increasing the tractor's rpm will maintain 6k pulling power or until cable breaks?

Be careful of the terms. 6k is the pulling force. How fast (ft/s) you move the load (while pulling at that force) is Power.

Think of Power (as the product of) = Torque (Force) x Speed.

On a pto winch, it’s not that you would increase tractor’s rpm to maintain pulling Force. You’d increase tractor’s fuel to increase Power at the same rate that the cable Speed is increasing (on the reel) to maintain a constant 6k Force.

(I.e. Change in Power has to be proportional to change in Speed if Force is to be constant.)

 

[Oldpath05]

So.....letç—´ say tractor has a constant (fixed) rpm input to winch.
This makes a constant reel rpm, and would be a constant cable speed, but as the effective reel diameter increases the cable speed increases.
This means more power is required from tractor.

While more tractor power is required, itç—´ still at same PTO speed, this mean the torque that is passing through winchç—´ clutch is increasing. Clutch limits the Torque passed to drum.
Clutch also limits the power TO the drum, when tractorç—´ PTO is operating at a fixed speed.
Power OUT of the drum (cable) is also fixed. (Because power in =power out, ignoring losses ) Thus, if the cable pulling Power stays constant, the torque (pulling Force) decreases as the pulling speed increases (as effect reel size increases).
That makes sense and as expected.
And confirms that the pulling rating (in lbs) is dependent on if itç—´ first cable turn on reel or last.
And has little to do with the rpm your running winch at.

"letç—´ say tractor has a constant (fixed) rpm input to winch."<<<<No I cant say that because I always increase rpm on big logs to increase pulling power or my tractor will stall, that's why I think electric winches are different. My winch is rated for 3000 kg= 6613.868 lb, I round it off at 6k, so if clutch is not slipping because I got grease on clutch dics, to me that means at full throttle witch is ether 2500 or 3000, my winch should produce a 6k pulling force regardless of wraps til my 8 mm cable breaks or tractor stalls which it has before. So I'm still thinking I have 6k regardless of wraps.

Now if I had 10k pto winch my tractor motor wouldn't produces that much pulling power on a full wrap drum but maybe if drum had just a few wraps it would.

I think I got 6k pulling here at idle my tractor would stall. Big Hemlock log pt.3 - YouTube

 

[Jstpssng]

Sometimes I prefer to let it stall rather than have something else give up first. I'd much rather restart than break my winch or tractor.
Not so much when I had my 275 though, if I wasn't careful when the log snubbed up it would restart the tractor... running backwards.

Your L3400 handled that hemlock well. That was a heavy tree, probably half of the weight of your machine. :thumbsup:

 

[CobyRupert]

"let’s say tractor has a constant (fixed) rpm input to winch."<<<<No I cant say that because I always increase rpm on big logs to increase pulling power or my tractor will stall, that's why I think electric winches are different. My winch is rated for 3000 kg= 6613.868 lb, I round it off at 6k, so if clutch is not slipping because I got grease on clutch dics, to me that means at full throttle witch is ether 2500 or 3000, my winch should produce a 6k pulling force regardless of wraps til my 8 mm cable breaks or tractor stalls which it has before. So I'm still thinking I have 6k regardless of wraps.

Now if I had 10k pto winch my tractor motor wouldn't produces that much pulling power on a full wrap drum but maybe if drum had just a few wraps it would.

I think I got 6k pulling here at idle my tractor would stall.

I mean that once you set hand throttle and get off tractor to operate winch, the PTO speed is relatively fixed from that point on.

So yes, more “power” is being transmitted when you raise rpms in the sense that you’re pulling the load faster, but I think the maximum pulling force is the limit of the winch’s clutch, no matter what rpm it’s turning at.
This maximum force, that the clutch can transmit is converted into a cable pulling force (and cable speed) that varies depending on the diameter of the drum.

 

[Sawyer Rob]

So yes, more 闖殪wer is being transmitted when you raise rpms in the sense that you豎*e pulling the load faster, but I think the maximum pulling force is the limit of the winch逞ｴ clutch, no matter what rpm it逞ｴ turning at.

Your winch (each model/size of winch) has a HP rating "input", that it takes to get MAX out of your winch. Increasing your RPM beyond the minimum the winch needs for max power, will NOT increase the power of the winch.

To get MAX out of MY winch, it takes 20HP... Putting it on a 40HP will not make the winch pull more, once you put 20HP into my winch, that's all it can use to get max out of it. Like was said, putting more into it will probably just slip the clutch.

The confusion here is, at what RPM does YOUR tractor make the minimum HP your winch needs to make max pulling power?

My tractor being bigger with REALLY GOOD low end torque, doesn't need to spin very fast to make 20HP...

SR

 

[John_Mc]

Sometimes I prefer to let it stall rather than have something else give up first. I'd much rather restart than break my winch or tractor.

Not really an issue with a properly designed logging winch. The clutch slips before you put enough torque on the winch to damage it or your tractor.

 

[CobyRupert]

The confusion here is, at what RPM does YOUR tractor make the minimum HP your winch needs to make max pulling power?

SR

Yes, well said. But I'd substitute the word torque for HP in your statement.

When the tractor's torque output is less than the torque the winch's clutch slips at, then it's a different ball game, and stalls can occur.
This gets into the rpm/torque curve of the motor, which I was ignoring for the sake of simplicity. But you can't ignore this if the tractor's low end torque doesn't exceed the setting of the winch's slip clutch.

So yes, in this scenario, increasing rpms will increase the torque and pulling force up to the what's allowed by the slip clutch. -as John_Mc noted above. Increasing power and rpms beyond that only increases cable speed.

..and of course, having a fixed maximum amount of torque through the slip clutch means the "maximum" pulling force/torque at the cable will decrease as speed increases as the cable drum diameter grows.

I looked at Wallenstein info to see how they rate their winches (first cable turn on roll, middle, or last turn?). Didn't find an answer but found that the cable speed they list is a range that varies 2.33:1. Wow! I'm pretty sure that tells me that maximum cable pulling force (torque) will also vary by 2.33:1 from first turn on roll to last.

 

[John_Mc]

FWIW - my bet is that Logging winches are rated for the pulling force while the cable is on the first layer of winding. That's the most easily reproduced situation. Rating when the drum is full would also penalize a winch which shipped with a longer standard cable, since the advertised specs would look wimpier.

EDIT: Just heard back from Hud-Son, the US distributor of Uniforest logging winches. These winches are rated with half of the standard cable wound onto the drum. I find that interesting, since they usually ship with 230 feet of cable, standard. Most other brands ship with shorter cables.

 

[Oldpath05]

Does anyone use 230' of cable? I'd cut that in half, mine holds around 140' and that's more then enough. Sometimes when I'm winching at low rpm the tree will catch on something and stalls my tractor and some how the motor starts running backward, I have to shut it off and re-start, weird and sounds different to, that ever happen to anyone else?