"Powersafe" clutch on BCS

[NibbanaFarm]

What you're describing is exactly the clutch packs in an automotive automatic transmission. A multi plate wet clutch that is engaged hydraulically. And they are excellent although I'm sure it's possible to make a bad one. Generally very strong and long wearing from what I've been told.

The reason you put a car in neutral at a stop and release the clutch pedal is to save wear and tear on the throw out bearing. In this case there wouldn't be a throw out bearing so it shouldn't have any effect. I'd say it should run happily that way until the epoch without any more wear than putting it in neutral. (But I've been wrong before.)

I only have about 20 hours on my 739 and it's going to be a long, long time before she sees 2000 hours. It might be my imagination but it seemed like the power safe clutch was pretty "grabby" at first. Now it feels like it engages a little more smoothly. Might be my imagination or maybe I'm just getting used to it. Anyway, what takes me an hour of hard physical labor, this thing does in 10 seconds. I like it so far. No complaints.

 

[Jens767]

Hi Joel

Thank you for your update on the PowerSafe clutch, for sharing your experience and concerns with us and for clarifying how this new clutch works. Have you been able to find out, if there is a "braking mechanism" within the new clutch?

Now I better understand that my concern about leaving the tractor in gear with the engine running, was unfounded. As I am more familiar to a normal old-fashioned mechanical clutch, I was worried about putting unnecessary stress on the throwout bearing, but sadly, I was not able to find the proper English term for it. Thank you NibbanaFarm :thumbsup:

As you also recommend, I always disengage the PTO when I empty the bag on my lawnmower, and I also flip the reverse-lever to the reverse position. Should the clutch somehow engage, the mower does not operate, and the tractor moves away from me.

I guess we all cross our fingers that the PowerSafe clutch will prove strong and durable, as it is probably a complicated and expensive mechanism to repair, should it fail. After a modest 87 hours of experience, I am very satisfied with the hydraulic clutch. I use my BCS 740 with a high-torque lawnmower, and a low-torque sweeper.

Using a low-torque implement - or none at all, you can almost just "drop" the clutch lever, as I would also do with a mechanical clutch. Using a high-torque implement however, I cannot quite recognize your description. As the clutch was brand-new, I could easily stall the engine if I just let go of the clutch by accident. Like NibbanaFarm, I also have the impression that the clutch has become smoother over time. I have the impression that it might be due to the clutch discs needing a breaking-in period to work properly, but perhaps it is just me becoming more familiar and confident with the tractor.

It will probably take a long time until one of us reaches 2000 - or even 1000 - hours on our tractor, so I am pleased to read that Earth Tools has put a BCS 749 on the "test-bed". Thank you to everyone who contributes with their experience and knowledge.


Best regards

Jens

 

[NibbanaFarm]

Sorry to take so long to get back to this thread Jens. If my understanding is correct, on a Powersafe, with the clutch pulled in, or the safety lever released, it should be just like an automotive automatic transmission in park or neutral. Bearings turning but under no load and in an oil bath. Not much reason for wear.

What I don't understand is why the type of clutch would make a difference in the "braking" effect of disengaging the clutch. Any explanation for this? I don't have anything but light load equipment. The machine does stop very quickly. It might be my imagination, but it seems like it does stop less abruptly if I slowly disengage the clutch.

 

[oldmech]

Hi! Powersafe is a hydraulic control clutch. They are one pump oil filter and a multi-position valve with a two-way hydraulic piston on a multi-disk clutch.
So when you stop the piston move and remove pressure on clutch disks on BRAKE the clutch disk. They are a brake inside clutch. (The safety law ask to stop all move in less one second) I think if you release or press slowly the lever you can reduce the hard brake action.

I take a look on AGRIA safety clutch. They use a Electro-Magnetic clutch system. The electro-magnetic clutch are a lot more fast than hydraulic

So fast Agria put a electronic device for to get the system more smooth. The problem or trouble with electro-magnetic clutch is heat.

But Agria Electo-Magnetic coil run in oil with the multi-disk clutch system so less heat more reliable.

Now in car They are Electro power steering. Electro safety break. etc.. Good luck! Oldmech

 

[dogwoodhillfarm]

My husband and I are new farm owners and have decided to purchase a BCS tractor (with plow, tiller, flail mower and chipper/shredder) We're trying to decide between the 749 and 853. I think we've decided on a gasoline engine, but are now weighing the pros and cons of the powerclutch. We will both be using the tractor. I don't like to drive a stick automobile, so I am attracted to "ease of use" aspect of the Powerclutch, but also like the "ease of repair" features of the standard clutch. The reality is that even with the standard clutch, we would probably rely on our local dealer for repairs. Now that the Powersafe models have been out for a few years, I was wondering if any of ya'll have any updated experience or opinions?

 

[Maxxjod]

Hi, i have read this thread with some interest as i am the Technical Director for the UK distributor of BCS 2 wheel tractors.
We have been selling PowerSafe equipped machines since 2011 and in that time we have sold over a 1000 machines, so far we have only had a very small amount,20-30, of issues with PowerSafe clutches the most common issue causing problems is people using the incorrect oil gearbox oil which leads to the clutch 'dragging'. The actual issue is that the oil being too thick causes the clutch plates to drag in the oil, a small amount of resistance on the handle bars stops the machine from driving. As a matter of course we always advise customers to place the machine in neutral and disengage the PTO when leaving the machine that way if the oil is causing clutch drag it will not be an issue to the operator.
I have had to dismantle some clutches to resolve the incorrect oil issue and i have to say that they really aren't that difficult to dismantle, you just need to have a nice clean work bench and some way of cleaning the components.
I have seen very little and indeed almost no wear to any of the clutch components in machines that have been used for 2-3 years, the only time i have seen any wear was on a machine that had been used to sweep artificial grass and had had the gearbox dipstick left out while in use, this allowed fine sand to enter the gearbox and cause a number of issues to the PowerSafe clutch unit.
From what i have seen and experienced while using PowerSafe equipped machines i would have absolutely no hesitation in recommending a PowerSafe equipped machine, if nothing else the clutch lever is very light in operation.
I think the best piece of advise that i could give any PowerSafe equipped machine owner is to change the gearbox oil on a regular basis, once every 6 - 12 months.
I would be interested to hear of anybody's experiences with PowerSafe equipped machines.

 

[Jens767]

Hi Maxxjod

Thank you for your reply - and welcome to this great forum!

Most members in here are end-users like me, and very few of us will ever reach large 4-digit hours on their 2-wheel tractors. Therefore, I highly appreciate, that a handful of importers, distributors and dealers like you, are willing to share your experience with all of us :thumbsup:

I am approaching the first 100 hours on my BCS 740, and thereby my first oil change in the gearbox, and I will of course like to avoid changing to the wrong oil, as you mention.

My user manual recommend AGIP ROTRA MP SAE 80W/90. AGIP products are very common in Italy of course, but here they are hard to find. If I understand your reply correctly, the most important issue is the correct viscosity - in this case, 80W/90. Here in my area, I have seen for instance Castrol EPX 85W-90 and EP 80W-90, so I would like to hear your comments on those, or hear if there are other products out there, that you would rather recommend.

Thank you very much.


Best regards

Jens

 

[Maxxjod]

Hi Jens,

We have found that the most important part of the oil spec is the API GL5 part of it, BCS originally specified a API GL4 gearbox oil. We use a Rock Oil product by the name of U.T.T.O is a tractor transmission oil that is SAE 80W API GL4, the closest oil to this that most of our customers have been able to obtain is Kubota UTD fluid. When BCS changed the spec of the oil from API GL4 to API GL5 we found that sometimes machines when cold, under 10c, were slightly sluggish until the gearbox oil warmed up. Any machine that comes through our workshop is filled with the Rock Oil product previously mentioned.

Please find a list of the oils we now suggest below-

Fuchs Titan Hyp 90
Valvoline 80w-90 GL-5
Morris EP80w/90 API GL5
Castrol EPX 80w-90
Motorex Hypoid SAE 80w/90 API GL5
Millers Hypoid 80w90 GL5
Comma EP80w-90 GL5
Agip Rotra MP 80w-90
Rock Oil SD API GL5 80w/90

I hope this helps you find a suitable oil for your machine, if in any doubt just send a link for the oil you are thinking of using.

Best regards

 

[Jens767]

Hi again Maxxjod

Please excuse me that I haven't replied to your last post long time ago :ashamed:

Thank you for your recommendations regarding the correct oil for the gearbox - obviously a very important issue for any hydraulic clutch.

I changed the oil in the gearbox in July last summer, and I used Castrol EPX 80W-90, which seems to work fine.

Hi again NibbanaFarm! You, Joel, me - and probably many other users as well, were rightly surprised over the hard braking of our tractors at first. Up until now, I haven't seen any "hard evidence" of a braking mechanism in the PowerSafe clutch - but I've also been wrong before Could it simply be due to the resistance from a very high gear reduction ratio through the gearbox, combined with all the internal friction in the gearbox from bearings, gear wheels and the clutch rotating in an oil bath?


Best regards

Jens

 

[NibbanaFarm]

Greetings Jens,
Five posts above yours, OldMech says that the PowerSafe clutch has a brake in it. So pulling in the clutch lever not only releases hydraulic pressure on the clutch disks, but applies a hydraulic brake in the clutch mechanism. At least that's what it sounds like to me. Now this has me intrigued and I'm almost looking forward to having to take mine apart so I can get a look at this thing. Note I say "almost". I do believe that this is true just by the way the thing feels.

I can say that mine has gotten considerably less "grabby". There is a sweet spot of about 1/4 inch (6.35mm) movement at the lever end between clutch release and brake application. If I'm very careful, I can get it to coast without braking when I pull in the clutch. The only annoying thing about it is when I'm riding a sulky or trailer moving relatively fast and the brake abruptly applies.

To me it really doesn't make all that much sense to have the brake in there. All the soil working implements have very little inertia and I think would stop pretty quick without a brake. Same with the snowblower; the spinning parts are pretty darn light.

I don't know about all the mowers but my bush hog has an overrunning clutch so it keeps spinning even with the clutch pulled in. I'm guessing any mower would have to have this feature. If not and the tractor didn't have a brake, the mower would continue to drive the tractor. In the case where the tractor has a brake, the mower would probably self destruct by stopping instantly. I'm not sure about this but that's my guess.

Either way, these things are really excellent. Mine has done so much work for me I can't even count that high. I love these things. They are infinitely useful. I am probably around the point where I should change that gear oil too. But the fluid that's in there is so clean that I can hardly see it on the dipstick. I have changed the filter once. The gear oil in there is absolutely perfectly clear as water.

Maxxjod, why is it necessary to change the gear oil so frequently in these things? What exactly is wrong with the fluid that's in there?

Thanks.

 

[Jens767]

Hi again again NibbanaFarm

OldMec could easily be right - especially with all the safety-stuff our politicians comes up with these days. Joel also thinks there is a brake function in the PowerSafe clutch. It could be interesting to hear firsthand from someone who have dismantled a clutch, if they found a brake function inside.

When the mowing-season begins, I will try to see if I can also find the sweet spot you mention - sounds interesting.

I can imagine this brake function being annoying when you use the tractor with a sulky or trailer. For an unprepared user it can even be dangerous, and that's probably why BCS has put a leaflet in the user's manual, encouraging users not to use sulkies or trailers.

Officially, you only have 3 gears in either direction on the BCSs with the PowerSafe clutch, as the transport gear has been blocked in the gear quadrant. Have you been able to find the 4th gear on your tractor? That might come in handy, if you use sulkies and trailers a lot.


Best regards

Jens

 

[Maxxjod]

Hi,

The PowerSafe clutch came about due to a change in EU regulations in 2009, some of the key parts of these new regulations are,
1) The engine must not be used as part of the operator presence control(deadmans) system.
2) The machine must have a 2 stage reset after the deadmans lever is released.
3) The machine must stop within 2 seconds of the deadmans lever being released.
4) The machines maximum travel speed was reduced.
5) Machines must not exert a force over a certain amount in neutral on a slope.
So as a result of these changes BCS decided to design a new style of clutch to resolve many of the regulations.

The PowerSafe clutch uses oil pressure to push a piston forwards that then pushes the drive plates together to provide drive, the clutch unit has a small oil pump that produces around 7-8 bar. When the deadmans lever or clutch lever is released the oil is able to bypasses the clutch piston which then releases pressure on the clutch plates, this release of pressure separates the clutch plates and locks them in place inside the clutch housing causing the machine to stop within 2 seconds. There is no separate braking system in side the clutch or gearbox its all done through the PowerSafe clutch unit.

Due to the revised regulations there is no 4th gear due to the speed it produced, the gears for 4th are not in the gearbox so unfortunately its not just a case of modifying the gear selector plate.

It is not a good idea to use the 'sweet spot' to allow the machine to coast as it could cause rapid wear of the metal on metal clutch plates in the PowerSafe clutch unit, the plates are intended to be either engaged or disengaged not dragging in-between.

It is very important that oil changes are carried out on a regular basis to ensure that the clutch unit is free of any contaminates and has the best quality of oil, while the oil may look clean its EP qualities may have degraded, we recommend that gearbox oil and filters are replaced every 6 months.

I have recently been to BCS for my annual factory training and the PowerSafe clutch units being produced now are exactly the same as the ones first produced in 2011, BCS have found no reason to change any of the PowerSafe clutch components due to wear or damage, i think this shows how good the PowerSafe clutch system is.

Regards

Maxxjod

 

[David Cockey]

Can a Powersafe unit be moved without the engine running, or are the wheels and tires prevented from rotating?

 

[NibbanaFarm]

Wow, that was a lot of excellent information. Thanks Maxxjod.

David, the tractors can be moved in neutral, with or without the engine running. With some difficulty. They can't be moved in gear though. At least I can't move mine while in gear.

 

[rickyd79]

Hi,

The PowerSafe clutch came about due to a change in EU regulations in 2009, some of the key parts of these new regulations are,
1) The engine must not be used as part of the operator presence control(deadmans) system.
2) The machine must have a 2 stage reset after the deadmans lever is released.
3) The machine must stop within 2 seconds of the deadmans lever being released.
4) The machines maximum travel speed was reduced.
5) Machines must not exert a force over a certain amount in neutral on a slope.
So as a result of these changes BCS decided to design a new style of clutch to resolve many of the regulations.

The PowerSafe clutch uses oil pressure to push a piston forwards that then pushes the drive plates together to provide drive, the clutch unit has a small oil pump that produces around 7-8 bar. When the deadmans lever or clutch lever is released the oil is able to bypasses the clutch piston which then releases pressure on the clutch plates, this release of pressure separates the clutch plates and locks them in place inside the clutch housing causing the machine to stop within 2 seconds. There is no separate braking system in side the clutch or gearbox its all done through the PowerSafe clutch unit.

Due to the revised regulations there is no 4th gear due to the speed it produced, the gears for 4th are not in the gearbox so unfortunately its not just a case of modifying the gear selector plate.

It is not a good idea to use the 'sweet spot' to allow the machine to coast as it could cause rapid wear of the metal on metal clutch plates in the PowerSafe clutch unit, the plates are intended to be either engaged or disengaged not dragging in-between.

It is very important that oil changes are carried out on a regular basis to ensure that the clutch unit is free of any contaminates and has the best quality of oil, while the oil may look clean its EP qualities may have degraded, we recommend that gearbox oil and filters are replaced every 6 months.

I have recently been to BCS for my annual factory training and the PowerSafe clutch units being produced now are exactly the same as the ones first produced in 2011, BCS have found no reason to change any of the PowerSafe clutch components due to wear or damage, i think this shows how good the PowerSafe clutch system is.

Regards

Maxxjod

Hi Maxxjob

One question: In regards to "slipping the clutch" or the "sweet spot" as you put it, sometimes I find it necessary to "slip the clutch" in order to get into first gear and or to engage the PTO. Are you of the opinion that the 2-3 seconds this takes may damage the clutch? If so, what do you do to get it into gear when "gears" are not lined up? Of course one could roll the tractor, but who wants to do that...

thanks!

 

[Maxxjod]

Hi Rickyd79,

Using the clutch to 'feel' the gears in is fine, its using the 'sweet spot' to allow the machine to free-wheel with a trailer/sulky on that would cause the issue to the PowerSafe clutch.

Maxxjod

 

[Jens767]

Hi Maxxjod

Thank you very much for your post - but most of all for sharing your knowledge regarding the PowerSafe clutch with all of us :thumbsup:

If I understand you right, the PowerSafe clutch has an extra feature compared to a more conventional clutch, which is to lock the clutch plates inside the clutch housing when disengaged, causing rotation to stop within 2 seconds. This confirms what a number of members who have had the chance to drive a BCS with the PowerSafe clutch have experienced, and this explains why the 4th transport gear has been blocked/removed, and that the use of sulkies and trailers are no longer permitted. As mentioned on page 10 in this thread, there seems to be a difference in the way the 3 working gears works, compared to the transport gear though.


Best regards

Jens

 

[Maxxjod]

Hi,

The easiest way to explain the PowerSafe clutch to our customers is that it works in reverse to the standard BCS clutch. The original clutches, pre 2011 for UK, used rather large scary springs to provide the drive to the gearbox from the engine. The spring or springs in the clutch pushed the central part of the clutch against the outer part to provide drive, pulling on the clutch lever pushed the inner part of the clutch towards the engine to release the clutch, in the same way an automotive clutch works. Now the issue with this system is that if any external part of the clutch system such as the lever, cable etc is missing or badly damaged the machine will continue to run. On the PowerSafe clutch the springs are replaced with oil pressure and the whole clutch operation is flipped around, this means that if any damage to the cables etc occurs the clutch will not operate leading to a safe condition of the machine.

You may have seen this video before but it does show how the clutch system works-
BCS hydraulic clutch PowerSafe® - YouTube

 

[oldmech]

Hi! In PowerSafe Clutch. They are a brake. I explain! When engine is not running. Clutch is innoperative! You cannot free the transmission input shaft, This one is blocked or braked by four circular springs Parts 56556213 on disks (4) of transmission input shaft ( If you remove these springs no more brake)

When you start engine, Pressure pump go up and you can by a valve add pressure on a circular piston, This one compress the springs(4) free the disks(4) from gear box and add pressure on shaft disks from engine for turns transmisssion input shaft.
The Piston in clutch is one way. The brake action are from springs (automatic)
I think PowerSafe is a good system for safety, But the hydraulic pump takes some power from engine . I dont know How Much?
Good luck Oldmech

 

[Luisella]

NibbanaFarm hi,

I have done two oil changes, once a year at the end of the season. The fluid was clear in my tractor as well, however the magnetic plug was fairly well coated with metallic particles on both ocaisions, perhaps a little less on the second oil change.

Maxxjod hi,

Thanks for that from me as well. Really every six months! did they suggest perhaps six months or x number of hours?

Best regards

Lu